Patent ID: 12192124

DETAILED DESCRIPTION

Channel Aggregation Introduction

Channel aggregation is described for wireless communication in which exemplary embodiments provide that two or more communication channels can be channel-aggregated as communication channels, including for a single service. As described herein, channel aggregation may include transmitting and receiving data at a wireless communication device on different communication channels in which data from a single service may be assigned for communication on any one of two or more aggregated communication channels as determined by a channel aggregation system. The channel-aggregated communication channels are each individually properly formed communication channels. The channel-aggregated communication channels can be adjacent channels in the same frequency band or non-adjacent channels in the same or different frequency bands.

In an exemplary embodiment, a base station operable for channel-aggregated communication includes a scheduling module that (i) generates a first data set for communication via a first communication channel and (ii) generates a second data set for communication via a second communication channel, where the first data set and the second data set each include data intended for transmission to a particular subscriber station. The base station can also include a first radio to transmit the first data set to the subscriber station via the first communication channel and a second radio to transmit the second data set to the subscriber station via the second communication channel.

In another exemplary embodiment, a subscriber station operable for channel-aggregated communication includes a first radio to receive a first data set via a first communication channel, and it includes a second radio to receive a second data set via a second communication channel. The subscriber station can also include a receiving unit with a channel aggregation module that is capable of handling channel-aggregated communications. The channel aggregation module is to formulate an integrated data set for a single service from the first data set and the second data set.

In one particular example, two different communication channels can be a licensed communication channel and a non-exclusively-licensed communication channel. For example, a base station or base station system can be operable for channel-aggregated communication and implemented in a wireless communication system to transceive data via non-adjacent, channel-aggregated communication channels that include a licensed communication channel and a non-exclusively-licensed communication channel. Similarly, subscriber stations can each be operable for channel-aggregated communication and implemented in such a wireless communication system so as to transceive data via the licensed and the non-exclusively-licensed channel-aggregated communication channels.

Although features and concepts of the described systems, methods, devices, media, etc. for channel aggregation can be implemented in any number of different environments, communications systems, processing-based systems, structures, and/or other configurations, exemplary embodiments of channel aggregation are described in the context of the following example systems and environments.

Channel Aggregation Exemplary Embodiments

FIG.1is a block diagram of an example wireless environment100having multiple wireless devices102and104and multiple communication links106, each of which may include first and second (or more) channels110. As illustrated, wireless environment100includes a base station102, one or more networks108, “n” subscriber stations104, and “m” communication links106, with “n” and “m” being the same or different integers. Although a single respective communication link106is shown as being associated with each respective subscriber station104, each subscriber station104may be simultaneously participating in multiple communication links106. By way of example only, a respective first and second communication link106may correspond to a respective WiMAX and WiFi communication.

Wireless communications environment100is representative generally of many different types of wireless communications environments, including but not limited to those pertaining to wireless local area networks (wireless LANs) (e.g., Wi-Fi or WiMAX technology); wireless wide area networks (wireless WANs) (e.g., WiMAX technology); ad hoc wireless networks (e.g., Wi-Fi or Bluetooth technology); cellular technology (including so-called personal communication services (PCS)); trunking technology; metropolitan area networks (MANs), including hybrid or multi-use (e.g., WiMAX) technology; some combination thereof; and so forth.

In wireless communications environment100, base station102is in wireless communication with subscriber stations104(1),104(2) . . .104(n) via wireless communications or communication links106(1),106(2) . . .106(m), respectively. Although implementations may vary, base station102is typically fixed, and subscriber stations104are usually mobile, nomadic, or stationary. Although wireless communications environment100depicts base station102as communicating with “n” subscriber stations104in one general direction, base station102may actually be communicating with any number of subscriber stations104in any number of directions, including in different sectors or omni-directionally.

As illustrated, base station102is capable of accessing network(s)108. Network(s)108may be one or more of a wired network, another wireless network, a combination thereof, and so forth. Access to network108enables base station102to forward data from subscriber stations104to external network locations and vice versa. Network(s)108may also be used for backhaul purposes. Examples of network108include, by way of example but not imitation, the internet, a landline telephone network, another wireless network, wired nodes of the overall network of base station102, LANs/WANs/MANs, some combination thereof, etc. that are operating in accordance with any given communication standard or standards.

Base station102may be, for example, a nexus point, a trunking radio, a switch or router, an access point, a traditional cellular base transceiver station, some combination and/or derivative thereof, and so forth. Subscriber stations104may be, for example, a hand-held device; a server, client, personal, desktop, and/or laptop computer; a wireless expansion card, module, adapter, or similar apparatus that is coupled to a computer or other device; a storage device; a set-top box or other television-related device; a personal digital assistant (PDA); a mobile phone or other mobile appliance; a vehicle having a wireless communication device; a tablet or hand/palm-sized computer; a wireless router; a node of a wireless mesh network; a portable inventory-related scanning device; any device capable of processing generally; some combination thereof; and so forth.

Base station102may interact with subscriber stations104in accordance with any individual or combined standardized and/or specialized air interface technologies. Example air interface technologies include, by way of example but not limitation, an IEEE 802.11 standard, an IEEE 802.16 standard, a draft IEEE 802.22 standard, various cellular phone standards, some combination or derivative thereof, or any other such technology. Applicable wireless schemes include, by way of example but not limitation, orthogonal frequency division multiple access (OFDMA) schemes, including both time division duplexing (TDD) and frequency division duplexing (FDD); orthogonal frequency division multiplexing (OFDM) schemes, including both TDD and FDD; time division-code division multiple access (TD-CDMA) schemes; general frequency division duplexing (FDD) schemes; single carrier (SC) schemes; time division multiplexing (TDM) schemes; some combination thereof; and so forth. Moreover, such schemes can include those requiring line of sight (LOS) communications as well as those allowing non-line of sight (NLOS) communications.

For an exemplary embodiment of channel aggregation, each wireless communication link106may be comprised of two or more aggregated (communication) channels110. As illustrated in particular for wireless link106(m), a single service112is being communicated using multiple aggregated channels110. More specifically, a first channel110(1) and a second channel110(2) are channel-aggregated for communications via wireless link106(m) for single service112. Although only two channels110(1) and110(2) and a single service112are explicitly illustrated, channel aggregation may be implemented using any number of two or more communication channels and may involve more than one service. In an example embodiment, integrated data is divided into first data and second data. The first data is transmitted on a first channel. The second data is simultaneously transmitted on a second channel such that the first data and the second data are transmitted in a coordinated manner by aggregating the first channel and the second channel.

First and second aggregated channels110(1) and110(2) may each be any type of channel. They may also share none, one, many, or even all channel type characteristics. Example channel type characteristics include licensing, adjacency, frequency band, air interface technology, wireless scheme, transmit power, combination(s) thereof, and so forth. Thus, by way of example only, aggregated communication channels may be: licensed or non-exclusively-licensed channels, adjacent or non-adjacent channels, channels within different frequency bands or channels within the same frequency band, channels with the same or different wireless schemes, and so forth.

For a channel aggregation including a first communication channel110(1) and a second communication channel110(2), many combinations of different channel type characteristics may be implemented. By way of example only, the two aggregated channels110(1) and110(2) may be: [i] a licensed channel and a non-exclusively-licensed channel, [ii] two licensed channels in the same band, [iii] two licensed channels in different bands, [iv] two non-exclusively-licensed channels in the same band, [v] two non-exclusively-licensed channels in different bands, and so forth. If the two channels are within the same band, they may be adjacent or non-adjacent.

Phrased differently, two channel-aggregated communication channels110may be, by way of example only, one of the following seven [7] combinations: [1 and 2] adjacent, same band (either licensed (L) or non-exclusively-licensed (NEL), but not both); [3 and 4] non-adjacent, same band (either L or NEL, but not both); and [5, 6, and 7] non-adjacent, different bands (L and NEL, L and L, or NEL and NEL). Non-exclusively-licensed channels and bands include those that do not require an exclusive license for operation. Examples of non-exclusively-licensed channels and bands include, but are not limited to, those that are lightly-licensed, those that are licensed-exempt, and so forth.

Additionally, channel-aggregated communication channels can be made to appear as independent, properly formed channels such that so-called legacy devices can operate using any single communication channel as if communicating with a base station using a communication channel that is not channel-aggregated. Such legacy devices are not configured to understand and/or implement channel aggregation. However, if each channel-aggregated communication channel is independent and properly-formed, the legacy device can not only communicate with the base station that is implementing channel aggregation, but the legacy device may also actually communicate with the base station using any one of the aggregated channels. For example, a first channel and a second channel may be properly formed when a subscriber station that is unable to implement channel aggregation is capable of communicating using the first channel independently of the second channel.

For example, first and second communication channels may each be properly formed in accordance with a given wireless standard and/or wireless scheme. Additional examples include, but are not limited to: A particular communication channel may be considered properly formed when the channel is individually usable by and/or understandable to a legacy wireless device that is not designed to implement channel aggregation. Two aggregated communication channels may be considered properly formed if each includes an independent channel mapping. Also, two aggregated communication channels may be considered properly formed if there is a separate Fast Fourier Transform (FFT) for each aggregated channel. As another example, a properly-formed communication channel may entail including a preamble and/or one or more gaps (e.g., an uplink/downlink gap) in accordance with a wireless air interface technology standard and/or wireless scheme.

In an OFDMA wireless network, for instance, two aggregated channels that are properly formed in accordance with a given OFDMA wireless scheme have separate FFTs. In systems operating in accordance with an OFDMA scheme, each channel usually includes multiple subchannels, with each subchannel being comprised of multiple subcarriers. Channel aggregation may be implemented without using channels that are independent and properly formed if compatibility with legacy and other devices that do not implement channel aggregation is sacrificed. In such implementations, a single FFT can span two channels to thereby effectively bond them.

FIG.2illustrates an example wireless environment200including first and second communication regions202and204that are associated with first and second communication channels110(1) and110(2), respectively. As illustrated, wireless environment200includes a first communication region202and a second communication region204. A first communication channel110(1) is produced in the first communication region202. A second communication channel110(2) is produced in the second communication region204.

Both first and second communication regions202and204are depicted as being substantially circular in shape and concentrically positioned. However, either or both regions may have an alternative shape, such as a sector, and concentric positioning need not be implemented. First communication region202is depicted as being larger than second communication region204. However, either region may be larger, or each region may be the same size. Second communication region204is depicted as being contained within first communication region202. However, either region may fully or only partially overlap the other. In fact, first and second communication regions202and204need not overlap significantly, if at all, as long as a subscriber station is capable of simultaneously communicating via first and second communication channels110(1) and110(2). Furthermore, a single base station102may be creating first and second communication regions202and204and may be transceiving first and second channel aggregated communications110(1) and110(2).

As specifically illustrated inFIG.2, but by way of example only, a base station (BS)102may be realized as a base transceiver station (BTS)206or an access point (AP)208. (As described herein above with particular reference toFIG.1, a base station102may also be realized in other manners.) Implementations of base station102as a BTS206and an AP208are illustrated to describe a specific example.

In this specific example, a BTS206is associated with first communication region202. BTS206produces first communication channel110(1) and transceives via first communication channel110(1). An AP208is associated with second communication region204. AP208produces second communication channel110(2) and transceives via second communication channel110(2). A single subscriber station104may simultaneously communicate with AP208over second communication channel110(2) and with BTS206over first communication channel110(1) in a channel-aggregated scenario. Each of first and second aggregated communication channels110(1) and110(2) are properly-formed such that a wireless device that is unable to understand and/or interoperate with channel aggregation can still share either of first communication channel110(1) or second communication channel110(2).

In a particular exemplary embodiment, first communication region202is designated for licensed communications, and second communication region204is designated for non-exclusively-licensed communications. Hence, in such an embodiment, first communication channel110(1) may be part of a licensed communication band, and second communication channel110(2) may be part of a non-exclusively-licensed communication band. More detailed exemplary embodiments involving licensed and non-exclusively-licensed channel-aggregated communications are described herein below with particular reference toFIGS.10and11.

FIGS.3A and3Billustrate example wireless communication devices including a base station102and a subscriber station104, respectively, which can be utilized to implement embodiments of channel aggregation. Base station102and subscriber station104may be considered wireless communication devices generally. As illustrated, each of base station102and subscriber station104include one or more input/output (I/O) interfaces302, at least one transceiving unit304, at least one processor306, and one or more processor-accessible media308. Media308includes processor-executable instructions310, examples of which may include, but are not limited to, an operating system312and one or more application programs314.

In a described implementation, I/O interfaces302enable communication through wired media and/or a (e.g., secondary) wireless interface. Generally, processor306is capable of executing, performing, and/or otherwise effectuating processor-executable instructions, such as processor-executable instructions310. Media308is comprised of one or more processor-accessible media. In other words, media308may include processor-executable instructions310that are executable by processor306to effectuate the performance of functions by base station102or subscriber station104.

Thus, realizations for channel aggregation may be described in the general context of processor-executable instructions. Generally, processor-executable instructions include programs, applications, coding, modules, objects, interfaces, components, data structures, etc. that perform and/or enable particular tasks and/or implement particular abstract data types. Processor-executable instructions may be located in separate storage media, executed by different processors, and/or propagated over or extant on various transmission media. Moreover, processor-executable instructions may be embodied as software, firmware, hardware, fixed logic circuitry, some combination thereof, and so forth.

Processor(s)306(e.g., any of microprocessors, controllers, etc.) may be implemented using any applicable processing-capable technology. Media308may be any available media that is included as part of and/or accessible by base station102or subscriber station104. It includes volatile and non-volatile media, removable and non-removable media, storage and transmission media (e.g., wireless or wired communication channels), hard-coded logic media (e.g., an application-specific integrated circuit (ASIC), a field programmable gate-array (FPGA), etc.), and so forth. Media308is tangible media when it is embodied as a manufacture and/or a composition of matter. By way of example only, media308may include an array of disks or flash memory for longer-term mass storage of processor-executable instructions, random access memory (RAM) for shorter-term storing of instructions that are currently being executed and/or otherwise processed, link(s) on networks for transmitting communications, and so forth.

FIG.3Aillustrates an example base station102. With base station102, I/O interfaces302provide access to other networks, such as network(s)108(of FIG.1). Network108may be a backhaul network for the wireless network. Base station102also includes a transmitting unit304(T) and/or a receiving unit304(R), which may be termed a transceiving unit304(not separately shown). Transceiving unit304enables base station102to communicate wirelessly via communication links106. Transmitting unit304(T) and receiving unit304(R) may include one or more, and usually multiple, transmitters or receivers, respectively, and/or one or more transmitting chains or receiving chains. Each transmitter and receiver may include one or more radios (not explicitly shown) that are dedicated or shared.

With base station102, processor-executable instructions310are illustrated as including a medium access controller (MAC)316, a scheduler318, and a BS channel aggregation module320. In a described implementation, MAC316plans, orders, regulates, and otherwise controls access to the wireless medium. Scheduler318interacts with a quality of service (QoS) engine (not shown) to determine which services are due some portion of the available bandwidth of the wireless medium. Scheduler318may be part of MAC316. Different implementations having a single MAC or multiple MACs are described herein below with particular reference toFIG.4.

BS channel aggregation module320is responsible for the functions that enable implementation of channel aggregation for two or more channels. In manners that are apparent from the description herein, BS channel aggregation module320interacts with MAC316and/or scheduler318in the performance of some of these channel aggregation functions. For example, during transmission, the division of data between two different aggregated communication channels is determined. During reception, data received on two different aggregated communication channels is recombined into joint or integrated data, perhaps for a single service.

BS channel aggregation module320is also at least partially responsible for announcing that base station102is capable of aggregating two or more channels. For example, this announcement may be in the form of a general broadcast throughout its associated communication region. Alternatively, the announcing may be in the form of a capabilities negotiation with individual subscriber stations, especially with those that indicate they are capable of channel aggregation.

FIG.3Billustrates an example subscriber station104. With subscriber station104, I/O interfaces302provide access through ingress and/or egress ports to data source(s) and/or sink(s)352. Data sources and sinks352may include, for example, a local processing device or memory, a man-machine interface (e.g., keyboard/keypad, speaker, microphone, etc.), a network connection, and so forth. Hence, I/O interfaces302for subscriber station104may be any one or more of a serial and/or parallel interface, a universal serial bus (USB) interface, a wireless interface, a network interface, or any other type of interface for external communication. Examples include, by way of example but not limitation, a network interface card (NIC), a modem, one or more network ports, some combination thereof, and so forth.

Subscriber station104also includes a transmitting unit304(T) and/or a receiving unit304(R), which may be termed a transceiving unit304(not separately shown). Transceiving unit304enables subscriber station104to communicate wirelessly via communication links106. Transmitting unit304(T) and receiving unit304(R) may include one or more transmitters or receivers, respectively, and/or one or more transmitting chains or receiving chains. Having multiple (e.g., at least two) receiving chains and transmitting chains enables a subscriber station104to participate in a channel-aggregated wireless communication. Each transmitter and receiver may include one or more radios (not explicitly shown) that are dedicated or shared.

With subscriber station104, processor-executable instructions310are illustrated as including a SS channel aggregation module354. In a described implementation, SS channel aggregation module354is at least partially responsible for handling channel aggregated communications and performing the SS-side functions of channel aggregation as described herein. For example, SS channel aggregation module354is capable of dividing data over aggregated channels during transmission and combining data into joint or integrated data from two or more aggregated channels during reception. Although not so illustrated specifically, a subscriber station104may also include a MAC and/or a scheduler.

SS channel aggregation module354is also capable of requesting or accepting channel aggregated communications with a base station. For example, SS channel aggregation module354may detect a broadcast notification that a given base station is capable of implementing channel aggregation. Also, SS channel aggregation module354may notify a base station of a channel-aggregating capability during a capabilities negotiation.

FIGS.4A and4Billustrate various components of an example base station, such as the one shown inFIG.3A, that can be configured with a single MAC (FIG.4A) or multiple MACs (FIG.4B). A single MAC configuration316(S) is illustrated inFIG.4A. A multiple MAC configuration316(M) is illustrated inFIG.4B. Each of the illustrated boxes may represent modules and/or applications of processor-executable instructions310.

Single MAC configuration316(S) includes independent physical layers402(1) and402(2) for first aggregated channel110(1) and second aggregated channel110(2), respectively. A physical layer402can include various components, such as a transceiving unit304(ofFIG.3), filtering components, and other components to receive and transmit wireless data. Single MAC configuration316(5) also includes an aggregation layer404, a convergence sublayer406, and a single MAC316*. In this single MAC configuration, MAC316* can include scheduler318.

In single MAC configuration316(S), the single MAC316* is implemented to map the data to the physical resources or to respond to requests by the base station in the uplink. This typically involves an awareness of QoS, destination, state of the physical resources, and so forth. It should be understood that the term “single MAC” refers to two or more channels110/physical layers402in a particular channel-aggregation; a given base station may implement a single MAC configuration316(S) repeatedly for different sectors, different frequency bands, and so forth.

Multiple MAC configuration316(M) includes independent physical layers452(1) and452(2) for first aggregated channel110(1) and second aggregated channel110(2), respectively. Multiple MAC configuration316(M) also includes a respective independent MAC316(1) and316(2) corresponding to each respective physical layer452(1) and452(2). The multiple MAC configuration also includes an aggregation layer454and a convergence sublayer456, which includes scheduler318. In multiple MAC configuration316(M), MACs316(1) and316(2) are implemented to perform many of the same functions as the single MAC316*. It should be understood that scheduler318need not be moved out of the MACs316(1) and316(2) to implement multiple MAC configuration316(M). In fact, scheduler318is moved to convergence sublayer456if a single service is to be split across multiple physical layers452. If the split is to be performed on a per-service basis rather than on a per-packet basis, scheduler318is located in each MAC316(1) and316(2) and convergence sublayer456then directs the packets for a particular service to a particular MAC316(1) or316(2) without truly “scheduling” them.

However, because the decision regarding what channel a packet is transmitted on has already been made (e.g., at convergence sublayer456) in multiple MAC configuration316(M), independent MACs316(1) and316(2) do not perform that aspect of scheduling. In other words, with multiple MAC configuration316(M), some aspects of scheduling are performed at convergence sublayer456while other scheduling aspects are performed at MACs316. Consequently, independent MACs316(1) and316(2) cannot be creative regarding the routing of data based on QoS. This occurs in the convergence sublayer/aggregation modules. It also means that sending automatic retransmit request (ARQ) retries or ACKs on a different channel is not feasible with independent MACs316(1) and316(2). In short, with multiple MAC configuration316(M), some of the complexity of scheduling is split between convergence sublayer456and MACs316(1) and316(2) at the expense of features/flexibility. For example, with multiple MAC configuration316(M), a single service cannot easily be split between the two physical layers452(1) and452(2).

One skilled in the art would understand how to implement layers402,404, and406(and corresponding layers452,454, and456ofFIG.4B) as well as the overall single MAC configuration316(S) (and multiple MAC configuration316(M)) in view of the descriptions and teachings herein. Nevertheless, abbreviated descriptions of the aggregation layer and the convergence sublayer are provided below.

Aggregation layer404/454is relatively thin. It directs the data to/from the correct channel. In single MAC configuration316(S), aggregation layer404is the realization of arrows614between the burst construction queues606/608/610and the subframe structures504/508inFIG.6, which is described herein below. Convergence sublayer406/456determines which subscriber station a packet goes to and on which connection. The next layer down then uses that determination to perform its function. In single MAC configuration316(S), convergence sublayer406passes its information to MAC316* for scheduling at scheduler318. In multiple MAC configuration316(M), convergence sublayer456passes its information to the correct MAC316(1) or316(2).

FIG.5illustrates an exemplary depiction of communication frame structures504,506,508, and510for wireless communication via two aggregated communication channels502(1) and502(2) for an embodiment of channel aggregation. First and second communication channels502(1) and502(2) are specific examples of general first and second communication channels110(1) and110(2) (ofFIG.1). First aggregated communication channel-A502(1) includes a downlink (DL) subframe504and an uplink (UL) subframe506. Second aggregated communication channel-B502(2) includes a DL subframe508and an UL subframe510.

Wireless data for communication with various subscriber stations1-8(SS1-SS8) can be tiled for OFDMA to define a relationship between two frames that are transmitted simultaneously on the two aggregated communication channels502(1) and502(2). In this example, data for subscriber stations3and6(SS3and SS6) are enabled for channel aggregated operation, and data for the other subscriber stations (i.e., SS1,2,4,5,7, and8) are enabled for single channel operation. Although the illustrated frame structures comport with an IEEE 802.16(e) wireless standard implementing TDD OFDMA, the principles are applicable to other air interface technologies and wireless schemes.

In addition to downlink data for the subscriber stations1-8(SS1-8), DL subframes504and508each include respective preambles512(1) and512(2), respective DL maps514(1) and514(2), and respective UL maps516(1) and516(2). In addition to uplink data for the subscriber stations1-8(SS1-8), UL subframes506and510each include a ranging subchannel. Each data burst shown in the subframe structures may contain one or more data packets and/or data packet fragments.

Subscriber station3(SS3) is associated with a number of bursts in subframes504,506,508, and510. First aggregated communication channel-A502(1) includes downlink data for subscriber station3(SS3) at “DL Burst3A”, as indicated at518. Second aggregated communication channel-B502(2) includes downlink data for subscriber station3(SS3) at “DL Burst1B”, as indicated at520. First aggregated communication channel-A502(1) includes uplink data from subscriber station3(SS3) at “UL Burst3A”, as indicated at522. Second aggregated communication channel-B502(2) includes uplink data from subscriber station3(SS3) at “UL Burst1B”, as indicated at524.

Channel aggregation modules320and354(ofFIGS.3A and3B) are responsible for dividing integrated data into two or more sets that are being transmitted across two or more aggregated channels and for combining the data sets that are being received via the two or more aggregated channels into the integrated data. For example, integrated data for subscribe station3(SS3) is divided into first data of “DL Burst3A”518and second data “DL Burst1B”520at a base station. At subscriber station3, the first data of “DL Burst3A” and the second data of “DL Burst1B” are combined into the integrated data.

As illustrated inFIG.5, there can be substantial variability in the mapping of data due to the nature of data traffic, such as IP data traffic. For instance, some subscriber stations may not receive data in every frame, or they may have asymmetric uplink and downlink needs, not only on the average, but also instantaneously on a frame by frame basis. Moreover, there is an additional variability caused by changing parameters at the physical layer. For example, the same data amount may take more or less absolute bandwidth from time to time as conditions of the physical layer vary as a result of how these conditions can impact available modulation and coding rate options. Base station102schedules the bandwidth taking this into account by scheduling the transmission of actual data in the downlink and by scheduling logical demand in the uplink.

FIG.5illustrates an example for how channel aggregation may be implemented in an IEEE 802.16 OFDMA-based system that is operating with a TDD mechanism. However, a FDD mechanism is also effective in an OFDMA system. Moreover, channel aggregation as described herein can be applied to SC, TD-CDMA, and other wireless communication schemes that are identified herein.

FIG.6illustrates an example600of forming data bursts in downlink subframes504and508via two aggregated communication channels502(1) and502(2) in an embodiment of channel aggregation. In this illustrated example of data burst formation600, scheduler318(ofFIG.3) divides the subscriber stations1-8(SS1-8) into three groups602(1,2,3). Group602(1) includes those subscriber stations (e.g., SS1,2,4, and5) that are implemented only for single channel operation and that have accessed the network on first communication channel502(1). Group602(2) includes those subscriber stations (e.g., SS7) that are implemented only for single channel operation and that have accessed the network on second communication channel502(2).

Group602(3) includes those subscriber stations (e.g., SS3and6) that are currently operable for channel aggregated operation on both first and second communication channels502(1) and502(2). In this example, first communication channel502(1) may therefore be considered to be functioning as a standard single communication channel with respect to subscriber stations1,2,4, and5but as a aggregated communication channel with respect to subscriber stations3and6.

Data for the three separate groups602(1,2, and3) of subscriber stations have respective separate class queues604(1,2, and3). These class queues604may be part of a QoS engine (not shown) that is associated with scheduler318of MAC316(all ofFIG.3A). The QoS engine runs initially over the three groups of queues604(1-3) to extract data based on at least one fairness algorithm that has been implemented. In this example, data from group602(1) is allocated/directed from burst construction queue606to first single communication channel502(1) at aggregation layer arrow614(1), and data from group602(2) is allocated/directed from burst construction queue608to second single communication channel502(2) at aggregation layer arrow614(2). Data from group602(3) can be allocated/directed from burst construction queue610to either one or a combination of first and second aggregated communication channels502(1) and502(2) at aggregation layer arrow614(3).

If the downlink subframe504or508for either of the first and second communication channels502(1) or502(2) is individually fully allocated before the combination of communication channels502(1) and502(2) has been fully allocated, the QoS engine or scheduler318closes a gate612(1) or612(2) for the group602(1) or602(2), respectively, that corresponds to the communication channel502(1) or502(2) having a fully-allocated DL subframe. The QoS engine can continue allocating until the combination of data from all three groups602(1-3) fills both communication channels502, or until the time limit for filling the frame has expired. The result is a DL subframe504with data from group602(1) in first communication channel502(1) and a DL subframe508with data from group602(2) in second communication channel502(2). Both DL subframe504and DL subframe508may have data from group602(3) because the data in class queue604(3) is distributed over both first communication channel502(1) and second communication channel502(2).

FIG.7illustrates an example of zone switching700within subframes704,706,708, and710for wireless communication via two aggregated communication channels702for an embodiment of channel aggregation. First aggregated communication channel-A702(1) includes a DL subframe704and an UL subframe706. Second aggregated communication channel-B702(2) includes a DL subframe708and an UL subframe710. First and second aggregated communication channels702(1) and702(2) are specific examples of general first and second communication channels110(1) and110(2) (ofFIG.1).

Although not required to implement channel aggregation, zone switching700may be employed in conjunction with two or more aggregated communication channels702to form a clear demarcation between zones with channel aggregation and zones without. Thus, in a described implementation, a new zone definition provides that the DL and UL subframes can be segregated into zones that are channel aggregated and zones that are not. For example, zone switches712are shown in first aggregated communication channel-A702(1) and second aggregated communication channel-B702(2).

As illustrated, there are three groups: Group1(channel A only), Group2(channel B only), and Group3(channels A and B), with Group3corresponding to the channel-aggregated zones. Zone switch712(1-UL) segregates UL subframe704of first aggregated communication channel-A702(1) into a Group1zone and a Group3zone. Zone switch712(1-DL) segregates DL subframe706of first aggregated communication channel-A702(1) into a Group1zone and a Group3zone. Zone switch712(2-UL) segregates UL subframe708of second aggregated communication channel-B702(2) into a Group2zone and a Group3zone. Zone switch712(2-DL) segregates DL subframe710of second aggregated communication channel-B702(2) into a Group2zone and a Group3zone.

As shown by dashed lines714, the zone switches712may occur at different times (or frequencies) in each subframe on each communication channel702. Also, the temporal (or frequency) location of the zone switches may be adjusted based on demand. For example, zone switching700can be adjusted frame to frame based on the relative demand and QoS constraints of data traffic between channel aggregation and non-channel aggregation subscriber stations. Although not so illustrated, the channel-aggregated zone or zones can precede the non-channel-aggregated zone or zones in any or all of the subframes. Moreover, there can be more or less than the two zones illustrated, and there can be different numbers of zones (including one/none) in different subframes of the same channel or aggregated channels. Furthermore, zone segregation can be performed along a temporal dimension and/or a frequency dimension (e.g., using sets of subcarriers).

FIGS.8and9are flow diagrams800and900, respectively, illustrating example methods related to implementing channel aggregation. Flow diagram800includes three (3) blocks802-806, and flow diagram900includes three (3) blocks902-906. Implementations of these flow diagrams800and900may be realized, for example, as processor-executable instructions310. The actions of flow diagrams800and900may be performed in many different environments and with a variety of wireless communication devices, including by a base station102or a subscriber station104(both ofFIGS.1,3A, and3B). Example implementations for flow diagrams800and900that are described below also refer to other FIGS. that are described elsewhere herein. The order in which the methods are described is not intended to be construed as a limitation, and any number of the described blocks can be combined, augmented, rearranged, and/or omitted to implement a respective method, or an alternative method that is equivalent thereto.

FIG.8is a flow diagram800that illustrates an example method for communication transmission using channel aggregation. At block802, at least two communication channels are aggregated for wireless data communication, with the two communication channels including a first aggregated communication channel and a second aggregated communication channel. For example, a first communication channel110(1) may be aggregated to a second communication channel110(2) (ofFIG.1).

Example communication channel characteristics and communication channel combinations are presented. Communication channels110(1) and110(2) may be adjacent or non-adjacent. Non-adjacent channels may be in the same frequency band or in different bands. Two aggregated communication channels110may be any of the following combinations: licensed (L) and non-exclusively-licensed (NEL), both L, both NEL, and so forth. Furthermore, additional embodiments of channel aggregation may include any two or more aggregated communication channels that have a disparity in transmission power regulation, filtering, or other differences. Other channel characteristics and combinations may alternatively be implemented.

At block804, integrated data is divided for data communication via the first and second channel-aggregated communication channels. For example, data for a single service112may be divided (as at burst construction queue610) into first data for first communication channel502(1) and second data for second communication channel502(2) (ofFIG.6). For instance, integrated data for subscriber station3(SS3) may be divided into a first data set for “DL Burst3A” and a second data set for “DL Burst1B”, as is illustrated inFIG.6. Although an individual subscriber station104need not address communications for multiple other subscriber stations104, each subscriber station104that is participating in a channel-aggregated communication can divide its integrated data into multiple data sets for multiple respective channel-aggregated communication channels, prior to transmission.

At block806, first data is transmitted via the first aggregated communication channel and second data is transmitted via the second aggregated communication channel. For example, first data (e.g., “DL Burst3A” for SS3ofFIG.6) may be transmitted via first aggregated communication channel502(1), and second data (e.g., “DL Burst1B”) may be transmitted via second aggregated communication channel502(2).

In a particular example embodiment, the first data and the second data may be communicated using an OFDMA scheme via non-adjacent, channel-aggregated communication channels. The first data may be transmitted, for instance, via a licensed communication channel for a relatively high quality of service, and the second data may be simultaneously transmitted via a non-exclusively-licensed communication channel for best-effort data communication.

FIG.9is a flow diagram900that illustrates an example method for communication reception using channel aggregation. At block902, first data is received via a first aggregated communication channel, and second data is received via a second aggregated communication channel. For example, first data (e.g., “DL Burst3A” for SS3ofFIG.6) may be received via a first aggregated communication channel502(1) while second data (e.g., “DL Burst1B”) may be simultaneously received via a second aggregated communication channel502(2).

Although the examples given forFIGS.8and9refer to a downlink aggregated channel communication, they are also applicable to an uplink aggregated channel communication. In other words, a subscriber station can also implement the actions of flow diagram800, and a base station can also implement the actions of flow diagram900.

At block904, the first data and the second data are combined into integrated data. For example, the first data and the second data may be combined into integrated data for a single service112at a receiving subscriber station104(or base station102).

At block906, the first data and the second data are ordered in accordance with a predefined ordering scheme. For example, the first data and the second data of each burst may be received in any order, including fully or partially simultaneously. The first and second data sets are thus reordered so as to maintain the intended meaning and coherency of the original integrated data. In other words, the order of the integrated data prior to its division at a transmitting wireless communication device is restored at a receiving wireless communication device.

Generally, a given ordering scheme may be applied at the transmitting wireless device and/or the receiving wireless device. An ordering scheme may be a predefined default ordering, a numbering sequence protocol included with the data, and so forth. By way of example only, a numbering sequence protocol may entail data that is ordered according to an automatic retransmit request (ARQ) numbering sequence protocol that is already included along with the data in some wireless communication schemes. Alternatively, or in addition, the data packets can be ordered according to a special channel-aggregated numbering sequence that is annotated to the data.

More specifically, for a default ordering scheme, all of the data received on a first aggregated channel can be considered logically earlier in a data communication sequence than data received on a second channel, irrespective of which data arrives earlier or a simultaneous arrival on the first and second channels. Also, if the division between aggregated channels is performed on an entire service basis (e.g., all data of one service for a particular subscriber station is sent over a first channel, and all data of another service for the particular subscriber station is sent over a second channel), there is no numbering problem. In general, a predefined ordering scheme is applicable for those services that can have data packets for the same service take different paths. However, a priori knowledge that at least one higher layer already has an order preservation scheme can be used to simplify ordering for data that has been divided for channel aggregation.

For a numbering sequence protocol scheme, data can be ordered by a special channel-aggregating numbering sequence that annotates the data with a channel ordering indicator when communicated via the channel-aggregated communication channels. Alternatively, the data can be ordered using the ARQ numbering sequence protocol when the data is communicated via channel-aggregated communication channels. An ARQ is also commonly referred to as an automatic “resend” request or an automatic “repeat” request. ARQ is a protocol for error control when transmitting data. When a receiving device detects a corrupt data packet, it can automatically request that a transmitting device resend the data packet using the ARQ sequence number. Consequently, an ARQ sequence number can be used for data packet sequence numbering with divided data that is received over two or more aggregated channels, as well as to detect corrupt or missing data. Alternatively, if a higher network layer or level is already known to include a numbering sequence protocol, the numbering from the higher network layer or level may be relied on to maintain an intended order with multiple aggregated channels.

With reference again toFIG.2, a specific example is illustrated as described in detail herein above. In this specific example, a BTS206is associated with a first communication region202. BTS206transceives via first communication channel110(1). An AP208is associated with a second communication region204. AP208transceives via second communication channel110(2).FIGS.10and11illustrate a more particular example in which first communication region202corresponds to a licensed communication region and second communication region204corresponds to a non-exclusively-licensed region. This particular example, without loss of generality, is used to describe other general principles and alternatives of channel aggregation.

FIG.10illustrates an example wireless environment1000that includes a licensed communication region202and multiple non-exclusively-licensed communication regions204, and in which embodiments of channel aggregation can be implemented. By way of example only, the description ofFIGS.10and11refers to region202as a cell. Thus, wireless environment1000includes a licensed communication cell202and multiple overlapping non-exclusively-licensed communication regions204(1-N) that are positioned or located substantially within cell202.

Wireless communication throughout licensed communication cell202is facilitated by BTS206that communicates (e.g., transmits and/or receives) data for wireless communication. Each non-exclusively-licensed communication region204includes a respective wireless AP208(1-N) that facilitates wireless communication within the respective non-exclusively-licensed communication region204(1-N).

BTS206and each of APs208(1-N) can be implemented to operate in a channel aggregated mode in which wireless data is communicated via channel-aggregated communication channels. For example, BTS206can communicate data for wireless data communication in which a first data set is transmitted via a licensed communication channel (within licensed communication cell202) while a second data set is simultaneously transmitted by at least one AP208via a non-exclusively-licensed communication channel (within at least one non-exclusively-licensed communication region204). As is described more fully herein below, utilizing non-exclusively-licensed communication regions204(1-N) can increase overall capacity (e.g., bandwidth) and/or improve diversity gain for wireless data communication, depending on whether different signals or the same signals, respectively, are transmitted within regions204(1-N).

In example wireless environment1000, non-exclusively-licensed communication regions204(1-N) may tend to have a lower allowable transmit power and/or other constraints that are commonly imposed on jointly-used spectrum bands. They are also likely subject to increased communication interference. For increased diversity gain, APs208(1-N) in their respective non-exclusively-licensed communication regions204(1-N) can therefore each be implemented so as to communicate the same data between subscriber stations and the wireless system. In other words, each of the APs208(1-N) that receives data from the wireless system can transmit it on the same non-exclusively-licensed communication channel to subscriber stations within wireless communication range. Hence, a targeted subscriber station can potentially receive multiple versions of the same communication from multiple APs208, especially when the targeted subscriber station is in an overlapping region such as boundary region1010. The non-exclusively-licensed communication channel of APs208can be aggregated to a licensed communication channel being used by BTS206.

FIG.11illustrates examples of channel-aggregated wireless communication in a portion of the environment1000that is shown inFIG.10. The portion shown inFIG.11illustrates part of an example wireless communication system1100having multiple wireless devices including subscriber stations104, a BTS206, and multiple APs208, as well as a data combiner1104. As illustrated, wireless communication system1100includes licensed communication cell202and BTS206that can communicate (e.g., transmit and/or receive) data for wireless data communication. Wireless communication system1100also includes non-exclusively-licensed communication regions204(1-3, N) and respective APs208(1-3, N) that are within the portion of wireless environment1000(ofFIG.10) that is illustrated inFIG.11.

Wireless communication system1100includes examples of subscriber stations104(1-2) that can each communicate (e.g., transmit and/or receive) data for wireless data communication within licensed communication cell202and/or within one or more of non-exclusively-licensed communication regions204. By way of example only, subscriber station104(1) is illustrated as a laptop computer, and subscriber station104(2) is illustrated as an intelligent mobile phone and/or wireless PDA.

Various communication links106are shown between (i) BTS206and APs208(1-3) and (ii) subscriber stations104(1-2) to illustrate channel-aggregated wireless communication between the wireless devices. For example, subscriber station104(2) can communicate first data with BTS206via a licensed communication link106(2-A) that represents a channel-aggregated licensed communication channel. Subscriber station104(2) can also simultaneously communicate second data with AP208(1) via a non-exclusively-licensed communication link106(2-B) that represents a channel-aggregated non-exclusively-licensed communication channel.

In this example with subscriber station104(2), a first aggregated communication channel110(1) (ofFIG.1) corresponds to communication link106(2-A), and a second aggregated communication channel110(2) corresponds to communication link106(2-B). Somewhere within wireless communication system1100, aggregated communication channels110(1) and110(2) are combined, possibly for a single service112. This is described further below with regard to subscriber station104(1).

In the context of channel aggregation, simultaneous communication on two (or more) communication links106and/or two (or more) aggregated channels110(ofFIG.1) implies that communication is occurring at the same moment (e.g., during the same burst periods, frames, subframes, and/or time periods, etc.) at least part of the time. It should be recognized that there are other moments when transceiving may only be occurring on one of the aggregated communications just as their will likely be instantaneous moments when there is no transceiving on any of the aggregated communications, at least with air interface technologies involving some time division of the medium. Consequently, from time to time, certain portions of the first data may arrive prior to portions of the second data, or vice versa.

As another example in wireless communication system1100, subscriber station104(1) can communicate a first data set with BTS206via a licensed communication link106(1-A) that represents a channel-aggregated licensed communication channel. Subscriber station104(1) can also simultaneously communicate a second data set with AP208(2) via a non-exclusively-licensed communication link106(1-B-i) and/or with AP208(3) via a non-exclusively-licensed communication link106(1-B-ii), each of which represents a channel-aggregated non-exclusively-licensed communication channel.

In this example with subscriber station104(1), a first aggregated communication channel110(1) (ofFIG.1) corresponds to communication link106(1-A), and a second aggregated communication channel110(2) corresponds to communication link106(1-B-i) and/or communication link106(1-B-ii). For this example, it is given that each AP208(1-N) is transceiving the same data. Thus, the second data set received via both communication link106(1-B-i) and communication link106(1-B-ii) can be combined using a diversity combining mechanism.

In order to perform this diversity combining, the two versions of the second data set are forwarded to data combiner1104via links1102(2) and1102(3). Data combiner1104may be located at a centralized location, at BTS206, at an AP208, or any other location accessible by wireless communication system1100. These links1102may be wireless links or wired links. When wireless communication system1100is transmitting to a subscriber station104, a data divider or splitter that is analogous to data combiner1104is employed.

With channel aggregation generally, the first data set received via communication link106(1-A) and the second data set received via communication link106(1-B) are combined to form integrated data at data combiner1104. This combination may be performed as part of a channel aggregation module (e.g., BS channel aggregation module320) that is located anywhere within wireless communication system1100, including some centralized data processing facility. This data combination is illustrated generically as data combiner1104. The data combination for diversity combining and the data combination for channel aggregation may be performed at the same location or at different locations. (For a subscriber station104, channel aggregation data combining may be performed by SS channel aggregation module354.)

With channel aggregation data combination, the first data set and the second data set are forwarded (e.g., using a backhaul version of network108) to one location for combining into the integrated data. By way of example only, the second data set can be forwarded from AP(s)208using links1102to BTS206. In this case, links1102may be realized as a wireless signal (including a copied signal that results in APs performing a relay function), a wired signal, a point-to-point microwave signal, some combination thereof, and so forth. If the first data set is forwarded to a third location for combining, a wireless or wired link (not separately shown) from BTS206that is analogous to links1102may be used.

By way of example only, data can be communicated between (i) BTS206and APs208(1-3, N) and (ii) subscriber stations104(1-2) in a point-to-multipoint fashion utilizing OFDMA via the channel aggregated communication channels. The IEEE 802.16 standard is one example of a standard that supports OFDMA systems. Other examples include, but are not limited to, asymmetric digital subscriber line (ADSL) systems, some broadband wireless access systems (e.g., draft standard IEEE 802.22), contemplated 4th Generation (4G) wireless standards (which may include IEEE 802.16), and so forth.

In an example embodiment, channel-aggregating a licensed communication channel and a non-exclusively-licensed communication channel for data communication can take advantage of the non-exclusively-licensed spectrum to effectively increase available bandwidth by an order of magnitude over competitors that may have similar licensed communication spectrums. Further, the aggregated licensed and non-exclusively-licensed communication channels need not be the same width to implement channel aggregation. For example, a 5 MHz licensed communication channel from the WCS band can be aggregated with a 6 MHz non-exclusively-licensed communication channel using unused television signal spectrum, or it can be aggregated with a 10 MHz non-exclusively-licensed communication channel.

Efficiency, improved service, etc. can be gained for wireless data communication when data is communicated via channel-aggregated communication channels. For example, first data having a higher quality need, such as voice or other real-time data, can be transmitted via a relatively higher quality aggregated channel, and second data which is suitable for best efforts can be transmitted via a relatively lower quality aggregated channel. Typically, but not universally, a licensed communication channel has a higher quality of service than a non-exclusively-licensed communication channel. Also, two aggregated non-exclusively-licensed communication channels can have two different quality levels, such as when one is experiencing more interference than the other. In such examples, the communication channel having the lower quality of service is selected for communicating a greater amount of the integrated data.

Alternatively, and on the other hand, data can be primarily communicated via a non-exclusively-licensed communication channel so as to leave the licensed communication channel open to communicate automatic retransmit requests (ARQ) and acknowledgements (ACKs). This can reduce the number of retransmissions while minimizing the data load and thus increasing the apparent bandwidth capacity on the licensed communication channel.

In another example embodiment of channel aggregation, data for wireless communication can be switched from one aggregated channel to another if transmitting and/or receiving conditions change. For instance, data can be communicated primarily via a non-exclusively-licensed communication channel but quickly switched to a aggregated, licensed communication channel if too much interference is encountered on the non-exclusively-licensed communication channel or its quality otherwise decreases.

As mentioned above, each AP208(1-N) may be transmitting and/or receiving the same data or each AP208(1-N) may be transmitting and/or receiving different data. When different data is being transmitted by APs208, there is an automatic capacity gain as each second communication region204effectively becomes a mini-cell. With the same data being transmitted by APs208, capacity is not automatically increased. However, a diversity gain can result, especially in overlapping boundary regions such as boundary region1010(ofFIG.10).

As a subscriber station104roams throughout the licensed communication cell202, the aggregated licensed communication channel remains consistently supported by BTS206while the non-exclusively-licensed communication channel is supported by different APs208as the subscriber station104moves from one non-exclusively-licensed communication region204to an adjacent region204.

Generally, when the same data is being transmitted by each AP208, there are opportunities for statistical multiplexing gains and/or signal path diversity gains, especially when a subscriber station104is located at a boundary between two non-exclusively-licensed communication regions204(1-N), such as at boundary region1010between non-exclusively-licensed communication regions204(3) and204(4). There are also opportunities for diversity gains because multiple, up to all of, APs208(1-N) can receive different versions of the same data from a subscriber station104. These different versions can be combined using any of a number of well known diversity combining mechanisms.

This capacity versus diversity gain implementation option is discussed below in the context of an example channel aggregation between a licensed and a non-exclusively-licensed channel. Usually, non-exclusively-licensed channels have a lower allowable transmit power and are subject to increased interference relative to licensed channels. Overlaying a first communication region202with multiple second communication regions204can effectively use the first issue to mitigate the second issue, as is described below.

InFIGS.10and11, a cell202with a licensed BTS footprint has an underlay comprised of multiple overlapping non-exclusively-licensed AP footprints (204) that are sufficient to substantially cover the licensed BTS footprint. In this example situation, instead of striving for maximum capacity in the non-exclusively-licensed spectrum, the identified goals are increasing robustness and eliminating handoff between these smaller non-exclusively-licensed cells. For this example, it is given that there is channel aggregation of a single licensed channel and a single non-exclusively-licensed channel under the control of a single centralized MAC layer that can distribute traffic appropriately.

To pursue these two identified goals, the non-exclusively-licensed APs in the BTS footprint transmit the same data on the same channel. Any AP that hears a subscriber forwards the data up to the centralized MAC. At the boundaries (e.g., boundary1010) of the non-exclusively-licensed cells, there is likely a diversity gain at the subscriber station's receive because it receives identical data from multiple APs with small differences in arrival time. If properly constructed to do combining at a centralized location, the receiving APs can provide uplink diversity gain. Additionally, a MAC layer diversity gain can be achieved by receiving multiple copies of the same protocol data unit (PDU) from the subscriber station, which can be used to reduce the need for ARQ retransmissions.

This diversity gain effectively enables the non-exclusively-licensed spectrum to be used for additional capacity. Once the additional capacity is achieved, it can be traded off for additional coverage by using stronger codes to achieve robustness at greater distance with the non-exclusively-licensed spectrum adding back the throughput that may be lost. The stronger codes can be ones from a given standard, or, if the standard is extensible, new codes can be utilized if wireless devices on both ends of a link understand the new codes.

The description above presents the capacity increase versus a diversity gain tradeoff as if the only option is for all APs208to transmit the same data or for all APs208to transmit different data. However, an alternative implementation takes a middle ground. This alternative entails selected APs208to be transmitting the same data while other APs208within cell202are transmitting different data. For example, with reference toFIG.11, APs208(2,3, N) may be transceiving the same data with subscriber station104(1) while other APs (e.g.,208(1) and208(4-8)) may be transceiving different data. This enables some statistical multiplexing through a subset of APs208and a capacity gain through other APs208. It does entail some centralized coordination and/or decentralized decision-making, for example using received signal strength and or location techniques to determine which sets of APs208are to communicate with which subscriber stations104.

In short, when APs208transmit the same data and channels, there is no automatic bulk capacity increase, but there can be a multiplexing and a diversity gain. Additionally, there are fewer handovers between APs208, and a greater interference tolerance. When APs208transmit different data, there are no multiplexing or diversity gains, and there is an added handover complexity. However, bulk capacity can be automatically increased.

A capacity increase versus a diversity gain tradeoff implementation option is described relatively qualitatively above. The bulk capacity increase option involves a handover complexity when a subscriber station104moves from one second communication region204to another second communication region204. The diversity gain option forfeits the bulk capacity gain but avoids the handover complexity. This capacity increase versus a diversity gain tradeoff issue is described below relatively quantitatively.

Generally, increasing the capacity of a wireless system is advantageous. The following Equation 1 reflects a system's capacity and is termed the Shannon capacity formula:

C=BW⁢log2(1+SI+N),(Eqn⁢1)
Where S, I, and N denote signal (S), interference (I), and noise (N) power spectral densities, respectively. When the signal, interference, and noise are frequency dependent, the capacity formula becomes as shown in Equation 2:

C=∫0BWlog2⁢(1+S⁡(f)I⁡(f)+N⁡(f)),(Eqn⁢2)

From the formulas above, it is apparent that increasing system bandwidth contributes linearly to the system capacity, whereas increasing the system's SINR contributes only logarithmically to the system capacity. Therefore, when more bandwidth is added to the system, whether as a licensed, non-exclusively-licensed, or other communication channel, the additional bandwidth can be used to linearly increase the system capacity.

With respect to interference considerations, non-exclusively-licensed frequency bands, such as the ISM band at 2.4 GHz may be initially viewed as having a lower capacity due to increased interference. In reality, however, cellular communication systems can suffer from high inter-cell interference that can be only somewhat mitigated by interference cancellation or interference avoidance schemes.

With respect to power considerations, ISM bands for point-to-point communication are limited in the 2.4 GHz ISM band by the amount of directional antenna gain. Practical systems may exhibit 42 dBm transmit power, which is similar to the allowable power in licensed bands sans the antenna gain. In the uplink, the power difference is essentially non-existent as mobile subscribers typically transmit up to 24 dBm, which is less than the FCC limit in most non-exclusively-licensed bands. Consequently, another option for allocating between two aggregated channels is: a non-exclusively-licensed band can be used for the uplink to free-up the licensed band for downlink transmissions.

If a subscriber station104has multiple receive data paths and one transmit data path (e.g., multiple receive chains and one transmitting chain), one of the data receive paths can be allocated to the licensed band and the other data receive path can be allocated to the non-exclusively-licensed band given that the bands are not contiguous. Based on CINR measurements, a base station102can maximize capacity by deciding how best to utilize the two receive chains. With two receive chains that are used in one band, on the other hand, a subscriber station104can use maximum ratio combining (MRC) to reduce the required CINR and thus increase capacity whereas splitting each antenna for different bands increases the available bandwidth.

The following metric can be used as presented in Equation 3:

max⁢{∫0BW⁡(L)log2(1+CINR⁡(L)with⁢2⁢RxΓ),∫0BW⁡(L)log2(1+CINR⁡(L)with⁢1⁢RxΓ)+∫0BW⁡(LE)log2(1+CINR⁡(LE)with⁢1⁢RxΓ)}(Eqn⁢3)
where BW(L) is the bandwidth of the licensed system and .GAMMA. is the gap from capacity that depends on the error correction capability of the system. Similarly, a subscriber station104with one transmit antenna can choose a band based on the metric presented in Equation 4 below:

max⁢{∫0BW⁡(L)log2(1+CINR⁡(L)Γ),∫0BW⁡(LE)log2(1+CINR⁡(LE)Γ)}(Eqn⁢4)
where CINR is measured in the uplink.

Other example channel aggregation implementations, including how data may be directed to each of the multiple aggregated channels, are described below. For example, real-time data such as VoIP can be transceived on a first aggregated channel while non-real-time data can be transceived on a second aggregated channel. The first channel can be a licensed channel, and the second channel can be a non-exclusively-licensed channel, or vice versa. In an OFDMA-based implementation, non-Hybrid Automatic-Repeat-Request (non-HARQ) connections can be transceived on a first aggregated channel while HARQ connections can be transceived on a second aggregated channel. The first channel can be a licensed channel, and the second channel can be a non-exclusively-licensed channel, or vice versa.

As another channel aggregation example with at least first and second aggregated channels, the first aggregated channel can include DL/UL maps and/or control channels for both of the first and second aggregated channels. The second aggregated channel then need only include data in the downlink. This may reduce the likelihood that a subscriber station that is not capable of channel aggregation can utilize either channel, especially the second aggregated channel that does not include a DL/UL map and/or a control channel. The first and second aggregated channels may be non-adjacent.

As yet another channel aggregation example with at least first and second aggregated channels, the first aggregated channel can include an uplink portion while the second aggregated channel does not include an uplink portion. Both of the first and second aggregated channels include a downlink portion. These channels may be adjacent or nonadjacent. This example implementation may be applied to broadcast scenarios in which it may be beneficial to provide greater bandwidth for the downlink communications relative to the uplink communications. Also, an opposite channel-aggregation scenario may be implemented in which of two aggregated channels, both channels have uplink portions, but one omits the downlink portion while the other includes it. Generally, other channel-aggregation scenarios may include alternative numbers of channels and combinations of uplink and downlink portions.

The devices, actions, aspects, features, functions, procedures, modules, schemes, approaches, architectures, components, etc. ofFIGS.1-11are illustrated in diagrams that are divided into multiple blocks. However, the order, interconnections, interrelationships, layout, etc. in whichFIGS.1-11are described and/or shown are not intended to be construed as a limitation, and any number of the blocks can be modified, combined, rearranged, augmented, omitted, etc. in any manner to implement one or more methods, apparatuses, systems, devices, procedures, media, arrangements, etc. for channel aggregation.

Moreover, although systems, apparatuses, devices, media, methods, procedures, techniques, schemes, approaches, arrangements, and other implementations have been described in language specific to structural, logical, algorithmic, and functional features and/or diagrams, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.