Patent Publication Number: US-10333591-B2

Title: Bitrate efficient transport through distributed antenna systems

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 15/626,689 (hereafter the &#39;689 application) entitled “BITRATE EFFICIENT TRANSPORT THROUGH DISTRIBUTED ANTENNA SYSTEMS”, filed on Jun. 19, 2017 which is a continuation application of U.S. patent application Ser. No. 14/737,230 (hereafter the &#39;230 application) entitled “BITRATE EFFICIENT TRANSPORT THROUGH DISTRIBUTED ANTENNA SYSTEMS”, filed on Jun. 11, 2015 which claims the benefit of U.S. Provisional Patent Application Ser. No. 62/010,938 filed on Jun. 11, 2014, all of which are hereby incorporated herein by reference. 
     This application is related to the following co-pending United States patent applications, which are hereby incorporated herein by reference: 
     U.S. patent application Ser. No. 14/737,179 entitled “BIT EFFICIENT TRANSPORT THROUGH DISTRIBUTED ANTENNA SYSTEMS” filed on Jun. 11, 2015 (issued in U.S. Pat. No. 9,596,322); 
     U.S. patent application Ser. No. 09/649,159 entitled “METHODS AND SYSTEMS FOR COMMUNICATING IN A CELLULAR NETWORK” filed on Aug. 28, 2000 (issued in U.S. Pat. No. 6,836,660) and which is referred to herein as the &#39;159 application; and 
     U.S. patent application Ser. No. 12/372,319 entitled “DISTRIBUTED ANTENNA SYSTEM USING GIGABIT ETHERNET PHYSICAL LAYER DEVICE” filed on Feb. 17, 2009 (published as U.S. 2010/0208777) and which is referred to herein as the &#39;319 application. 
    
    
     BACKGROUND 
     Distributed Antenna Systems (DAS) are used to distribute wireless signal coverage into buildings or other substantially closed environments. For example, a DAS may distribute antennas within a building. The antennas are typically connected to a radio frequency (RF) signal source, such as a service provider. Various methods of transporting the RF signal from the RF signal source to the antenna have been implemented in the art. 
     SUMMARY 
     An antenna unit includes a transport Layer 1 processor configured to receive a downlink transport Layer 1 data stream from an upstream device and to convert the downlink transport Layer 1 data stream into downlink transport Layer 2 protocol data units in a downlink transport Layer 2; a Layer 2 processor configured to convert the downlink transport Layer 2 protocol data units in the downlink transport Layer 2 into downlink radio access technology Layer 2 protocol data units in a radio access technology Layer 2; a radio access technology Layer 1 processor configured to generate a downlink radio access technology Layer 1 signal from the downlink radio access technology Layer 2 protocol data units in the radio access technology Layer 2; and a radio frequency conversion module configured to convert the downlink radio access technology Layer 1 signal into radio frequency signals for communication using an antenna. 
    
    
     
       DRAWINGS 
       Understanding that the drawings depict only exemplary embodiments and are not therefore to be considered limiting in scope, the exemplary embodiments will be described with additional specificity and detail through the use of the accompanying drawings, in which: 
         FIGS. 1A-1D  are block diagrams of exemplary embodiments of distributed antenna systems; 
         FIGS. 2A-2B  are block diagrams of exemplary embodiments of host units used in distributed antenna systems, such as the exemplary distributed antenna systems in  FIGS. 1A-1B ; 
         FIGS. 3A-3J  are block diagrams of exemplary embodiments of host network interfaces used in host units of distributed antenna systems, such as the exemplary distributed antenna hosts in  FIGS. 2A-2B ; 
         FIGS. 4A-4B  are block diagrams of exemplary embodiments of antenna units used in distributed antenna systems, such as the exemplary distributed antenna systems in  FIGS. 1A-1D ; 
         FIGS. 5A-5D  are block diagrams of exemplary embodiments of RF conversion modules used in antenna units of distributed antenna systems, such as exemplary antenna units in  FIGS. 4A-4B ; 
         FIG. 6  is a block diagram of an exemplary embodiment of a radio access (RAN) network interface used in distributed antenna systems, such as the exemplary distributed antenna systems in  FIGS. 1A-1D . 
         FIG. 7  is a flow diagram illustrating an exemplary embodiment of a method for efficiently transporting wireless network information through a distributed antenna system. 
         FIG. 8  is a flow diagram illustrating another exemplary embodiment of a method for efficiently transporting wireless network information through a distributed antenna system. 
         FIG. 9  is a representation of an exemplary Layer 1 (L1)/Layer 2 (L2) protocol stack for a radio access network (RAN). 
         FIGS. 10A-10B  are block diagrams showing interaction in an exemplary system of various levels of a protocol stack, such as the protocol stack shown in  FIG. 9 . 
     
    
    
     In accordance with common practice, the various described features are not drawn to scale but are drawn to emphasize specific features relevant to the exemplary embodiments. Like reference numbers and designations in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific illustrative embodiments. However, it is to be understood that other embodiments may be utilized and that logical, mechanical, and electrical changes may be made. Furthermore, the method presented in the drawing figures and the specification is not to be construed as limiting the order in which the individual steps may be performed. The following detailed description is, therefore, not to be taken in a limiting sense. 
     The embodiments described below describe a distributed antenna system (DAS) and components within the distributed antenna system (DAS). The distributed antenna system is connected to at least one radio access network (RAN) through at least one radio access network (RAN) interface. In exemplary embodiments, the distributed antenna system includes a distributed antenna system host that interfaces with the at least one radio access network (RAN) interface and converts wireless network information to a more efficient format for transport across at least one medium to at least one antenna unit that converts the wireless network information to a radio frequency signal and communicates it wirelessly using at least one antenna. More specifically, in some embodiments medium access control (MAC) protocol data units (PDUs) are transported instead of baseband IQ samples because the wireless network information is more efficiently transported in MAC PDUs than baseband IQ samples. The ability to transmit the wireless network information in MAC PDUs more efficiently than the baseband IQ samples enables lower bandwidth media to be used, such as Category building cabling such as Category 5, Category 5e, Category 6, Category 6A and Category 7. The ability to transmit the MAC PDUs more efficiently than the baseband IQ samples is essentially a compression technique that enables more data to transmitted over the media. In exemplary embodiments, synchronization information, timing information, power level, signal gain and/or other additional overhead is transmitted in addition to the wireless network information. In exemplary embodiments, wireless network information (or cellular network information) is represented in different ways by the different protocol layers. The wireless network information is the same, but it is formatted differently using different headers, control words, error control bits, etc. that are added/removed by the different protocol layers throughout the entire system. While described using the term distributed antenna system (DAS) herein, it is understood that this description also applies to other wireless distribution technologies and networks, such as distributed base stations, remote radio heads, and/or a centralized radio access network (CRAN, also known as Cloud-RAN and coordinated RAN). In exemplary embodiments, the antenna unit is embodied as a remote radio head. In exemplary embodiments, the radio access network interface is embodied as a baseband unit in a distributed base station and/or a centralized radio access network (CRAN). 
     In exemplary embodiments, radio access technologies may operate using various wireless protocols and in various bands of frequency spectrum. The systems and methodologies described herein apply equally to a number of radio access technologies (RAT), though it is more beneficial for radio access technologies (RAT) that are substantially less efficient with bandwidth at one layer than another. For example, the radio access technologies (RAT) may include, but are not limited to, 800 MHz cellular service, 1.9 GHz Personal Communication Services (PCS), Specialized Mobile Radio (SMR) services, Enhanced Special Mobile Radio (ESMR) services at both 800 MHz and 900 MHz, 1800 MHz and 2100 MHz Advanced Wireless Services (AWS), 700 MHz uC/ABC services, two way paging services, video services, Public Safety (PS) services at 450 MHz, 900 MHz and 1800 MHz Global System for Mobile Communications (GSM), 2100 MHz Universal Mobile Telecommunications System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX), 3rd Generation Partnership Projects (3GPP) Long Term Evolution (LTE), High Speed Packet Access (HSPA), or other appropriate communication services. The system described herein are capable of transporting both Single Input Single Output (SISO) and Multiple Input Multiple Output (MIMO) services at any of the frequencies described above. The systems described herein can support any combination of SISO and MIMO signals across various bands of frequency spectrum. In some example embodiments, the systems described herein may provide MIMO streams for WiMAX, LTE, and HSPA services while only providing SISO streams for other services. Other combinations of MIMO and SISO services are used in other embodiments. 
     Generally, the ability to switch from one layer to another within a particular protocol may afford more efficient use of bandwidth and can be applied to various radio access technologies having various layers, including radio link control (RLC) layers, medium access control (MAC) layers, and physical layers. LTE benefits substantially from a conversion from the physical layer to the MAC layer for transport through a DAS because the physical layer is much less efficient with bits than the MAC layer. 
     In exemplary embodiments, the medium access control (MAC) protocol data units (PDUs) are recovered by undoing the LTE physical layer processing (or other physical layer processing, such as another radio access technology&#39;s physical layer processing) done by the radio access network (RAN) interface (such as an eNodeB) and extracting just the LTE media access protocol (MAC) protocol data units (PDUs). In exemplary embodiments, this conversion to MAC PDUs and back essentially acts as a transport compression and transport decompression system. 
       FIGS. 1A-1D  are block diagrams of exemplary embodiments of distributed antenna systems  100 . Each of  FIGS. 1A-1B  illustrates a different embodiment of a distributed antenna system  100 , labeled  100 A- 100 B respectively. 
       FIG. 1A  is a block diagram of an exemplary embodiment of a distributed antenna system  100 , distributed antenna system  100 A. Distributed antenna system  100 A includes a host unit  102  and at least one antenna unit  104  (including antenna unit  104 - 1  and any quantity of optional antenna units  104  through optional antenna unit  104 -A) communicatively coupled to the host unit  102  through at least one digital communication link  106  (including digital communication link  106 - 1  and any quantity of optional digital communication links  106  through optional digital communication link  106 -A). In exemplary embodiments, the at least one antenna unit  104  is remotely located from the host unit  102 . 
     The host unit  102  is communicatively coupled to at least one radio access network (RAN) interface  108  (including radio access network (RAN) interface  108 - 1  and any quantity of optional radio access network (RAN) interfaces  108  through optional radio access network (RAN) interface  108 -B). In the forward path, the host unit  102  is configured to receive wireless network information from each of the at least one radio access network (RAN) interface  108 . As described in more detail below, the host unit  102  is configured to convert wireless network information from each of the at least one radio access network (RAN) interface  108  into a more efficient format (such as to DAS MAC PDUs from baseband IQ pairs) for transport (either directly or through other components of the distributed antenna system  100 A) to the at least one antenna unit  104  across the at least one digital communication link  106 . 
     Similarly in the reverse path, in exemplary embodiments the host unit  102  is configured to receive uplink data streams formatted in a more efficient format (such as DAS MAC PDUs) across a respective digital communication link  106  from at least one antenna unit  104 . In exemplary embodiments, the host unit  102  is further configured to combine multiple received uplink data streams formatted in the more efficient format (such as DAS MAC PDUs) into a single aggregate uplink data stream formatted in the more efficient format (such as DAS MAC PDUs). In exemplary embodiments, the multiple received uplink data streams are combined using summation (either digital or analog), weighted summation, averaging, multiplexing, etc. The host unit  102  is further configured to convert the received uplink data stream (or the aggregate uplink data stream) formatted in the more efficient format (such as DAS MAC PDUs) to signals formatted for the associated radio access network (RAN) interface  108  (such as baseband IQ samples) and further configured to communicate the signals formatted for the associated radio access network (RAN) interface  108  to the associated radio access network (RAN) interface  108 . 
     Each antenna unit  104  is communicatively coupled to the host unit  102  across a digital communication link  106 . Specifically, antenna unit  104 - 1  is communicatively coupled to the host unit  102  across digital communication link  106 - 1  and optional antenna unit  104 -A is communicatively coupled to the host unit  102  across digital communication link  106 -A. In exemplary embodiments, some or all of the digital communication links  106  are wired digital communication links, such as fiber optic cabling, coaxial cabling, twisted pair cabling, etc. In exemplary embodiments, some or all of the digital communication links  106  are wireless digital communication links. In exemplary embodiments, a synchronous data stream using Ethernet PHY components is communicated across the digital communication links  106 , rather than packetized data, such as traditional Internet Protocol (IP) packets. In exemplary embodiments, the same hardware found in normal packetized Internet Protocol (IP) transport is used, it is just not wrapped into Internet Protocol (IP) packets. Each antenna unit  104  includes components for converting the wireless network information from the more efficient format (such as DAS MAC PDUs) for transport across the at least one digital communication link  106  to radio frequency, for transmission wirelessly using the at least one antenna  110 . 
     In the forward/downstream path, each antenna unit  104  is configured to convert at least one wireless network information from the more efficient format (such as DAS MAC PDUs) to a downlink radio frequency (RF) signal in a radio frequency band for transmission wirelessly using the at least one antenna  110 . In exemplary embodiments, this may include protocol layer processors, converters, and/or translators, digital to analog converters, and oscillators described in more detail below. Each antenna unit  104  is further configured to transmit the downlink radio frequency signal in the radio frequency band to at least one subscriber unit  112  (including subscriber unit  112 - 1  and any quantity of optional subscriber units  112  through optional subscriber unit  112 -D) using at least one antenna  110 . In exemplary embodiments, at least one antenna unit  104 - 1  is configured to transmit one downlink radio frequency signal to one subscriber unit  112 - 1  using an antenna  110 - 1  and another radio frequency signal to another subscriber unit  112 -D using another antenna  110 -C. In exemplary embodiments, other combinations of radio frequency antennas  110  and other components are used to communicate other combinations of radio frequency signals in other various radio frequency bands to various subscriber units  112 . 
     Similarly in the reverse/upstream path, in exemplary embodiments each antenna unit  104  is configured to receive an uplink radio frequency (RF) signal from at least one subscriber unit  112  using at least one antenna  110 . Each antenna unit  104  is further configured to convert the radio frequency signals to at least one uplink data stream. Each antenna unit  104  is further configured to convert wireless network information from the uplink radio frequency signals to a more efficient format (such as DAS MAC PDUs) for transmission across the at least one digital communication link  106  to the host unit  102 . In exemplary embodiments, this may include oscillators, digital to analog converters, and protocol layer converters and/or translators described in more detail below. 
     In exemplary embodiments, a master reference clock is distributed between the various components of the distributed antenna system  100 A to keep the various components locked to the same clock. In exemplary embodiments, the master reference clock is generated based on a signal received from the at least one radio access network interface  108 - 1 . In exemplary embodiments, the master reference clock is generated within another component of the distributed antenna system, such as an antenna unit  104 . 
       FIG. 1B  is a block diagram of an exemplary embodiment of a distributed antenna system  100 , distributed antenna system  100 B. Distributed antenna system  100 B includes a host unit  102  and at least one antenna unit  104  (including antenna unit  104 - 1  and any quantity of optional antenna units  104  through optional antenna unit  104 -A). Distributed antenna system  100 B includes similar components to distributed antenna system  100 A and operates according to similar principles and methods as distributed antenna system  100 A described above. The difference between distributed antenna system  100 B and distributed antenna system  100 A is that distributed antenna system  100 B includes a distributed switching network  114 . Distributed switching network  114  couples the host unit  102  with the at least one antenna unit  104 . Distributed switching network  114  may include one or more distributed antenna switches (such as a DAS expansion host and/or an Ethernet switch) or other intermediary components/nodes that functionally distribute downlink signals from the host unit  102  to the at least one antenna unit  104 . Distributed switching network  114  also functionally distributes uplink signals from the at least one antenna unit  104  to the host unit  102 . In exemplary embodiments, the distributed switching network  114  can be controlled by a separate controller or another component of the system. In exemplary embodiments the switching elements of the distributed switching network  114  are controlled either manually or automatically. In exemplary embodiments, the routes can be pre-determined and static. In other exemplary embodiments, the routes can dynamically change based on time of day, load, or other factors. 
     Each antenna unit  104  is communicatively coupled to the distributed switching network  114  across a digital communication link  116 . Specifically, antenna unit  104 - 1  is communicatively coupled to the distributed switching network  114  across digital communication link  116 - 1  and optional antenna unit  104 -A is communicatively coupled to the distributed switching network  114  across digital communication link  116 -A. In exemplary embodiments, some or all of the digital communication links  116  are wired digital communication links, such as fiber optic cabling, coaxial cabling, twisted pair cabling, etc. In exemplary embodiments, some or all of the digital communication links  116  are wireless digital communication links. In exemplary embodiments, each antenna unit  104  includes components configured for extracting at least one downlink data stream from an aggregate downlink data stream and components configured for aggregating at least one uplink data stream into an aggregate uplink data stream as well as at least one radio frequency converter configured to convert between at least one data stream and at least one radio frequency band and at least one antenna  110  configured to transmit and receive signals in the at least one radio frequency band to at least one subscriber unit  112 . 
       FIG. 1C  is a block diagram of an exemplary embodiment of a distributed antenna system  100 , distributed antenna system  100 C. Distributed antenna system  100 C includes at least one radio access network interface  108  (such as radio access network interface  108 - 1  and any quantity of optional radio access network interfaces  108  through optional radio access network interface  108 -B) and at least one antenna unit  104  (including antenna unit  104 - 1  and any quantity of optional antenna units  104  through optional antenna unit  104 -A). Distributed antenna system  100 C includes some components similar to components of distributed antenna system  100 A and operates according to similar principles and methods as distributed antenna system  100 A described above. The difference between distributed antenna system  100 C and distributed antenna system  100 A is that distributed antenna system  100 C does not include a host unit  102  and the at least one radio access network interface  108  transports using the more efficient format directly to the at least one antenna units  104 . The at least one radio access network interface  108  is communicatively coupled to the at least one antenna unit  104 . In exemplary embodiments, a single radio access network interface  108  is communicatively coupled to a plurality of antenna units  104 . In other exemplary embodiments, a plurality of radio access network interfaces  108  are communicatively coupled to a single antenna unit  104 . 
     In exemplary embodiments of the forward path, the at least one radio access network (RAN) interface  108  is configured to transport (either directly or through other components of the distributed antenna system  100 C) the more efficient format (such as DAS MAC PDUs) to the at least one antenna unit  104  across the at least one digital communication link  106 , rather than having a host unit  102  convert to the more efficient format (such as DAS MAC PDUs) from a less efficient format (such as baseband IQ pairs). Similarly in exemplary embodiments of the reverse path, the at least one radio access network (RAN) interface  108  is configured to receive (either directly or through other components of the distributed antenna system  100 C) the more efficient format (such as DAS MAC PDUs) from the at least one antenna unit  104  across the at least one digital communication link  106 , rather than having a host unit convert from the more efficient format (such as DAC MAC PDUs) to the less efficient format (such as baseband IQ pairs) in-between the radio access network interface  108  and the antenna unit  104 . 
     Each antenna unit  104  is communicatively coupled to the at least one radio access network interface  108  across a digital communication link  106 . Specifically, antenna unit  104 - 1  is communicatively coupled to the radio access network interface  108 - 1  across digital communication link  106 - 1  and optional antenna unit  104 -A is communicatively coupled to the radio access network interface  108 -B across digital communication link  106 -A. In exemplary embodiments, some or all of the digital communication links  106  are wired digital communication links, such as fiber optic cabling, coaxial cabling, twisted pair cabling, etc. In exemplary embodiments, some or all of the digital communication links  106  are wireless digital communication links. Each antenna unit  104  includes components for converting, in the forward path, the wireless network information from the more efficient format (such as DAS MAC PDUs) for transport across the at least one digital communication link  106  to radio frequency, for transmission wirelessly using the at least one antenna  110 . Each antenna unit  104  also includes components for converting, in the reverse path, the wireless network information from radio frequency received wirelessly using the at least one antenna  110  to the more efficient format (such as DAS MAC PDUs) for transport across the at least one digital communication link  106  to the at least one radio access network interface  108 . 
       FIG. 1D  is a block diagram of an exemplary embodiment of a distributed antenna system  100 , distributed antenna system  100 D. Distributed antenna system  100 D includes at least one radio access network interface  108  (including radio access network interface  108 - 1  and any quantity of optional radio access network interfaces  108  through optional radio access network interfaces  108 -B) and at least one antenna unit  104  (including antenna unit  104 - 1  and any quantity of optional antenna units  104  through optional antenna unit  104 -A). Distributed antenna system  100 D includes similar components to distributed antenna system  100 C and operates according to similar principles and methods as distributed antenna system  100 C described above. The difference between distributed antenna system  100 D and distributed antenna system  100 C is that distributed antenna system  100 D includes a distributed switching network  114 . Distributed switching network  114  couples the at least one radio access network interface  108  with the at least one antenna unit  104 . Distributed switching network  114  may include one or more distributed antenna switches (such as a DAS expansion unit and/or an Ethernet switch) or other intermediary components/nodes that functionally distribute downlink signals from the at least one radio access network interface  108  to the at least one antenna unit  104 . Distributed switching network  114  also functionally distributes uplink signals from the at least one antenna unit  104  to the at least one radio access network interface  108 . In exemplary embodiments, the distributed switching network  114  can be controlled by a separate controller or another component of the system. In exemplary embodiments the switching elements of the distributed switching network  114  are controlled either manually or automatically. In exemplary embodiments, the routes can be pre-determined and static. In other exemplary embodiments, the routes can dynamically change based on time of day, load, or other factors. 
     Each antenna unit  104  is communicatively coupled to the distributed switching network  114  across a digital communication link  116 . Specifically, antenna unit  104 - 1  is communicatively coupled to the distributed switching network  114  across digital communication link  116 - 1  and optional antenna unit  104 -A is communicatively coupled to the distributed switching network  114  across optional digital communication link  116 -A. In exemplary embodiments, some or all of the digital communication links  116  are wired digital communication links, such as fiber optic cabling, coaxial cabling, twisted pair cabling, etc. In exemplary embodiments, some or all of the digital communication links  116  are wireless digital communication links. In exemplary embodiments, each antenna unit  104  includes components configured for extracting at least one downlink data stream from an aggregate downlink data stream and components configured for aggregating at least one uplink data stream into an aggregate uplink data stream as well as at least one radio frequency converter configured to convert between at least one data stream and at least one radio frequency band and at least one antenna  110  configured to transmit and receive signals in the at least one radio frequency band to at least one subscriber unit  112 . 
       FIGS. 2A-2B  are block diagrams of exemplary embodiments of host unit  102 . Each of  FIGS. 2A-2B  illustrates a different embodiment of a host unit  102 , labeled  102 A- 102 B respectively. 
       FIG. 2A  is a block diagram of an exemplary embodiment of a host unit  102 , host unit  102 A, used in distributed antenna systems, such as the exemplary distributed antenna systems  100  described above. Exemplary host unit  102 A includes at least one host network interface  202  (including host network interface  202 - 1  and any quantity of optional host network interfaces  202  through optional host network interface  202 -B), at least one physical layer processor  204  (including physical layer processor  204 - 1  and any quantity of optional physical layer processors  204  through optional physical layer processor  204 -B), a distributed antenna system (DAS) medium access control (MAC) layer processor  206 , a distributed antenna system (DAS) transport physical layer processor  208 , an optional master host clock unit  210 , an optional processor  212 , optional memory  214 , and an optional power supply  216 . In exemplary embodiments, the at least one physical layer processor  204  is a radio access technology (RAT) physical layer processor, such as an LTE physical layer processor or another type of RAT physical layer processor. In exemplary embodiments, the DAS transport physical layer processor  208  is an Ethernet physical layer processor. In other embodiments, the DAS transport physical layer processor  208  is another type. In exemplary embodiments, the host network interfaces  202 , the physical layer processors  204 , the distributed antenna system medium access control layer processor  206 , the DAS transport physical layer processor  208  and/or master host clock unit  210  are implemented in whole or in part by optional processor  212  and memory  214 . In exemplary embodiments, power supply  216  provides power for the various components of the host unit  102 A. In exemplary embodiments, the physical layer processors  204  are LTE physical layer processors because the signals received from the corresponding host network interfaces  202  are LTE physical layer signals. In exemplary embodiments, some of the physical layer processors  204  are physical layer processors for radio access technologies other than LTE and the physical layer signals received from the corresponding host network interfaces  202  are for these other radio access technologies. In exemplary embodiments, no physical layer processors  204  are included with some corresponding host network interfaces  202  that receive signals that are not physical layer signals. In exemplary embodiments, combinations of LTE physical layer processors  204 , other radio access technology physical layer processors  204 , and no physical layer processors  204  are included in host unit  102 A. In exemplary embodiments, the host unit  102  provides/distributes power to at least a first of the at least one antenna unit  104 . 
     In the forward path, each host network interface  202  receives downlink wireless network information transported in another format from a respective radio access network interface  108  and converts the downlink wireless network information from the another format to the baseband downlink wireless network information type. In exemplary embodiments, the purpose of the host network interface  202  is to convert the data form the format used by the base station into a format acceptable to the RAT physical layer processor  204 . In exemplary embodiments, at least some of the host network interfaces  202  communicate using digital signals with the radio access network interfaces  108 . In exemplary embodiments, at least some of the host network interfaces  202  communicate using analog signals (such as radio frequency (RF) and/or intermediate frequency (IF) analog signals) with the radio access network interfaces  108 . In exemplary embodiments, a host network interface  202  is connected to an analog radio access network interface  108 , such as a small cell, and the host exchanges analog RF with the analog radio access network interface  108  and the host  102 A includes a digital front end (such as within the host network interface  202  or between the host network interface  202  and the RAT physical layer processor  204 ) to convert between the RF and the stream of bits exchanged with the RAT physical layer processor  204 . 
     In specific implementations, at least one host network interface  108  receives Common Public Radio Interface (CPRI) signals from a CPRI interface of a base band unit acting as the radio access network interface  108 , converts the CPRI signals into a format compatible with the RAT physical layer processor. In one embodiment of a CPRI interface, the data is in an LTE PHY format and has already been coded, modulated, and fully processed according to the LTE PHY specifications. It is an I/Q stream coming from the radio access network interface  108 . The LTE PHY processor (RAT physical layer processor  204 - 1 ) in the host unit  102 A would basically undo the LTE PHY processing that was done by the BBU (radio access network interface  108 ). The LTE physical layer data (RAT physical layer data) is translated into the LTE MAC PDUs (RAT MAC PDUs) by the LTE PHY processor (RAT physical layer processor  204 ). The DAS MAC (transport medium access control (MAC) processor  206 ), which may be implemented as an FPGA, determines what to do with these LTE MAC PDUs (RAT MAC PDUs) including how to frame them, format them, and put them into their own structure that is required for transport over the digital communication medium  106  (such as Category building cable or other lower bandwidth cable). 
     In the reverse path, each host network interface  202  receives uplink wireless network information in the RAT physical format and converts them into a format for communication with the respective radio access network interface  108 . In specific implementations, at least one host network interface  108  receives uplink physical layer data signals and converts the uplink physical layer data signals into uplink CPRI signals and communicates the CPRI signals to the at least one radio access network interface  108 . 
     In the forward path, each physical layer processor  204  receives downlink physical layer data signals and converts the downlink physical layer data signals in the physical layer to downlink medium access control (MAC) layer protocol data units (PDUs) in the medium access control (MAC) layer, wherein the medium access control layer uses relevant bits more efficiently than the physical layer. In the reverse path, each physical layer processor  204  receives uplink RAT MAC layer protocol data units in the RAT MAC layer and converts the uplink RAT MAC layer PDUs to uplink physical layer data signals. 
     In exemplary embodiments, the physical layer processor  204  in the host unit  102  performs functions similar to a user equipment (UE) device in that it receives the RAT physical signals and reverses the physical processor performed by the radio access network. In the uplink the physical layer processor  204  in the host unit  102  creates an uplink physical signal representation of the wireless network information such that the radio access network to which the host unit  102  is connected through the radio access network interface  108  can perform its normal uplink processing. In exemplary embodiments, the DAS processing is transparent to the radio access network interface  108  and the radio access network generally as well as the user equipment (UE). 
     In the forward path, the DAS MAC layer processor  206  converts the downlink RAT MAC PDUs in the RAT MAC into downlink distributed antenna system (DAS) transport medium access control (MAC) layer protocol data units (PDUs) in a downlink distributed antenna system (DAS) transport medium access control (MAC) layer for transport through the distributed antenna system (DAS). In the reverse path, the DAS MAC layer processor  206  converts the uplink distributed antenna system (DAS) transport medium access control (MAC) layer protocol data units (PDUs) in an uplink distributed antenna system (DAS) transport medium access control (MAC) layer into uplink medium access control (MAC) layer protocol data units (PDUs) in the medium access control (MAC) layer. In exemplary embodiments, the DAS MAC layer processor  206  also broadcasts signals to a plurality of different remote antenna units  104 . In exemplary embodiments, the DAS MAC layer processor  206  also combines uplink DAS transport MAC layer PDUs from different antenna units  104  in an intelligent way. In exemplary embodiments, multiple received uplink data streams are combined using summation (either digital or analog), weighted summation, averaging, multiplexing, etc. In exemplary embodiments, combining in the upstream occurs by recovering the RAT MAC PDUs (such as LTE MAC PDUs) for all the signals to be combined and then having a plurality of RAT physical layer processors  204  (such as LTE PHY processors) individually process the signals from RAT MAC PDUs (such as LTE MAC PDUs) into I/Q samples, which are then digitally combined in a combiner that may be within a host network interface  202  or in between the RAT physical layer processors  204  and a host network interface  202 . In other embodiments, the DAS MAC PDUs from the multiple remote units  104  are combined bitwise by the DAS MAC processor  206 . In exemplary embodiments, the combining is done through majority logic and/or weighted combining. In exemplary embodiments, all the signals need to be synchronized so the host unit  102 A knows which bit goes with which bit and so the combining results in accurate data. In exemplary embodiments, the antenna units  104  are synchronized with the host unit  102 . In exemplary embodiments, the DAS MAC layer processor  206  determines whether multiple antenna units  104  received signals from a particular remote/subscriber unit  112  and whether there is valid data coming from multiple antenna units  104 . If there is valid data coming from multiple antenna units  104 , the DAS MAC layer processor  206  will combine the bits. Because there are RAT physical layer processors  406  (such as LTE PHY processors) at the antenna units  104  (described below), the RAT physical layer processors  406  at the antenna units  104  could generate quality measurements, such as a signal to noise ratio (SNR), modulation quality, etc. and then feedback the quality metrics to the host unit  102 A to use in weighing and combining of the signals. 
     In the forward path, the DAS transport physical layer processor  208  converts the downlink DAS transport MAC layer PDUs in the downlink DAS transport MAC layer into downlink DAS physical layer data streams in the DAS physical layer and communicates the downlink DAS physical layer data streams across the at least one digital communication medium  106  to the at least one antenna unit  104 . In the reverse path, the DAS transport physical layer processor  208  receives uplink DAS physical layer data streams in the DAS physical layer from the at least one digital communication medium  106  and converts the uplink DAS physical layer data streams into uplink DAS transport MAC layer PDUs in the uplink DAS transport MAC layer. 
     In exemplary embodiments, the antenna units  104  are synchronized with each other and/or the host unit  102 . In exemplary embodiments, the antenna units  104  and/or the host unit  102  are synchronized based on a clock signal propagated from the host unit  102  that is generated from a signal received by the host unit  102  from the radio access network interface  108  (such as a baseband unit BBU and/or small cell) so the network synchronization of the radio access network interface  108  (such as a baseband unit BBU and/or small cell) is propagated through to the various components of the distributed antenna system  100 . In exemplary embodiments, the master host clock unit  210  extracts the master reference clock from a signal supplied by at least one radio access network interface  108 . In exemplary embodiments, the master clock unit  210  distributes the master reference clock to other components of the distributed antenna system  100  in the downlink. In exemplary embodiments, the master host clock unit  210  distributes this master clock with other radio access network interfaces  108  through the corresponding host network interfaces  202 . In exemplary embodiments (such as those where the radio access network interface is an analog radio frequency interface), the master host clock unit  210  generates a master reference clock and distributes the generated master reference clock with radio access network interfaces  108  through the corresponding host network interfaces  202 . 
       FIG. 2B  is a block diagram of an exemplary embodiment of a host unit  102 , host unit  102 B, used in distributed antenna systems, such as the exemplary distributed antenna systems  100  described above. Exemplary host unit  102 B includes at least one host network interface  202  (including host network interface  202 - 1  and any quantity of optional host network interfaces  202  through optional host network interface  202 -B), a distributed antenna system (DAS) medium access control (MAC) layer processor  206 , an DAS transport physical layer processor  208 , an optional master host clock unit  210 , an optional processor  212 , optional memory  214 , and an optional power supply  216 . In exemplary embodiments, the host network interfaces  202 , the DAS MAC layer processor  206 , the DAS transport physical layer processor  208  and/or master host clock unit  210  are implemented in whole or in part by optional processor  212  and memory  214 . In exemplary embodiments, power supply  216  provides power for the various components of the host unit  102 B. Host unit  102 B includes similar components to host unit  102 A and operates according to similar principles and methods as host unit  102 A described above. 
     The difference between host unit  102 B and host unit  102 A is that host unit  102 B does not include any RAT physical layer processors  204 . In exemplary embodiments, the LTE PHY processor (RAT physical layer processor  204 ) is not necessary in the host unit  102 A because the host unit  102 A receives the LTE MAC PDUs (RAT MAC PDUs) directly from the baseband unit (BBU, such as radio access network interface  108 ). In exemplary embodiments, this may require changes to the baseband unit (BBU, such as radio access network interface  108 ) to allow output of the LTE MAC PDUs (RAT MAC PDUs) instead of the I/Q stream. In exemplary embodiments, the RAT physical layer processor  204  is not included and/or bypassed with some signals so that I/Q samples are transmitted through the distributed antenna system  100  instead of the MAC PDUs. In exemplary embodiments, this is useful with other radio access technologies (RAT) that do not require as much bandwidth for transport using I/Q baseband samples as LTE. Accordingly, I/Q samples could be packed into a DAS physical layer compatible frame. In exemplary embodiments, this enables data represented in IQ space to be transported directly instead of translating it into the MAC PDUs for transport. The benefit of this approach is that the distributed antenna system  100  can be radio access technology (RAT) agnostic. This could be more useful with less bandwidth hungry wireless access technology protocols, such as 2G and/or 3G radio access technologies (RAT). In exemplary embodiments, this approach is less complicated because it does not require the additional LTE PHY processors in both the host unit  102  and antenna units  104 . In exemplary embodiments, some signals go through a RAT physical layer processor  204  and are converted into MAC PDUs, while others remain as I/Q samples, but all the signals can be multiplexed together and transported through the distributed antenna system  100 . This enables inputs from different sources to be used while sharing a single cable. In exemplary embodiments, there is some framing within the payload with both MAC PDUs and synchronous I/Q samples. 
     Accordingly and in the forward path, the DAS MAC layer processor  206  converts the downlink RAT MAC data signals in the MAC layer into downlink distributed antenna system (DAS) transport medium access control (MAC) layer protocol data units (PDUs) in a downlink distributed antenna system (DAS) transport medium access control (MAC) layer for transport through the distributed antenna system (DAS). In the reverse path, the DAS MAC layer processor  206  converts the uplink distributed antenna system (DAS) transport medium access control (MAC) layer protocol data units (PDUs) in an uplink distributed antenna system (DAS) transport medium access control (MAC) layer into RAT MAC layer data signals in the MAC layer. This host unit  102 B could be used in exemplary embodiments where the radio access network interface  108  communicates RAT MAC PDUs directly with the host network interface  202 , so it is not necessary to perform any physical RAT layer processing to get the wireless network information into the more efficient format. This host unit  102 B could also be used in exemplary embodiments where it is not necessary to undo any physical RAT layer processing even though the signals received from the radio access network interface  108  have had physical RAT layer processing, because the physical RAT layer processing is efficient enough. In exemplary embodiments, combinations of host unit  102 A and host unit  102 B allow for some wireless network information to have the physical RAT layer processing undone using a physical layer processor and others to not have it undone, so a physical layer processor  204  is not necessary. 
       FIGS. 3A-3J  are block diagrams of exemplary embodiments of base station host network interfaces  302  used in distributed antenna systems, such as the exemplary distributed antenna systems  100  described above. Each of  FIGS. 3A-3J  illustrates a different embodiment of a type of host network interface  202 , labeled  104 A- 104 D respectively. 
       FIG. 3A  is a block diagram of an exemplary embodiment of a host network interface  202 , general host network interface  202 A. General host network interface  202 A includes signal to data stream conversion module  302 A, network interface clock unit  304 A, optional processor  306 , optional memory  308 , and optional power supply  310 . In exemplary embodiments, signal to data stream conversion module  302 A is communicatively coupled to a radio access network interface output  312 A of a radio access network interface  108 A. Signal to data stream conversion module  302 A is also communicatively coupled to at least physical layer processor  204 . In exemplary embodiments, the signal to data stream conversion module  302 A and/or the network interface clock unit  304 A are implemented using optional processor  306  and optional memory  308 . In exemplary embodiments, the optional power supply  310  provides power to the various elements of the host network interface  202 A. 
     In the downlink, signal to data stream conversion module  302 A is configured to receive downlink signals from the radio access network interface output  312 A of the radio access network interface  108 A. The signal to data stream conversion module  302 A is further configured to convert the received downlink signals to a downlink data stream. In the uplink, signal to data stream conversion module  302 A is configured to receive an uplink data stream from an physical layer processor  204 . The signal to data stream conversion module  302 A is further configured to convert the uplink data stream to uplink signals. Signal to data stream conversion module  302 A is further configured to communicate the uplink signals to the radio access network interface output  312 A of the radio access network interface  108 A. 
     In exemplary embodiments, the network interface clock unit  304 A is communicatively coupled to a radio access network interface clock unit  314 A of the radio access network interface  108 A. In exemplary embodiments, a master reference clock is provided from the radio access network interface clock unit  314 A of the radio access network interface  108 A to the network interface clock unit  304 A of the host network interface  202 A. In other exemplary embodiments, a master reference clock is provided to the radio access network interface clock unit  314 A of the radio access network interface  108 A from the network interface clock unit  304 A of the host network interface  202 A. 
       FIG. 3B  is a block diagram of an exemplary embodiment of a type of base station interface  102 , general host network interface  202 B. General host network interface  202 B includes signal to data stream conversion module  302 B, network interface clock unit  304 B, optional processor  306 , optional memory  308 , and optional power supply  310 . Similarly to general host network interface  202 A, signal to data stream conversion module  302 B is communicatively coupled to a radio access network interface output  312 B of a radio access network interface  108 B. In contrast to general host network interface  202 A, base station network interface clock unit  304 B is not coupled directly to radio access network interface clock unit  314 B of radio access network interface  108 B to provide the master reference clock to the network interface clock unit  304 B. Instead, radio access network interface clock unit  314 B provides the master reference clock to the radio access network interface output  312 B and the master reference clock is embedded in the downstream signal from the radio access network interface output  312 B to the signal to data stream conversion module  302 B of the host network interface  202 B, which then provides it to the network interface clock unit  304 B. 
     In exemplary embodiments where the master reference clock is provided from an radio access network interface  108 B to the distributed antenna system  100 , the master reference clock can be embedded in the downlink signals by the radio access network interface clock unit  314 B so that the downlink signals communicated from the radio access network interface output  312 B of the radio access network interface  108 B to the signal to data stream conversion module  302 B can be extracted by the network interface clock unit  304 B and distributed as appropriate within the host network interface  202 B and the distributed antenna system  100  generally. In exemplary embodiments, the signal to data stream conversion module  302 B and/or the network interface clock unit  304 B are implemented using optional processor  306  and optional memory  308 . In exemplary embodiments, the optional power supply  310  provides power to the various elements of the host network interface  202 B. 
       FIG. 3C  is a block diagram of an exemplary embodiment of a type of host network interface  202 , baseband host network interface  202 C. Baseband host network interface  202 C includes a baseband to data stream conversion module  302 C, a baseband network interface clock unit  304 C, an optional processor  306 , optional memory  308 , and an optional power supply  310 . In exemplary embodiments, baseband to data stream conversion module  302 C is communicatively coupled to a baseband base station output  312 C of a radio access network interface that is a baseband base station  108 C. Baseband to data stream conversion module  302 C is also communicatively coupled to at least one physical layer processor  204 . In exemplary embodiments, the baseband to data stream conversion module  302 C and/or the baseband network interface clock unit  304 C are implemented using optional processor  306  and optional memory  308 . In exemplary embodiments, the optional power supply  310  provides power to the various elements of the baseband host network interface  202 C. 
     In the downlink, baseband to data stream conversion module  302 C is configured to receive baseband mobile wireless access signals (such as I/Q data) from a baseband base station output  312 C of a baseband base station  108 C. The baseband to data stream conversion module  302 C is further configured to convert the received baseband mobile wireless access signals to a downlink data stream. In the uplink, baseband to data stream conversion module  302 C is configured to receive a data stream from physical layer processor  204 . The baseband to data stream conversion module  302 C is further configured to convert the uplink data stream to uplink baseband wireless access signals. Baseband to data stream conversion module  302 C is further configured to communicate the uplink baseband wireless access signals to the baseband base station output  312 C. 
     In exemplary embodiments, the baseband network interface clock unit  304 C is communicatively coupled to a baseband base station clock unit  314 C of the baseband base station  108 C. In exemplary embodiments, a master reference clock is provided from the baseband base station clock unit  314 C of the baseband base station  108 C to the baseband network interface clock unit  304 C of the baseband host network interface  202 C. In exemplary embodiments, a master reference clock is provided to the baseband base station clock unit  314 C of the baseband base station  108 C from the baseband network interface clock unit  304 C of the baseband host network interface  202 C. 
       FIG. 3D  is a block diagram of an exemplary embodiment of a type of base station interface  102 , baseband network interface  202 D. Baseband network interface  202 D includes a baseband to data stream conversion module  302 D, a baseband network interface clock unit  304 D, an optional processor  306 , optional memory  308 , and an optional power supply  310 . Similarly to baseband host network interface  202 C, baseband to data stream conversion module  302 D is communicatively coupled to a baseband base station output  312 D of a radio access network interface that is a baseband base station  108 D and to at least one physical layer processor  204 . In contrast to baseband host network interface  202 C, baseband network interface clock unit  304 D is not coupled directly to baseband base station clock unit  314 D of baseband base station  108 D to provide and/or receive the master reference clock to/from the baseband base station  108 D. Instead, baseband base station output  312 D provides the master reference clock to the baseband to data stream conversion module  302 D and the master reference clock is embedded in downstream signals from the baseband base station output  312 D of baseband base station  108 D to the baseband to data stream conversion module  302 D of the baseband network interface  202 D. 
     In exemplary embodiments where the master reference clock is provided from the baseband base station  108 D to the distributed antenna system, the master reference clock can be embedded in the downlink signals by the baseband base station clock unit  314 D so that the downlink signals communicated from the baseband base station output  312 D of the baseband base station  108 D to the baseband to data stream conversion module  302 D can be extracted by the baseband network interface clock unit  304 D and distributed as appropriate within the baseband network interface  202 D and the distributed antenna system generally. In exemplary embodiments, the baseband to data stream conversion module  302 D and/or the baseband network interface clock unit  304 D are implemented using optional processor  306  and optional memory  308 . In exemplary embodiments, the optional power supply  310  provides power to the various elements of the baseband network interface  202 D. 
       FIG. 3E  is a block diagram of an exemplary embodiment of a type of host network interface  202 , Common Public Radio Interface (CPRI) host network interface  202 E. CPRI host network interface  202 E includes a CPRI to data stream conversion module  302 E, a CPRI network interface clock unit  304 E, an optional processor  306 , optional memory  308 , and an optional power supply  310 . In exemplary embodiments, CPRI to data stream conversion module  302 E is communicatively coupled to a CPRI base station output  312 E of a host network interface  202  that is a CPRI base station  108 E. CPRI to data stream conversion module  302 E is also communicatively coupled to at least one physical layer processor  204 . In exemplary embodiments, the CPRI to data stream conversion module  302 E and/or the CPRI network interface clock unit  304 E are implemented using optional processor  306  and optional memory  308 . In exemplary embodiments, the optional power supply  310  provides power to the various elements of the CPRI host network interface  202 E. 
     In the downlink, CPRI to data stream conversion module  302 E is configured to receive CPRI signals from the CPRI base station output  312 E. The CPRI to data stream conversion module  302 E is further configured to convert the received CPRI signals to a downlink data stream. In the uplink, CPRI to data stream conversion module  302 G is configured to receive a data stream from physical layer processor  204 . The CPRI to data stream conversion module  302 E is further configured to convert the uplink data stream to uplink CPRI signals. CPRI to data stream conversion module  302 E is further configured to communicate the uplink CPRI signal to the CPRI base station output  312 E. 
     In exemplary embodiments, the CPRI network interface clock unit  304 E is communicatively coupled to a CPRI base station clock unit  314 E of the CPRI base station  108 E. In exemplary embodiments, a master reference clock is provided from the CPRI base station clock unit  314 E of the CPRI base station  108 E to the CPRI network interface clock unit  304 C of the CPRI host network interface  202 E. In other exemplary embodiments, a master reference clock is provided to the CPRI base station clock unit  314 E of the CPRI base station  108 E from the CPRI network interface clock unit  304 E of the CPRI host network interface  202 E. 
       FIG. 3F  is a block diagram of an exemplary embodiment of a type of base station interface  102 , CPRI host network interface  202 F. CPRI host network interface  202 F includes a CPRI to data stream conversion module  302 F, a CPRI network interface clock unit  304 F, an optional processor  306 , optional memory  308 , and an optional power supply  310 . Similarly to CPRI host network interface  202 E, CPRI to data stream conversion module  302 F is communicatively coupled to a CPRI base station output  312 F of a radio access network interface  108  that is a CPRI base station  108 F and to at least one physical layer processor  204 . In contrast to CPRI host network interface  202 E, CPRI network interface clock unit  304 F is not coupled directly to CPRI base station clock unit  314 E of CPRI base station  108 F to provide and/or receive the master reference clock to/from the CPRI base station  108 F. Instead, CPRI to data stream conversion module  302 F provides the master reference clock to the CPRI host network interface  202 F and the master reference clock is embedded in downstream signals from the CPRI base station output  312 F of the CPRI base station  108 F to the CPRI to data stream conversion module  302 F of CPRI network interface  202 F. 
     In exemplary embodiments where the master reference clock is provided from the CPRI base station  108 F to the distributed antenna system  100 , the master reference clock can be embedded in the downlink signals by the CPRI base station clock unit  314 F so that the downlink signals communicated from the CPRI base station output  312 F of the CPRI base station  108 F to the CPRI to data stream conversion module  302 F can be extracted by the CPRI network interface clock unit  304 F and distributed as appropriate within the CPRI host network interface  202 F and the distributed antenna system  100  generally. In exemplary embodiments, the CPRI to data stream conversion module  302 F and/or the CPRI network interface clock unit  304 F are implemented using optional processor  306  and optional memory  308 . In exemplary embodiments, the optional power supply  310  provides power to the various elements of the CPRI host network interface  202 F. 
       FIG. 3G  is a block diagram of an exemplary embodiment of a type of host network interface  202 , radio frequency (RF) host network interface  202 G. Radio frequency host network interface  202 G includes a radio frequency (RF) to data stream conversion module  302 G, a radio frequency (RF) network interface clock unit  304 G, an optional processor  306 , optional memory  308 , and an optional power supply  310 . In exemplary embodiments, radio frequency (RF) to data stream conversion module  302 G is communicatively coupled to a radio frequency (RF) base station output  312 G of a radio access network interface that is a radio frequency base station  108 G. Radio frequency to data stream conversion module  302 G is also communicatively coupled to at least one physical layer processor  204 . In exemplary embodiments, the radio frequency to data stream conversion module  302 G and/or the radio frequency network interface clock unit  304 G are implemented using optional processor  306  and optional memory  308 . In exemplary embodiments, the optional power supply  310  provides power to the various elements of the radio frequency host network interface  202 G. 
     In the downlink, radio frequency to data stream conversion module  302 G is configured to receive radio frequency signals from the radio frequency base station output  312 G of the radio frequency base station  108 G. The radio frequency to data stream conversion module  302 G is further configured to convert the received radio frequency signals to a downlink data stream. In exemplary embodiments, this is done using oscillators and mixers. In the uplink, radio frequency to data stream conversion module  302 G is configured to receive a data stream from physical layer processor  204 . The radio frequency to data stream conversion module is further configured to convert the uplink data stream to radio frequency signals. In exemplary embodiments, this is done using oscillators and mixers. Radio frequency to data stream conversion module  302 G is further configured to communicate the uplink radio frequency signals to the radio frequency base station output  312 G of the radio frequency base station  108 G. 
     In exemplary embodiments, the radio frequency network interface clock unit  304 G is communicatively coupled to a radio frequency base station clock unit  314 G of the radio frequency base station  108 G. In exemplary embodiments, a master reference clock is provided from the radio frequency base station clock unit  314 G of the radio frequency base station  108 G to the radio frequency network interface clock unit  304 G of the radio frequency host network interface  202 G. In other exemplary embodiments, a master reference clock is provided to the radio frequency base station clock unit  314 G of the radio frequency base station  108 G from the radio frequency network interface clock unit  304 G of the host network interface  202 G. 
       FIG. 3H  is a block diagram of an exemplary embodiment of a type of base station interface  102 , radio frequency (RF) host network interface  202 H. Radio frequency host network interface  202 H includes a radio frequency (RF) to data stream conversion module  202 H, a radio frequency (RF) network interface clock unit  204 H, an optional processor  306 , optional memory  308 , and an optional power supply  310 . Similarly to radio frequency host network interface  202 G, radio frequency (RF) to data stream conversion module  202 H is communicatively coupled to a radio frequency (RF) base station output  212 H of a radio access network interface  108  that is a radio frequency base station  108 H and to at least one physical layer processor  204 . In contrast to radio frequency host network interface  202 G, radio frequency network interface clock unit  204 H is not coupled directly to radio frequency base station clock unit  214 H of radio frequency base station  108 H to provide and/or receive the master reference clock to/from the radio frequency base station  108 H. Instead, radio frequency to data stream conversion module  202 H provides the master reference clock to the radio frequency network interface clock unit  304 G and the master reference clock is embedded in downstream signals from the RF base station output  312 H of the RF base station  108 H to the RF to data stream conversion module  302 H of the RF network interface  202 H. 
     In exemplary embodiments where the master reference clock is provided from the radio frequency base station  108 H to the distributed antenna system, the master reference clock can be embedded in the downlink signals by the radio frequency base station clock unit  214 H so that the downlink signals communicated from the radio frequency base station output  212 H of the radio frequency base station  108 H to the radio frequency to data stream conversion module  202 H can be extracted by the radio frequency network interface clock unit  204 H and distributed as appropriate within the radio frequency host network interface  202 H and the distributed antenna system  100  generally. In exemplary embodiments, the radio frequency to data stream conversion module  202 H and/or the radio frequency network interface clock unit  204 H are implemented using optional processor  306  and optional memory  308 . In exemplary embodiments, the optional power supply  310  provides power to the various elements of the host network interface  202 H. 
       FIG. 3I  is a block diagram of an exemplary embodiment of a type of host network interface  202 , Ethernet network interface  202 I. Ethernet network interface  202 I includes an Ethernet to data stream conversion module  302 I, an Ethernet network interface clock unit  304 I, an optional processor  306 , optional memory  308 , and an optional power supply  310 . In exemplary embodiments, Ethernet to data stream conversion module  302 I is communicatively coupled to an Ethernet output  312 I of an external device that is an Ethernet adapter  108 I to an internet protocol (IP) based network. Ethernet to data stream conversion module  302 I is also communicatively coupled to at least one physical layer processor  204 . In exemplary embodiments, the Ethernet to data stream conversion module  302 I and/or the Ethernet network interface clock unit  304 I are implemented using optional processor  306  and optional memory  308 . In exemplary embodiments, the optional power supply  310  provides power to the various elements of the Ethernet network interface  202 I. 
     In the downlink Ethernet to data stream conversion module  302 I is configured to receive internet protocol packets from the Ethernet output  312 I. The Ethernet to data stream conversion module  302 I is further configured to convert the internet protocol packets to a downlink data stream. In the uplink, Ethernet to data stream conversion module  302 I is configured to receive a data stream from physical layer processor  204 . The Ethernet to data stream conversion module  302 I is further configured to convert the uplink data stream to uplink Ethernet frames. Ethernet to data stream conversion module  302 I is further configured to communicate the uplink Ethernet frames to the Ethernet output  304 I. 
     In exemplary embodiments, the Ethernet network interface clock unit  304 I is communicatively coupled to an Ethernet adapter clock unit  314 I of the Ethernet adapter  108 I. In exemplary embodiments, a master reference clock is provided from the Ethernet adapter clock unit  314 I of the Ethernet adapter  108 I to the Ethernet network interface clock unit  304 I of the Ethernet network interface  202 I. In other exemplary embodiments, a master reference clock is provided to the Ethernet adapter clock unit  314 I of the Ethernet adapter  108 I from the Ethernet network interface clock unit  304 I of the Ethernet network interface  202 I. 
       FIG. 3J  is a block diagram of an exemplary embodiment of a type of base station interface  102 , an Ethernet network interface  202 J. Ethernet network interface  202 J includes an Ethernet to data stream conversion module  302 J, an Ethernet network interface clock unit  304 J, an optional processor  306 , optional memory  308 , and an optional power supply  310 . Similarly to Ethernet network interface  202 I, Ethernet to data stream conversion module  302 J is communicatively coupled to an Ethernet output  312 J of an external device that is an Ethernet adapter  108 J and to at least one physical layer processor  204 . In contrast to Ethernet network interface  202 I, Ethernet network interface clock unit  304 J is not coupled directly to Ethernet adapter clock unit  314 J of Ethernet adapter  108 J to provide and/or receive the master reference clock to/from the Ethernet adapter  108 J. Instead, Ethernet output  312 J provides the master reference clock to the Ethernet to data stream conversion module  302 J and the master reference clock is embedded in downstream signals from the Ethernet output  312 J of the Ethernet adapter  108 J to the Ethernet to data stream conversion module  302 J of the Ethernet network interface  202 J. 
     In exemplary embodiments where the master reference clock is provided from the Ethernet adapter  108 J to the distributed antenna system  100 , the master reference clock can be embedded in the downlink signals by the Ethernet adapter clock unit  314 J so that the downlink signals communicated from the Ethernet output  312 J of the Ethernet adapter  108 J to the Ethernet to data stream conversion module  302 J can be extracted by the Ethernet network interface clock unit  304 J and distributed as appropriate within the Ethernet network interface  202 J and the distributed antenna system  100  generally. In exemplary embodiments, the Ethernet to data stream conversion module  302 J and/or the Ethernet network interface clock unit  304 J are implemented using optional processor  306  and optional memory  308 . In exemplary embodiments, the optional power supply  310  provides power to the various elements of the Ethernet network interface  202 J. 
       FIGS. 4A-4B  are block diagrams of exemplary embodiments of antenna unit  104 . Each of  FIGS. 4A-4B  illustrates a different embodiment of a remote unit  104 , labeled  104 A- 104 B respectively. 
       FIG. 4A  is a block diagram of an exemplary embodiment of a remote unit  104 , remote unit  104 A, used in distributed antenna systems, such as the exemplary distributed antenna systems  100  described above. The antenna unit  104  includes a distributed antenna system (DAS) transport physical layer processor  402 , a distributed antenna system (DAS) medium access control (MAC) layer processor  404 , a radio access technology (RAT) physical layer processor  406 , a radio frequency (RF) conversion module  408 , optional antenna unit clock unit  410 , optional processor  412 , optional memory  414 , and optional power supply  416 . In exemplary embodiments, the distributed antenna system (DAS) transport physical layer processor  402  is replaced with another type of Layer 1 (L1) processor for a transport Layer 1. In exemplary embodiments, the DAS transport physical layer processor  402  is an Ethernet physical layer processor. In other embodiments, the DAS transport physical layer processor  402  is another type. In exemplary embodiments, the distributed antenna system (DAS) medium access control (MAC) layer processor  404  is replaced with another type of Layer 2 (L2) processor for a transport Layer 2. In exemplary embodiments, the radio access technology (RAT) physical layer processor  406  is replaced with another type of Layer 1 (L1) processor for a radio access technology (RAT) Layer 1. In exemplary embodiments, DAS transport physical layer processor  402 , distributed antenna system medium access control layer processor  404 , RAT physical layer processor  406 , and/or radio frequency conversion module  408  are implemented at least in part by optional processor  412  and memory  414 . In exemplary embodiments, power for the antenna unit is provided by the host unit  102  remotely across a medium and the optional power supply  416  derives and/or extracts power from the medium. In exemplary embodiments, optional power supply  416  is used to power the various components of the antenna unit  104 . 
     In exemplary embodiments, the DAS transport physical layer processor  402  is configured to receive a downlink physical layer data stream from the host unit  102  across the digital communication link  106  and converts the downlink physical layer data stream in the physical layer to downlink distributed antenna system (DAS) transport medium access control (MAC) layer protocol data units (PDU). In exemplary embodiments, the DAS transport physical layer processor  402  is an Ethernet PHY that essentially undoes the processing of the corresponding DAS transport physical layer processor  208  in the host unit  102 . In exemplary embodiments, more input lines are included in the antenna unit  104 A. In exemplary embodiments, the distributed antenna system (DAS) medium access control (MAC) layer processor  404  is configured to convert the downlink distributed antenna system transport medium access control layer protocol data units in the downlink distributed antenna system transport medium access control layer into downlink medium access control layer protocol data units in the medium access control layer. 
     In exemplary embodiments, the RAT physical layer processor  406  is configured to generate a downlink RAT signal from the downlink medium access control layer protocol data units in the medium access control layer. In exemplary embodiments, the RF conversion module  404  converts the baseband downlink RAT signal to radio frequency signals for transmission at antenna  110 . In exemplary embodiments, the RAT physical layer processors  406  are LTE physical layer processors because the signals communicated with the RF conversion module  404  need to be LTE physical layer signals. In these embodiments, the LTE physical layer processors process OFDM in the downlink and SC-FDMA in the uplink. In exemplary embodiments, the LTE physical layer processor (RAT physical layer processor  406 ) in the remote antenna unit  104 A doesn&#39;t perform the upper layer processing (L2/L3) in the protocol stack, rather it only performs the Layer 1 processing up to the creation of the MAC layer data. 
     In exemplary embodiments, some of the RAT physical layer processors  406  are physical layer processors for radio access technologies other than LTE and the physical layer signals received from the corresponding host network interfaces  202  are for these other radio access technologies. In exemplary embodiments, no RAT physical layer processors  406  are included when the RAT physical layer data is transported in some format from the host  102  to the antenna unit  104 A. In exemplary embodiments, combinations of LTE physical layer processors  406 , other RAT physical layer processors  406 , and no RAT physical layer processors  406  are included in antenna unit  104 A. 
     In exemplary embodiments, the RF conversion module  408  receives signals from antenna  110  and converts radio frequency signals to a baseband uplink RAT signal. In exemplary embodiments, the RAT physical layer processor  406  is configured to receive the baseband uplink RAT signal from the RF conversion module  408  and to generate uplink medium access control layer protocol data units in the medium access control layer from the baseband uplink RAT signal. In exemplary embodiments, the distributed antenna system (DAS) medium access control (MAC) layer processor  404  is configured to convert the uplink medium access control layer protocol data units in the medium access control layer into uplink distributed antenna system transport medium access control layer protocol data units in the uplink distributed antenna system transport medium access control layer. In exemplary embodiments, the DAS transport physical layer processor  402  is configured to convert the uplink distributed antenna system transport medium access control layer protocol data units to an uplink physical layer DAS data stream and to communicate the uplink physical layer DAS data stream to the host unit  102  across the digital communication link  106 . 
       FIG. 4B  is a block diagram of an exemplary embodiment of a remote unit  104 , remote unit  104 B, used in distributed antenna systems, such as the exemplary distributed antenna systems  100  described above. The antenna unit  104 B includes an DAS transport physical layer processor  402 , a distributed antenna system (DAS) medium access control (MAC) layer processor  404 , a plurality of radio access technology (RAT) physical layer processors  406  (including RAT physical layer processor  406 - 1 , RAT physical layer processor  406 - 2 , and any quantity of optional RAT physical layer processors  406  through optional RAT physical layer processor  406 -G), a plurality of radio frequency (RF) conversion modules  408 , optional antenna unit clock unit  410 , optional processor  412 , optional memory  414 , and optional power supply  416 . In exemplary embodiments, DAS transport physical layer processor  402 , distributed antenna system medium access control layer processor  404 , RAT physical layer processor  406 , and/or radio frequency conversion module  408  are implemented at least in part by optional processor  412  and memory  414 . In exemplary embodiments, optional power supply  416  is used to power the various components of the antenna unit  104 . Antenna unit  104 B includes similar components to antenna unit  104 A and operates according to similar principles and methods as antenna unit  104 A described above. 
     The differences between antenna unit  104 A and antenna unit  104 B is that antenna unit  104 B includes a plurality of radio access technology (RAT) physical layer processors  406  (such as RAT physical layer processor  406 - 1  through optional RAT physical layer processor  406 -G), a plurality of RF conversion modules  408  (such as RF conversion module  408 - 1  through RF conversion module  408 -C), and optional Ethernet interface  420 . In exemplary embodiments, each of the radio access technology (RAT) physical layer processors  406  is replaced with another type of Layer 1 (L1) processors for a radio access technology (RAT) Layer 1. In exemplary embodiments, the DAS MAC layer processor  404  includes multiplexing functionality enabling multiple different signals to be received and multiplexed in different ways. In exemplary embodiments, such as MIMO applications or multi-signal applications, the DAS MAC layer processor  404  multiplexes the data for the different signals onto the same DAS transport physical layer processor  402  for transport across the digital communication link  106  to the host unit  102 . In exemplary embodiments, the DAS MAC layer processor  404  receives a plurality of uplink data streams from a plurality of RF conversion modules  408 . In exemplary embodiments, the DAS MAC layer processor  404  aggregates at least one uplink data stream received from an RF conversion module  408 - 1  with another uplink data stream received from another RF conversion module  408 - 2 . In exemplary embodiments, the DAS MAC layer processor  404  aggregates a plurality of uplink data streams into an aggregate uplink data stream that is transmitted through the DAS transport physical layer processor  402 . 
     In exemplary embodiments, more than one RAT physical layer processor  406  is communicatively coupled to a single RF conversion module  408 . For example, both optional RAT physical layer processor  406 - 3  and optional RAT physical layer processor  406 - 4  being communicatively coupled to single RF conversion module  408 - 3 . In these embodiments, more than one RAT physical layer data steam is communicated to a single RF conversion module. In exemplary embodiments, the RAT physical layer data stream from a plurality of RAT physical layer processors  406  are in the same band of operation (such as two different two different LTE signals, an LTE signal and a UMTS signal, etc.), such that they can be converted simultaneously by a single RF conversion module  408 . In exemplary embodiments, the two different signals from the two different RAT physical layer data streams are combined digitally at baseband and upconverted simultaneously using RF conversion module  408  using a single power amplifier. 
     In exemplary embodiments, the optional Ethernet interface  408  receives a downlink data stream from the DAS MAC layer processor  404  and converts it to Ethernet packets and communicates the Ethernet packets with an internet protocol network device. The optional Ethernet interface  408  also receives Ethernet packets from the internet protocol network device and converts them to an uplink data stream and communicates it to the DAS MAC layer processor  404 . In exemplary embodiments, the DAS MAC layer processor  404  also multiplexes the uplink data stream from the Ethernet packets with the uplink data streams from the RF conversion modules  408 . The optional Ethernet interface  408  is an example of how the additional bandwidth freed up through the methods described herein can be used to allow for additional services, such as an Ethernet pipe from the host unit  102  to at least one antenna unit  104 . 
     In exemplary embodiments, the optional antenna unit clock unit  410  extracts the master reference clock from the downlink data stream and uses this master clock within the antenna unit  104  to establish a common time base in the antenna unit  104  with the rest of the distributed antenna system  100 . In exemplary embodiments, the optional antenna unit clock unit  410  generates a master reference clock and distributes the generated master reference clock to other components of the distributed antenna system  100  (and even the radio access network interfaces  108 ) in the upstream using the uplink data stream. 
       FIGS. 5A-5C  are block diagrams of exemplary embodiments of RF conversion modules  404  used in antenna units of distributed antenna systems, such as the exemplary antenna unit  100  described above. Each of  FIGS. 5A-5C  are block diagrams of exemplary embodiments of RF conversion module  404 , labeled RF conversion module  404 A- 404 D respectively. 
       FIG. 5A  is a block diagram of an exemplary RF conversion module  404 A including an optional data stream conditioner  502 , an RF frequency converter  504 , an optional RF conditioner  506 , and an RF duplexer  508  coupled to a single antenna  110 . 
     The optional data stream conditioner  502  is communicatively coupled to a RAT physical layer processor  406  and the radio frequency (RF) converter  504 . In the forward path, the optional data stream conditioner  502  conditions the downlink data stream (for example, through amplification, attenuation, and filtering) received from the RAT physical layer processor  406  and passes the downlink data stream to the RF converter  504 . In the reverse path, the optional data stream conditioner  502  conditions the uplink data stream (for example, through amplification, attenuation, and filtering) received from the RF converter  504  and passes the uplink data stream to the RAT physical layer processor  406 . 
     The RF converter  504  is communicatively coupled to the physical layer processor or the optional data stream conditioner  502  on one side and to either RF duplexer  508  or the optional RF conditioner  506  on the other side. In exemplary embodiments, the main function of the RF converter  504  is to convert between digital bits and radio frequency. In exemplary embodiments, the RF converter includes analog to digital converters, digital to analog converters, as well as mixers and local oscillators. In the downstream, the RF converter  504  converts a downlink data stream to downlink radio frequency (RF) signals and passes the downlink RF signals onto either the RF duplexer  508  or the optional RF conditioner  506 . In the upstream, the RF converter  504  converts uplink radio frequency (RF) signals received from either the RF duplexer  508  or the optional RF conditioner  506  to an uplink data stream and passes the uplink data stream to the RAT physical layer processor  406  or the optional data stream conditioner  502 . 
     The RF duplexer  508  is communicatively coupled to either the RF frequency converter  504  or the optional RF conditioner  506  on one side and the antenna  110  on the other side. The RF duplexer  508  duplexes the downlink RF signals with the uplink RF signals for transmission/reception using the antenna  110 . 
       FIG. 5B  is a block diagram of an exemplary RF conversion module  404 B including an optional data stream conditioner  502 , an RF frequency converter  504 , and an optional RF conditioner  506  coupled to a downlink antenna  110 A and an uplink antenna  110 B. RF conversion module  404 B includes similar components to RF conversion module  404 A and operates according to similar principles and methods as RF conversion module  404 A described above. The difference between RF conversion module  404 B and RF conversion module  404 A is that RF conversion module  404 B does not include RF duplexer  508  and instead includes separate downlink antenna  110 A used to transmit RF signals to at least one subscriber unit and uplink antenna  110 B used to receive RF signals from at least one subscriber unit. 
       FIG. 5C  is a block diagram of an exemplary RF conversion module  404 C that communicates downstream and upstream signals using a single antenna  110  through a TDD switch  510  (or other circulator). The RF conversion module  404 D includes an optional data stream conditioner  502 , an RF frequency converter  504 , an optional RF conditioner  506 , and the TDD switch  510  that is communicatively coupled to antenna  110 . RF conversion module  404 C operates according to similar principles and methods as RF conversion module  404 A described above. The difference between RF conversion module  404 C and RF conversion module  404 A is that RF conversion module  404 C uses the TDD switch  510  to switch between a downstream and upstream signal path using a single antenna  110  through TDD switch  510 . The TDD switch switches between the duplexed downlink and uplink signals for RF conversion module  404 C for transmission/reception using the single antenna  110 . 
       FIG. 5D  is a block diagram of an exemplary RF conversion module  404 D- 1  and exemplary RF conversion module  404 D- 2  that share a single antenna  110  through an RF diplexer  512 . The RF conversion module  404 D- 1  includes an optional data stream conditioner  502 - 1 , an RF frequency converter  504 - 1 , an optional RF conditioner  506 - 1 , and an RF duplexer  508 - 1  communicatively coupled to RF diplexer  512  that is communicatively coupled to antenna  110 . Similarly, the RF conversion module  404 D- 2  includes an optional data stream conditioner  502 - 2 , an RF frequency converter  504 - 2 , an optional RF conditioner  506 - 2 , and an RF duplexer  508 - 2  communicatively coupled to RF diplexer  512  that is communicatively coupled to antenna  110 . Each of RF conversion module  404 D- 1  and  404 D- 2  operate according to similar principles and methods as RF conversion module  404 A described above. The difference between RF conversion modules  404 D- 1  and  404 D- 2  and RF conversion module  404 A is that RF conversion modules  404 D- 1  and  404 D- 2  are both coupled to a single antenna  110  through RF diplexer  512 . The RF diplexer  512  diplexes the duplexed downlink and uplink signals for both RF conversion module  404 D- 1  and  404 D- 2  for transmission/reception using the single antenna  110 . 
       FIG. 6  is a block diagram of an exemplary embodiment of a radio access (RAN) network interface  108 , radio access network interface  108 C, used in distributed antenna systems, such as the exemplary distributed antenna systems  100  described above. In exemplary embodiments, exemplary radio access network interface  108 C is a baseband unit (BBU) such as an LTE BBU that has been optimized to more efficiently communicate with remote units  104  in distributed antennas systems  100 . Exemplary radio access network interface  108 C includes at least one core network interface  602  (including core network interface  602 - 1  and any quantity of optional core network interfaces  202  through optional core network interface  602 -B), at least one Layer 2 (L2)/Layer 3 (L3) processor  604  (including L2/L3 processor  604 - 1  and any quantity of optional L2/L3 processors  604  through optional L2/L3 processor  604 -B), a transport medium access control (MAC) layer processor  606  (such as a distributed antenna system (DAS) MAC layer processor), a transport physical layer processor  608  (such as a distributed antenna system (DAS) physical layer processor), an optional radio access network interface clock unit  610 , an optional processor  612 , optional memory  614 , and an optional power supply  616 . In exemplary embodiments, the at least one core network interface  602  is replaced with another type of Layer 1 (L1) and Layer 2 (L2) processor for a core network Layer 1 (L1) and Layer 2 (L2). In exemplary embodiments, the at least one L2/L3 processor  604  is replaced with another type of Layer 2 (L2) and Layer 3 (L3) processor for a radio access technology (RAT) Layer 2 (L2) and Layer 3 (L3). In exemplary embodiments, the at least one L2/L3 processor  604  is an LTE L2/L3 processor. In exemplary embodiments, the transport MAC layer processor  606  is replaced with another type of Layer 2 processor for a transport Layer 2. In exemplary embodiments, the transport physical layer processor  608  is a transport Layer 1 processor for a transport Layer 1. In exemplary embodiments, the transport physical layer processor  608  is an Ethernet physical layer processor. In other embodiments, the transport physical layer processor  608  is another type of physical layer processor for transport through the distributed antenna system. 
     In exemplary embodiments, the core network interfaces  602 , the L2/L3 processors  604 , the transport MAC layer processor  606 , the transport physical layer processor  608  and/or optional radio access network interface clock unit  610  are implemented in whole or in part by optional processor  612  and memory  614 . In exemplary embodiments, power supply  616  provides power for the various components of the radio access network interface  108 C. In exemplary embodiments, the L2/L3 processors  604  are LTE L2/L3 processors because the signals received from the corresponding core network interfaces  602  are LTE core network signals, communicated using Internet Protocol (IP) over Gigabit Ethernet. In exemplary embodiments, some of the L2/L3 processors  604  are L2/L3 processors for radio access technologies (RAT) other than LTE and the signals received from the corresponding core network interfaces  602  are for these other radio access technologies (RAT). In exemplary embodiments, combinations of LTE L2/L3 processors  604  and other radio access technology L2/L3 processors  604  are included in radio access network interface  108 C. In exemplary embodiments, the radio access network interface  108 C provides/distributes power to at least a first of the at least one antenna unit  104 . 
     In the forward path, each core network interface  602  receives downlink physical layer core network signals and converts the downlink physical layer core network signals into downlink L2/L3 core network signals that are communicated to a respective L2/L3 processor  604 . In exemplary embodiments, the purpose of the core network interface  602  is to convert the data from the physical layer format used by the core network  622  into a format acceptable to the RAT L2/L3 processor  604 . In specific implementations, at least one core network interface  602  receives IP core network signals for LTE wireless signals from a core network  622 , converts the IP core network signals into a format compatible with the LTE L2/L3 processor  604 , such as packet data convergence protocol (PDCP) protocol data units (PDUs). In the reverse path, each core network interface  602  receives uplink wireless network information from the L2/L3 processor  604  and converts them into a format for communication with the respective core network  622 . In specific implementations, at least one core network interface  602  receives uplink L2/L3 data signals, such as PDCP PDUs and converts them into uplink physical layer IP core network signals and communicates the core network signals to the at least one additional component in the core network  622 . 
     In the forward path, each L2/L3 processor  604  receives the L2/L3 RAT signals and converts them into downlink radio access technology (RAT) medium access control (MAC) layer protocol data units (PDUs) in the radio access technology (RAT) medium access control (MAC) layer, wherein the radio access technology (RAT) medium access control layer uses relevant bits more efficiently than the radio access technology (RAT) physical layer (such as I/Q modulated LTE samples or other I/Q modulated samples). In the reverse path, each L2/L3 processor  604  receives uplink radio access technology (RAT) medium access control (MAC) layer protocol data units (PDUs) in the radio access technology (RAT) medium access control (MAC) layer and converts the uplink RAT MAC PDUs in the RAT MAC layer into L2/L3 core network signals. 
     In the forward path, the transport MAC layer processor  606  converts the downlink RAT MAC PDUs into downlink transport medium access control (MAC) layer protocol data units (PDUs) in a downlink transport medium access control (MAC) layer for transport to the at least one remote antenna unit  104  (such as through a distributed antenna system (DAS)). In the reverse path, the transport MAC layer processor  606  converts the uplink transport medium access control (MAC) layer protocol data units (PDUs) in an uplink transport medium access control (MAC) layer into the uplink radio access technology (RAT) medium access control (MAC) layer protocol data units (PDUs). In exemplary embodiments, the transport MAC layer processor  606  also broadcasts signals to a plurality of different remote antenna units  104 . In exemplary embodiments, the transport MAC layer processor  606  also combines uplink DAS transport MAC layer PDUs from different antenna units  104  in an intelligent way. 
     In the forward path, the transport physical layer processor  608  converts the downlink transport MAC layer PDUs in the downlink transport MAC layer into downlink transport physical layer data streams in the transport physical layer (such as an Ethernet physical layer or another DAS transport physical layer) and communicates the downlink transport physical layer data streams across the at least one digital communication medium  106  to the at least one antenna unit  104 . In the reverse path, the transport physical layer processor  608  receives uplink transport physical layer data streams in the transport physical layer (such as an Ethernet physical layer or another DAS transport physical layer) from the at least one digital communication medium  106  and converts the uplink transport physical layer data streams into uplink transport MAC layer PDUs in the uplink transport MAC layer. In exemplary embodiments, the transport physical layer processor  608  combines uplink transport physical layer data streams from different antenna units  104  in an intelligent way. 
     In exemplary embodiments, the radio access network interface clock unit  610  generates a master reference clock and distributes the generated master reference clock with the at least one remote antenna unit  104  and/or other components within the distributed antenna system  100 . In exemplary embodiments, the radio access network interface clock unit  610  communicates the master reference clock across a separate clock signal link  620 . In other exemplary embodiments, the radio access network interface clock unit  610  communicates the master reference clock through the transport physical layer processor  608 . In exemplary embodiments, the radio access network interface  108 C receives a master reference clock signal from at least one other component within the distributed antenna system  100 , such as the at least one remote antenna unit  104  or from another external source, such as a source provided from the core network  620 . In exemplary embodiments, the master reference clock is derived from a core network signal received by the at least one core network interface  602 . 
       FIG. 7  is a flow diagram illustrating one exemplary embodiment of a method  700  for efficiently transporting wireless network information through a distributed antenna system. Exemplary method  700  begins at block  702  with converting downlink wireless network information received from a radio access network interface from a first protocol layer to a second protocol layer at a host unit in a distributed antenna system, wherein the second protocol layer uses relevant bits more efficiently than the first protocol layer. Exemplary method  700  proceeds to block  704  with communicating the downlink wireless network information formatted in the second protocol layer from the host unit to at least one antenna unit across at least one digital communication link. Exemplary method  700  proceeds to block  706  with converting the downlink wireless network information communication form the host unit from the second protocol layer to downlink radio frequency signals at the at least one antenna unit. Exemplary method  700  proceeds to block  708  with communicating the downlink radio frequency signals wirelessly using at least one antenna at the at least one antenna unit. 
       FIG. 8  is a flow diagram illustrating one exemplary embodiment of a method  800  for efficiently transporting wireless network information through a distributed antenna system. Exemplary method  800  begins at block  802  with receiving uplink radio frequency signals wirelessly at at least one antenna unit using at least one antenna. Exemplary method  800  proceeds to block  804  with converting uplink radio frequency signals to uplink wireless network information in a second protocol layer at the at least one antenna unit. Exemplary method  800  proceeds to block  806  with communicating the uplink wireless network information formatted in the second protocol layer from the at least one antenna unit to the host unit across at least one digital communication link. Exemplary method  800  proceeds to block  808  with converting the uplink wireless network information received from the at least one antenna unit from the second protocol layer to a first protocol layer, wherein the second protocol layer uses relevant bits more efficiently than the first protocol layer. Exemplary method  800  proceeds to optional block  810  with combining uplink wireless network information received from a plurality of antenna units into aggregate uplink wireless network information. In exemplary embodiments, the uplink wireless network information is combined through summation (either digital or analog), weighted summation, averaging, multiplexing, etc. 
       FIG. 9  is a representation of an exemplary Layer 1 (L1)/Layer 2 (L2) protocol stack  900  for a radio access network (RAN) implementing LTE. The protocol stack  900  includes a packet data convergence protocol (PDCR) layer  902 , a radio link control (RLC) layer  904 , a medium access control (MAC) layer  906 , and a physical (PHY) layer  908 . In exemplary embodiments, each of the packet data convergence protocol (PDCP) layer  902 , the radio link control (RLC) layer  904 , and the medium access control (MAC) layer  906  are replaced with another type of Layer 2 (L2). In exemplary embodiments, the physical (PHY) layer  908  is replaced with another type of Layer 1 (L1). In exemplary embodiments, at the top of the protocol stack  900  into the packet data convergence protocol layer  902  comes IP packets from the radio access network (RAN) of the LTE system. In exemplary embodiments, the IP data then flows down through the radio link control layer  904  to the medium access control layer  906 . In exemplary embodiments, going down through the various layers expands the data rate. In exemplary embodiments, there is only a slight expansion down until the medium access control layer  904 . Once the IP data gets to the physical layer, a much larger expansion of the data rate occurs when going to the LTE physical layer  908 . 
     In exemplary embodiments, the interface between the medium access control layer  904  and the LTE physical layer  908  is a clean interface where processing in layers above are performed by one processing device while processing lasers below are performed by another processing device. In exemplary embodiments, a processor (such as an ARM processor) performs the medium access control (MAC) layer  906  processing and the radio link control (RLC) layer  904  processing. In exemplary embodiments, a digital signal processor (DSP) performs the physical (PHY) layer  908  processing. In other embodiments, a System on a Chip (SoC) performs processing for the medium access control (MAC) layer  906 , the radio link control (RLC) layer  904 , and the physical (PHY) layer  908 . In other exemplary embodiments, a field programmable gate array (FPGA) performs all or part of the processing for the medium access control (MAC) layer  906 , radio link control (RLC) layer  904 , and/or the physical (PHY) layer  908 . In exemplary embodiments, the medium access control (MAC) protocol data units (PDUs) at the medium access control (MAC) layer  906  are transported through the distributed antenna system (such as a distributed antenna system  100 ) instead of I/Q baseband samples (at the LTE physical layer  908 ) because the medium access control (MAC) protocol data units (PDUs) can be more efficiently transported than the I/Q baseband samples. 
       FIGS. 10A-10B  are block diagrams showing interaction in an exemplary system  1000  of various levels of a protocol stack, such as protocol stack  900 . Each of  FIGS. 10A-10B  illustrates a different embodiment of a system  1000 , labeled  1000 A- 1000 B respectively. 
       FIG. 10A  is a block diagram of interaction in an exemplary system  1000 A of various levels of a protocol stack, such as protocol stack  900 . The exemplary system  1000 A includes a radio access network interface  1010 A (such as a baseband unit (BBU) implemented as an eNodeB with an IP Ethernet connection to a core network or other type of baseband unit (BBU)), a host unit  1030 , an antenna unit  1050  connected to the host unit  1030  across a communication link  1040 , and a subscriber unit  1070 . In exemplary embodiments, the radio access network interface  1010 A includes a core network Layer 2 (L2)  1012 , a core network physical (PHY) layer  1014 , a radio access technology (RAT) packet data convergence protocol (PDCP) layer  1016 , a radio access technology (RAT) radio link control (RLC) layer  1018 , a radio access technology (RAT) medium access control (MAC) layer  1020 , and a radio access technology (RAT) physical (PHY) layer  1022 . In exemplary embodiments, the core network Layer 2 (L2)  1012  is an LTE core network Layer 2. In exemplary embodiments, the core network physical (PHY) layer  1014  is replaced with another type of core network Layer 1 (L1). In exemplary embodiments, the core network physical (PHY) layer  1014  is an LTE core network physical layer. In exemplary embodiments, each of the radio access technology (RAT) packet data convergence protocol (PDCP) layer  1016 , the radio access technology (RAT) radio link control (RLC) layer  1018 , and the radio access technology (RAT) medium access control (MAC) layer  1020  are replaced with another type of radio access technology (RAT) Layer 2 (L2). In exemplary embodiments, the radio access technology (RAT) packet data convergence protocol (PDCP) layer  1016  is an LTE packet data convergence protocol (PDCP) layer. In exemplary embodiments, the radio access technology (RAT) radio link control (RLC) layer  1018  is an LTE RLC layer. In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1022  is replaced with another type of radio access technology (RAT) Layer 1 (L1). 
     In exemplary embodiments, the host unit  1030  includes a transport medium access control (MAC) layer  1032 , a radio access technology (RAT) physical (PHY) layer  1034 , and a transport physical (PHY) layer  1036 . In exemplary embodiments the transport medium access control (MAC) layer  1032  is replaced with another type of transport Layer 2 (L2). In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1034  is replaced with another type of radio access technology (RAT) Layer 1 (L1). In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1034  is an LTE physical (PHY) layer. In exemplary embodiments, the transport physical (PHY) layer  1036  is replaced with another type of transport Layer 1 (L1). In exemplary embodiments, the antenna unit  1050  includes a transport medium access control (MAC) layer  1052 , a radio access technology (RAT) physical (PHY) layer  1054 , and a transport physical (PHY) layer  1056 . In exemplary embodiments, the transport medium access control (MAC) layer  1052  is a transport Layer 2 (L2). In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1054  is a radio access technology (RAT) Layer 1 (L1). In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1054  is an LTE physical (PHY) layer. In exemplary embodiments, the transport physical (PHY) layer  1056  is a transport Layer 1 (L1). In exemplary embodiments, the subscriber unit  1070  includes a radio access technology (RAT) packet data convergence protocol (PDCP) layer  1072 , a radio access technology (RAT) radio link control (RLC) layer  1074 , a radio access technology (RAT) medium access control (MAC) layer  1076 , and a radio access technology (RAT) physical (PHY) layer  1078 . In exemplary embodiments, each of the radio access technology (RAT) packet data convergence protocol (PDCP) layer  1072 , the radio access technology (RAT) radio link control (RLC) layer  1074 , and the radio access technology (RAT) medium access control (MAC) layer  1076  is replaced with another type of radio access technology (RAT) Layer 2. In exemplary embodiments, each of the radio access technology (RAT) packet data convergence protocol (PDCP) layer  1072 , the radio access technology (RAT) radio link control (RLC) layer  1074 , and the radio access technology (RAT) medium access control (MAC) layer  1076  are LTE Layer 2 protocol layers. In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1078  is replaced with another type of radio access technology (RAT) Layer 1. In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1078  is an LTE Layer 1 protocol layer. 
     In exemplary embodiments, the RAT physical (PHY) layer  1034  of the host unit  1030  is communicatively coupled to the RAT physical (PHY) layer  1022  of the radio access network interface  1010 A. In exemplary embodiments, the transport physical (PHY) layer  1056  of the antenna unit  1050  is communicatively coupled to the transport physical (PHY) layer  1036  of the host unit  1030  by the communication link  1040 . In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1054  of the antenna unit  1050  is coupled to an antenna  1060 . In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1078  of the subscriber unit is communicatively coupled to an antenna  1080 . In exemplary embodiments, the RAT physical (PHY) layer  1054  communicates with the RAT physical (PHY) layer  1078  across a wireless link between antenna  1060  and antenna  1080 . 
     In exemplary embodiments, the core network physical (PHY) layer  1014  receives core network physical (PHY) layer protocol data units (PDUs) (such as a serial data stream) from a component in a core network (such as core network  622  described above with reference to  FIG. 6 ) and converts the core network physical layer PDUs into core network Layer 2 (L2) protocol data units (PDUs). In exemplary embodiments, the core network Layer 2 (L2)  1012  converts the core network L2 PDUs into Layer 3 (L3) protocol data units (PDUs) that are passed to the radio access technology (RAT) packet data convergence protocol (PDCP) layer  1016 . In exemplary embodiments, the L3 PDUs are Internet Protocol (IP) PDUs. In exemplary embodiments, the RAT PDCP layer  1016  converts the L3 PDUs to radio access technology (RAT) L2 PDUs that are further processed by the RAT radio link control (RLC) layer  1018  and the RAT medium access control (MAC) layer  1020 . The RAT physical (PHY) layer  1022  converts the RAT L2 PDUs (such as RAT MAC PDUs) into radio access technology (RAT) physical layer data and communicates the RAT physical layer data (which is LTE physical layer data in some embodiments, such as I/Q data) to the RAT physical (PHY) layer  1034  of the host unit  1030 . 
     In exemplary embodiments, the host unit  1030  receives radio access technology (RAT) physical layer data (such as LTE physical layer data) at the RAT physical (PHY) layer  1034  from the RAT physical (PHY) layer  1022  of the radio access network interface  1010 A. In exemplary embodiments, the RAT physical layer data is analog RF or CPRI baseband data. In exemplary embodiments, this RAT physical layer data is the data that will be transmitted over the air interface between antennas  1060  and antennas  1080 . In exemplary embodiments, the host unit  1030  receives the physical layer data from the RAT physical (PHY) layer  1034  through either a digital interface or an analog RF interface. In exemplary embodiments, the RAT physical (PHY) layer  1034  of the host unit  1030  undoes the RAT physical layer processing performed by the radio access network interface  1010 A and extracts just the radio access technology (RAT) medium access control (MAC) protocol data units (PDUs) in the RAT MAC layer and passes the RAT MAC PDUs (such as LTE MAC PDUs) to the RAT medium access control (MAC) layer  1032 . In exemplary embodiments, the RAT MAC PDUs are translated into transport medium access control (MAC) layer protocol data units (PDUs) by the transport medium access control (MAC) layer  1032 , such as DAS MAC PDUs. These transport MAC PDUs are sent over the communication link  1040  by the transport physical (PHY) layer  1036  (such as an Ethernet PHY or other DAS physical (PHY) processor) as synchronous serial data streams. In exemplary embodiments, packet data may be used for transport across the communication link  1040 . In exemplary embodiments, synchronization bits, timing bits, etc. are inserted by the transport physical (PHY) layer  1036  creating additional overhead. In exemplary embodiments, the communication link  1040  is a Category building cable (or some other lower bandwidth cable). 
     In exemplary embodiments, the serial stream of data is received at the transport physical (PHY) layer  1056  from the communication link  1040 . In exemplary embodiments, the transport physical (PHY) layer  1056  is an Ethernet PHY or some other DAS physical (PHY) layer. In exemplary embodiments, the transport physical (PHY) layer of the antenna unit  1050  extracts the transport medium access control (MAC) PDUs in the transport medium access control (MAC) layer  1052 , such as DAS transport MAC PDUs. The transport medium access control (MAC) layer  1052  synchronizes to the stream of received transport MAC PDUs and reframes the transport MAC PDUs into the radio access technology (RAT) medium access control (MAC) protocol data units (PDUs) in the radio access technology (RAT) medium access control (MAC) layer. These RAT MAC PDUs are run through the RAT physical (PHY) layer  1054  resulting in a signal that is formatted in the same way as the radio access technology (RAT) physical layer data (such as LTE physical layer data) output from the RAT physical (PHY) layer  1022  of the radio access network interface  1010 A. In exemplary embodiments, the RAT physical layer data is output via the RAT physical (PHY) layer  1054  and the antenna  1060  across the wireless link to the antenna  1080  of the physical (PHY) layer  1078  of the subscriber unit  1070 . By transporting across the communication link  1040  using the transport MAC PDUs through the transport physical (PHY), the data rate of the signals over the communication link  1040  is reduced. 
     In the uplink the antenna unit  1050  receives signals at the RAT physical (PHY) layer  1054  via the antenna  1060  from the subscriber unit  1070 , just as the radio access network interface  1010 A could. The RAT physical (PHY) layer  1054  of the antenna unit  1050  processes these uplink signals into uplink RAT MAC PDUs in the RAT MAC layer. The RAT MAC PDUs are translated into the transport MAC PDUs by the transport MAC layer  1052 . The transport MAC PDUs are converted by the transport physical (PHY) layer  1056  and sent over the communication link  1040  to the transport physical (PHY) layer  1036  of the host unit  1030 . In the host unit  1030 , the detected transport data streams are gathered from the antenna units  104  by the transport physical (PHY) layer  1036  (instead of I/Q RAT samples) and are converted to uplink transport MAC PDUs by the transport physical (PHY) layer  1036 . The uplink transport MAC PDUs are translated into uplink RAT MAC PDUs by the transport MAC layer  1032 . 
     In exemplary embodiments, the uplink data from the antenna units  1050  is combined in the host unit  1030 . In exemplary embodiments, the uplink transport MAC PDUs received from antenna units  1050  are intelligently combined using majority logic, soft weighted combining, averaging or other combining methods by the transport MAC layer  1032 . The combined MAC PDU is then translated into uplink RAT MAC PDUs by the transport MAC layer  1032 . In exemplary embodiments, the uplink combining is performed in the transport physical layer  1036 . In exemplary embodiments, the uplink combining is performed on the RAT MAC PDUs in the transport MAC layer  1032 . The uplink RAT MAC PDUs are communicated as RAT physical layer data by the RAT PHY layer  1034  to the RAT physical (PHY) layer  1022  of the radio access network interface  1010 A by the RAT physical (PHY) layer  1034  of the antenna unit  1050 . In exemplary embodiments, the RAT PHY layer  1022  of the radio access network interface  1010 A converts the RAT physical layer data into uplink RAT MAC PDUs that are passed to the RAT MAC layer  1020  and up through RAT RLC layer  1018  and RAT PDCP layer  1016  and converted into L3 PDUs that are communicated to the core network Layer 2 (L2)  1012  down the core network stack and converted into core network physical data and communicated by the core network physical layer  1014  to the upstream core network component. 
       FIG. 10B  is a block diagram of interaction in an exemplary system  1000 B of various levels of a protocol stack, such as protocol stack  900 . The exemplary system  1000 B includes a radio access network interface  1010 B (such as a baseband unit (BBU) implemented as an eNodeB with an IP Ethernet connection to a core network or other type of baseband unit (BBU)), an antenna unit  1050  connected to the radio access network interface  1010 B across a communication link  1040 , and a subscriber unit  1070 . In exemplary embodiments, the radio access network interface  1010 B includes a core network Layer 2 (L2)  1012 , a core network physical (PHY) layer  1014 , a radio access technology (RAT) packet data convergence protocol (PDCP) layer  1016 , a radio access technology (RAT) radio link control (RLC) layer  1018 , a radio access technology (RAT) medium access control (MAC) layer  1020 , a transport medium access control (MAC) layer  1102 , and a transport physical (PHY) layer  1104 . In exemplary embodiments, the core network Layer 2 (L2)  1012  is an LTE core network Layer 2 (L2). In exemplary embodiments, the core network physical (PHY) layer  1014  is replaced with another type of core network Layer 1 (L1). In exemplary embodiments, the core network physical layer  1012  is an LTE core network physical layer. In exemplary embodiments, each of the radio access technology (RAT) packet data convergence protocol (PDCP) layer  1016 , the radio access technology (RAT) radio link control (RLC) layer  1018 , and the radio access technology (RAT) medium access control (MAC) layer  1020  is replaced with another type of radio access technology (RAT) Layer 2 (L2). In exemplary embodiments, the radio access technology (RAT) packet data convergence protocol (PDCP) layer  1016  is an LTE packet data convergence protocol (PDCP) layer. In exemplary embodiments, the radio access technology (RAT) radio link control (RLC) layer  1018  is an LTE radio link control (RLC) layer. In exemplary embodiments, the radio access technology (RAT) medium access control (MAC) layer  1020  is an LTE medium access control (MAC) layer. In exemplary embodiments, the transport medium access control (MAC)  1102  is replaced with another type of transport Layer 2 (L2). In exemplary embodiments, the transport physical (PHY) layer  1104  is replaced with another type of transport Layer 1 (L1). 
     In exemplary embodiments, the antenna unit  1050  includes a transport medium access control (MAC) layer  1052 , a radio access technology (RAT) physical (PHY) layer  1054 , and a transport physical (PHY) layer  1056 . In exemplary embodiments, the transport medium access control (MAC) layer  1052  is replaced with another type of transport Layer 2 (L2). In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1054  is replaced with another type of radio access technology (RAT) Layer 1 (L1). In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1054  is an LTE physical (PHY) layer. In exemplary embodiments, the transport physical (PHY) layer  1056  is replaced with another type of transport Layer 1 (L1). In exemplary embodiments, the subscriber unit  1070  includes a radio access technology (RAT) packet data convergence protocol (PDCP) layer  1072 , a radio access technology (RAT) radio link control (RLC) layer  1074 , a radio access technology (RAT) medium access control (MAC) layer  1076 , and a radio access technology (RAT) physical (PHY) layer  1078 . In exemplary embodiments, each of the radio access technology (RAT) packet data convergence protocol (PDCP) layer  1072 , the radio access technology (RAT) radio link control (RLC) layer  1074 , and the radio access technology (RAT) medium access control (MAC) layer  1076  is replaced with another type of radio access technology (RAT) Layer 2. In exemplary embodiments, each of the radio access technology (RAT) packet data convergence protocol (PDCP) layer  1072 , the radio access technology (RAT) radio link control (RLC) layer  1074 , and the radio access technology (RAT) medium access control (MAC) layer  1076  are LTE Layer 2 protocol layers. In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1078  is replaced with another type of radio access technology (RAT) Layer 1. In exemplary embodiments, the radio access technology (RAT) physical (PHY) layer  1078  is an LTE Layer 1 protocol layer. 
     Distributed antenna system  1000 B includes similar components to distributed antenna system  1000 A and operates according to similar principles and methods as distributed antenna system  1000 A described above. The difference between distributed antenna system  1000 B and distributed antenna system  1000 A is that distributed antenna system  1000 B does not include the host unit  1030  and the radio access network interface  1010 B includes transport medium access control (MAC) layer  1102  in addition to RAT medium access control (MAC) layer  1020  and transport physical (PHY) layer  1104  instead of RAT physical (PHY) layer  1022 . The transport medium access control (MAC) layer  1102  and transport physical (PHY) layer  1104  enables the radio access network interface  1010 B to communicate directly with antenna unit  1050  using the transport MAC PDUs. 
     In exemplary embodiments in the downlink, the core network Layer (L2)  1012 , the core network physical layer  1014 , the RAT PDCP layer  1016 , the RAT RLC layer  1018 , and the RAT medium access control (MAC) layer  1020  function as described above with reference to the radio access network interface  1010 A of  FIG. 10A . The difference in the radio access network interface  1010 B being that the transport medium access control (MAC) layer  1102  converts from radio access technology (RAT) medium access control (MAC) PDUs to transport medium access control (MAC) PDUs. In exemplary embodiments, the transport physical (PHY) layer  1104  is implemented using Ethernet PHY devices through which the transport medium access control (MAC) PDUs are communicated across the communication link  1040 . These transport MAC PDUs are sent over the communication link  1040  by the transport physical (PHY) layer  1104  (such as an Ethernet PHY or other DAS physical (PHY) layer) as synchronous serial data streams. In exemplary embodiments, packet data may be used for transport across the communication link  1040 . In exemplary embodiments, synchronization bits, timing bits, etc. are inserted by the transport physical (PHY) layer  1036  creating additional overhead. In exemplary embodiments, the communication link  1040  is a Category building cable (or some other lower bandwidth cable). 
     In exemplary embodiments, the serial stream of data is received at the transport physical (PHY) layer  1058  from the communication link  1040 . In exemplary embodiments, the transport physical (PHY) layer  1058  is implemented using Ethernet PHY devices or some other DAS physical (PHY) layer. In exemplary embodiments, the transport physical (PHY) layer of the antenna unit  1050  extracts the transport medium access control (MAC) PDUs in the transport medium access control (MAC) layer  1054 , such as DAS transport MAC PDUs. The transport medium access control (MAC) layer  1054  synchronizes to the stream of received transport MAC PDUs and reframes the transport MAC PDUs into the radio access technology (RAT) medium access control (MAC) protocol data units (PDUs) in the radio access technology (RAT) medium access control (MAC) layer. These RAT MAC PDUs are run through the RAT physical (PHY) layer  1056  resulting in a signal that is formatted in the same way as the radio access technology (RAT) physical layer data (such as LTE physical layer data) output from the RAT physical (PHY) layer  1022  of the radio access network interface  1010 A. In exemplary embodiments, the RAT physical layer data is output via the RAT physical (PHY) layer  1056  and the antenna  1060  across the wireless link to the antenna  1080  of the physical (PHY) layer  1078  of the subscriber unit  1070 . By transporting across the communication link  1040  using the transport MAC PDUs through the transport physical (PHY) layer, the data rate of the signals transported over the communication link  1040  is reduced. 
     In the uplink the antenna unit  1050  receives signals at the RAT physical (PHY) layer  1056  via the antenna  1060  from the subscriber unit  1070 , just as the radio access network interface  1010 A could. The RAT physical (PHY) layer  1056  of the antenna unit  1050  processes these uplink signals into uplink RAT MAC PDUs in the RAT MAC layer. The RAT MAC PDUs are translated into the transport MAC PDUs by the transport MAC layer  1054 . The transport MAC PDUs are converted by the transport physical (PHY) layer  1058  and sent over the communication link  1040  to the transport physical (PHY)  1104  of the radio access network interface  1010 B. In the radio access network interface  1010 B, the detected transport data streams are gathered from the antenna units  1050  by the transport physical (PHY)  1104  (instead of I/Q RAT samples) and are converted to uplink transport MAC PDUs by the transport physical (PHY) layer  1104 . The uplink transport MAC PDUs are translated into uplink RAT MAC PDUs by the transport MAC layer  1102  and communicated to the RAT medium access control (MAC)  1020  of the radio access network interface  1010 B. In the radio access network interface  1010 B, the information is communicated up the RAT/transport side of the protocol stack in the radio access network interface  1010 B and down the core network side of the protocol stack  1010 B as described above with reference to radio access network interface  1010 A. 
     In exemplary embodiments, the uplink data from the antenna units  1050  is combined in the radio access network interface  1010 B. In exemplary embodiments the uplink transport MAC PDUs received from antenna units  1050  are intelligently combined using majority logic, soft weighted combining, averaging or other combining methods by the transport MAC layer  1102 . The combined MAC PDU is then translated into uplink RAT MAC PDUs by the transport MAC layer  1102 . In exemplary embodiments the uplink combining is performed in the transport physical layer  1104 . In exemplary embodiments the uplink combining is performed on the RAT MAC PDUs in the transport MAC layer  1102 . 
     In exemplary embodiments, any of the processors described above may include or function with software programs, firmware or other computer readable instructions for carrying out various methods, process tasks, calculations, and control functions, used in the digital processing functionality described herein. These instructions are typically stored on any appropriate computer readable medium used for storage of computer readable instructions or data structures. The computer readable medium can be implemented as any available media that can be accessed by a general purpose processor (GPP) or special purpose computer or processor (such as a field-programmable gate array (FPGA), application-specific integrated circuit (ASIC) or other integrated circuit), or any programmable logic device. Suitable processor-readable media may include storage or memory media such as magnetic or optical media. For example, storage or memory media may include conventional hard disks, Compact Disk—Read Only Memory (CD-ROM), volatile or non-volatile media such as Random Access Memory (RAM) (including, but not limited to, Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate (DDR) RAM, RAIVIBUS Dynamic RAM (RDRAM), Static RAM (SRAM), etc.), Read Only Memory (ROM), Electrically Erasable Programmable ROM (EEPROM), and flash memory, etc. Suitable processor-readable media may also include transmission media such as electrical, electromagnetic, or digital signals, conveyed via a communication medium such as a network and/or a wireless link. 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiments shown. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof. 
     Example Embodiments 
     Example 1 includes an antenna unit comprising: a transport Layer 1 processor configured to receive a downlink transport Layer 1 data stream from an upstream device and to convert the downlink transport Layer 1 data stream into downlink transport Layer 2 protocol data units in a downlink transport Layer 2; a Layer 2 processor configured to convert the downlink transport Layer 2 protocol data units in the downlink transport Layer 2 into downlink radio access technology Layer 2 protocol data units in a radio access technology Layer 2; a radio access technology Layer 1 processor configured to generate a downlink radio access technology Layer 1 signal from the downlink radio access technology Layer 2 protocol data units in the radio access technology Layer 2; and a radio frequency conversion module configured to convert the downlink radio access technology Layer 1 signal into radio frequency signals for communication using an antenna. 
     Example 2 includes the antenna unit of Example 1, wherein the upstream device is at least one of a radio access network interface and a baseband unit. 
     Example 3 includes the antenna unit of any of Examples 1-2, wherein the upstream device is a host unit in a distributed antenna system. 
     Example 4 includes the antenna unit of any of Examples 1-3, wherein the antenna is at least one of coupled to the antenna unit and integrated into the antenna unit. 
     Example 5 includes the antenna unit of any of Examples 1-4, wherein the Layer 2 processor is a medium access control layer processor; and wherein the transport Layer 1 processor is a physical layer processor. 
     Example 6 includes the antenna unit of any of Examples 1-5, wherein the radio access technology Layer 1 is a Long Term Evolution physical layer; and wherein the radio access technology Layer 2 is a Long Term Evolution medium access control layer. 
     Example 7 includes an antenna unit comprising: a radio frequency conversion module configured to convert radio frequency signals received using an antenna into a Layer 1 uplink radio access technology signal; a radio access technology Layer 1 processor configured to generate uplink radio access technology Layer 2 protocol data units in a radio access technology Layer 2 from the Layer 1 uplink radio access technology signal; a Layer 2 processor configured to convert the uplink radio access technology Layer 2 protocol data units in a radio access technology Layer 2 into uplink transport Layer 2 protocol data units in the uplink transport Layer 2; and a transport Layer 1 processor configured to convert uplink transport Layer 2 protocol data units in an uplink transport Layer 2 into an uplink transport Layer 1 data stream and to communicate the uplink transport Layer 1 data stream to an upstream device. 
     Example 8 includes the antenna unit of Example 7, wherein the upstream device is at least one of a radio access network interface and a baseband unit. 
     Example 9 includes the antenna unit of any of Examples 7-8, wherein the upstream device is a host unit in a distributed antenna system. 
     Example 10 includes the antenna unit of any of Examples 7-9, wherein the antenna is at least one of coupled to the remote antenna unit and integrated into the remote antenna unit. 
     Example 11 includes the antenna unit of any of Examples 7-10, wherein the Layer 2 processor is a medium access control layer processor; and wherein the transport Layer 1 processor is a physical layer processor. 
     Example 12 includes the antenna unit of any of Examples 7-11, wherein the radio access technology Layer 1 is a Long Term Evolution physical layer; and wherein the radio access technology Layer 2 is a Long Term Evolution medium access control layer. 
     Example 13 includes a system comprising: a radio access network interface; at least one remote antenna unit communicatively coupled to the radio access network interface across a first communication link; wherein the radio access network interface is configured to communicate a downlink transport Layer 1 data stream to the at least one remote antenna unit across the first communication link; wherein the at least one remote antenna unit is configured to: receive the downlink transport Layer 1 data stream from the radio access network interface; convert the downlink transport Layer 1 data stream into downlink transport Layer 2 protocol data units in a downlink transport Layer 2; convert the downlink transport Layer 2 protocol data units in the downlink transport Layer 2 into downlink radio access technology Layer 2 protocol data units in a radio access technology Layer 2; generate a downlink radio access technology Layer 1 signal from the downlink radio access technology Layer 2 protocol data units in the radio access technology Layer 2; and convert the downlink radio access technology Layer 1 signal into radio frequency signals for communication using an antenna. 
     Example 14 includes the system of Example 13, wherein the antenna is at least one of coupled to the at least one remote antenna unit and integrated into the at least one remote antenna unit. 
     Example 15 includes the system of any of Examples 13-14, wherein at least a first digital communication link of the at least one digital communication link is transported across a medium that is a Category building cabling. 
     Example 16 includes the system of any of Examples 13-15, wherein the digital communication link is implemented using Ethernet physical layer devices. 
     Example 17 includes the system of any of Examples 13-16, further comprising: a host unit communicatively coupled between the radio access network interface and the at least one antenna unit, the host unit configured to route the downlink wireless network information from the radio access network interface to the at least one remote antenna unit. 
     Example 18 includes a system comprising: a radio access network interface; at least one remote antenna unit communicatively coupled to the radio access network interface across a first communication link; wherein the radio access network interface is configured to receive an uplink transport Layer 1 data stream from the at least one remote antenna unit across the first communication link; wherein the at least one remote antenna unit is configured to: convert radio frequency signals received using an antenna into a Layer 1 uplink radio access technology signal; generate uplink radio access technology Layer 2 protocol data units in a radio access technology Layer 2 from the Layer 1 uplink radio access technology signal; convert the uplink radio access technology Layer 2 protocol data units in the radio access technology Layer 2 into uplink transport Layer 2 protocol data units in the uplink transport Layer 2; convert the uplink transport Layer 2 protocol data units in the uplink transport Layer 2 into an uplink transport Layer 1 data stream; communicate the uplink transport Layer 1 data stream to the radio access network interface. 
     Example 19 includes the system of Example 18, wherein the antenna is at least one of coupled to the at least one remote antenna unit and integrated into the at least one remote antenna unit. 
     Example 20 includes the system of any of Examples 18-19, wherein at least a first digital communication link of the at least one digital communication link is transported across a medium that is a Category building cabling. 
     Example 21 includes the system of any of Examples 18-20, wherein the digital communication link is implemented using Ethernet physical layer devices. 
     Example 22 includes the system of any of Examples 18-21, wherein the radio access network interface is further configured to combine multiple uplink wireless network information received from a plurality of remote antenna units including the at least one remote antenna unit. 
     Example 23 includes the system of any of Examples 18-22, further comprising: a host unit communicatively coupled between the radio access network interface and the at least one antenna unit, the host unit configured to combine multiple uplink wireless network information received from a plurality of remote antenna units including the at least one remote antenna unit. 
     Example 24 includes the system of Example 23, wherein the host unit is configured to combine the multiple uplink wireless network information received from the plurality of antenna units using at least one of majority logic and weighted combining. 
     Example 25 includes the system of any of Examples 23-24, wherein the host unit is configured to combine the multiple uplink wireless network information received from the plurality of antenna units based on quality metrics received from the plurality of antenna units. 
     Example 26 includes a method for efficiently transporting wireless network information though a system, comprising: receiving a downlink transport Layer 1 data stream from an upstream device at a remote antenna unit; converting the downlink transport Layer 1 data stream into downlink transport Layer 2 protocol data units in a downlink transport Layer 2 at the remote antenna unit; converting the downlink transport Layer 2 protocol data units in the downlink transport Layer 2 into downlink radio access technology Layer 2 protocol data units in a radio access technology Layer 2 at the remote antenna unit; generating a downlink radio access technology Layer 1 signal from the downlink radio access technology Layer 2 protocol data units in the radio access technology Layer 2 at the remote antenna unit; and converting the downlink radio access technology Layer 1 signal into radio frequency signals for communication using an antenna at the remote antenna unit. 
     Example 27 includes the method of Example 26, further comprising: wherein the upstream device is at least one of a radio access network interface and a baseband unit; and communicating the downlink transport Layer 1 data stream to the remote antenna unit from the at least one of the radio access network interface and the baseband unit. 
     Example 28 includes the method of any of Examples 26-27, wherein receiving a downlink transport Layer 1 data stream from the upstream device at the remote antenna unit occurs using Ethernet physical layer devices. 
     Example 29 includes a method for efficiently transporting wireless network information through a system, comprising: converting radio frequency signals received using an antenna at a remote antenna unit into a uplink radio access technology Layer 1 signal at the remote antenna unit; generating uplink radio access technology Layer 2 protocol data units in a radio access technology Layer 2 from the uplink radio access technology Layer 1 signal at the remote antenna unit; converting the uplink radio access technology Layer 2 protocol data units in the radio access technology Layer 2 into uplink transport Layer 2 protocol data units in an uplink transport Layer 2 at the remote antenna unit; converting the uplink transport Layer 2 protocol data units in the uplink transport Layer 2 into an uplink transport Layer 1 data stream at the remote antenna unit; and communicating the uplink transport Layer 1 data stream to an upstream device at the remote antenna unit. 
     Example 30 includes the method of Example 29, further comprising: wherein the upstream device is at least one of a radio access network interface and a baseband unit; and communicating the uplink transport Layer 1 data stream from the remote antenna unit to the at least one of the radio access network interface and the baseband unit. 
     Example 31 includes the method of any of Examples 29-30, wherein communicating the uplink transport Layer 1 data stream to the upstream device from the remote antenna unit occurs using Ethernet physical layer devices.