Patent Publication Number: US-2013254277-A1

Title: Methods And Networks For Device To Device Communication

Description:
BACKGROUND 
     In peer to peer communications, user equipments (UEs) communicate with each other. Conventional UEs are equipped to transmit on the uplink and receive on the downlink, while base stations receive on the uplink and transmit on the downlink. Peer to peer communication may be used for at least public safety and social networking. 
     To improve public safety, peer to peer communication is used where the cellular infrastructure is unavailable. Peer to peer communication allows user equipments (UEs) to communicate with each other directly in emergency situations. 
     Peer to peer communication is also used in social networking. More specifically, peer to peer communication allows proximate UEs have to share information. 
     SUMMARY 
     Example embodiments are directed to methods and networks for peer to peer communication. The methods and networks permit an operator of the network to control peer to peer communications. 
     In one example embodiment, user equipments (UEs) are augmented with a base station receive function. In other words, the UEs are configured to receive data on an uplink transmission channel. 
     In addition to conventional transmission from the base station to the UEs on the downlink and transmission by UEs on the uplink to the base station, a direct communication link between UEs is supported on the uplink spectrum. The duplexing method used to enable both transmission and reception by UEs on the uplink channel can be implanted in the time domain, frequency domain or code domain, or any combination thereof. Concurrent transmission and reception by the UEs on the same frequency and at the same time is enabled by adding an interference cancellation capability at the UEs. In the absence of such cancellation capability, the transmissions of the UE are separated from the receptions to the UE using any combination of time, frequency or code separation. 
     A control path for the direct communication link is a pair of bi-directional links between a base station and each of the UEs in the direct-communication pair. 
     At least one example embodiment discloses a method of controlling communications between first and second user equipments (UEs) by a base station in a network. The method includes obtaining an indication, the indication indicating if the first and second UEs are within a communication range of each other and controlling a direct communication link between the first and second UEs if the first and second UEs are within a communication range of each other. The controlling includes allocating at least a first portion of an uplink channel of the network to the direct communication link. 
     In one example embodiment, the controlling a direct communication link includes transmitting control information over a control path. 
     In one example embodiment, the control path includes a bi-directional link between the base station and the first UE and a bi-directional link between the base station and the second UE. 
     In one example embodiment, the controlling a direct communication link includes transmitting transmission parameters for the direct communication link to the first and second UEs. 
     In one example embodiment, the transmitting transmission parameters includes transmitting a same set of transmission parameters assigned for the first and second UEs for the direct communication link to the first and second UEs. 
     In one example embodiment, the transmission parameters are based on the UE. 
     In one example embodiment, the transmission parameters include a duplex mode, the duplex mode being a full-duplex or a half-duplex. 
     In one example embodiment, the controlling a direct communication link includes transmitting reception parameters for the direct communication link to the first and second UEs. 
     In one example embodiment, the method further includes receiving data from the first UE and transmitting the data to the second UE. The second UE is configured to only receive data on a downlink. 
     In one example embodiment, the method further includes transmitting information on a downlink to the first UE while the first UE monitors communications on the direct communication link. 
     In one example embodiment, the controlling a direct communication link includes transmitting reception parameters for the direct communication link to the first and second UEs. 
     At least one example embodiment discloses a first user equipment (UE) configured to receive data from a peer UE over an uplink channel of a network. 
     In one example embodiment, the first UE is configured to receive control information for reception over a bi-directional link between the first UE and a base station. 
     In one example embodiment, the first UE is configured to listen in designated slots of an uplink of the network. 
     In one example embodiment, the first UE is configured to receive transmission parameters from a base station and is configured to determine reception parameters for the uplink channel based on the transmission parameters. 
     In one example embodiment, the first UE is configured to directly communicate with the peer UE in a half-duplex mode. 
     In one example embodiment, the first UE is configured to directly communicate with the peer UE in a full-duplex mode. 
     At least one example embodiment discloses a base station configured to determine if first and second equipments (UEs) are within a communication range of each other, control a direct communication link between the first and second UEs if the first and second UEs are within a communication range of each other and allocate at least a first portion of an uplink channel of a network to the direct communication link. 
     In one example embodiment, the base station is further configured to transmit transmission parameters for the direct communication link to the first and second UEs. 
     In one example embodiment, the base station is further configured to transmit a same set of transmission parameters assigned for the first and second UEs for the direct communication link to the first and second UEs. 
     In one example embodiment, the base station is further configured to transmit reception parameters for the uplink channel of the direct communication link to the first and second UEs. 
     In one example embodiment, the base station is further configured to transmit reception parameters for the uplink channel of the direct communication link to the first and second UEs. 
     In one example embodiment, the first portion of the uplink channel is a portion of uplink spectrum of the network. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Example embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.  FIGS. 1-3  represent non-limiting, example embodiments as described herein. 
         FIG. 1  illustrates an example embodiment of a network; 
         FIG. 2A  illustrates an example embodiment of a UE with base station receiving functionality; 
         FIG. 2B  illustrates an example embodiment of a base station; and 
         FIG. 3  illustrates a method of controlling communications between first and second UEs according to an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Various example embodiments will now be described more fully with reference to the accompanying drawings in which some example embodiments are illustrated. 
     Accordingly, while example embodiments are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but on the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the claims. Like numbers refer to like elements throughout the description of the figures. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof. 
     It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Portions of example embodiments and corresponding detailed description are presented in terms of software, or algorithms and symbolic representations of operation on data bits within a computer memory. These descriptions and representations are the ones by which those of ordinary skill in the art effectively convey the substance of their work to others of ordinary skill in the art. An algorithm, as the term is used here, and as it is used generally, is conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of optical, electrical, or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. 
     In the following description, illustrative embodiments will be described with reference to acts and symbolic representations of operations (e.g., in the form of flowcharts) that may be implemented as program modules or functional processes including routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types and may be implemented using existing hardware at existing network elements or control nodes. Such existing hardware may include one or more Central Processing Units (CPUs), digital signal processors (DSPs), application-specific-integrated-circuits, field programmable gate arrays (FPGAs) computers or the like. 
     Unless specifically stated otherwise, or as is apparent from the discussion, terms such as “processing” or “computing” or “calculating” or “determining” or “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical, electronic quantities within the computer system&#39;s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices. 
     Note also that the software implemented aspects of example embodiments are typically encoded on some form of tangible (or recording) storage medium. The tangible storage medium may be magnetic (e.g., a floppy disk or a hard drive) or optical (e.g., a compact disk read only memory, or “CD ROM”), and may be read only or random access. Example embodiments are not limited by these aspects of any given implementation. 
     As used herein, the term “user equipment” (UE) may be synonymous to a mobile user, mobile station, mobile terminal, user, subscriber, wireless terminal and/or remote station and may describe a remote user of wireless resources in a wireless communication network. The term “base station” may be understood as a one or more cell sites, enhanced Node-Bs (eNB), base stations, access points, and/or any terminus of radio frequency communication. Although current network architectures may consider a distinction between mobile/user devices and access points/cell sites, the example embodiments described hereafter may generally be applicable to architectures where that distinction is not so clear, such as ad hoc and/or mesh network architectures, for example. 
     The term “channel” may be understood as any combination of frequency band allocation, time allocation and code allocation. 
       FIG. 1  illustrates an example embodiment of a network. As shown in  FIG. 1 , a network  100  includes a base station  110  and UEs  120   a ,  120   b  and  120   c . The base station  110  may be an eNB, for example. The system  100  may be a time division duplexed (TDD) or frequency division duplexed (FDD) system. 
     Each UE  120   a - 120   c  communicates with the base station  110  via bi-directional communication links  130   a ,  130   b , and  130   c , respectively. Each of the bi-directional links includes an uplink  130   a   1 ,  130   b   1  and  130   c   1  and a downlink  130   a   2 ,  130   b   2 , and  130   c   2 . 
     The downlinks  130   a   2 ,  130   b   2 , and  130   c   2  are channels from the base station  110  to the UEs  120   a - 120   c , respectively. The base station  110  transmits on the downlinks  130   a   2 ,  130   b   2 , and  130   c   2 , and the UEs  120   a - 120   c  receive on the downlinks  130   a   2 ,  130   b   2 , and  130   c   2 , respectively. 
     The uplinks  130   a   1 ,  130   b   1  and  130   c   1  are channels from the UEs  120   a - 120   c  to the base station  110 . The UEs  120   a - 120   c  transmit on the uplinks  130   a   1 ,  130   b   1  and  130   c   1 , respectively, and the base station  110  receives on the uplinks  130   a   1 ,  130   b   1  and  130   c   1 . 
     In frequency division duplex (FDD) the links  130   a ,  130   b  and  130   c  are separated in spectrum: one part of the spectrum is allocated to the uplink and another part of the spectrum is allocated to the downlink. 
     In time division duplex (TDD), the channels are separated in time, but occupy the same spectrum. Transmit and receive functions of the UE are alternated in different assigned time slots. In an FDD configuration, the UEs  120   a - 120   c  can transmit and receive simultaneously. In half-duplex mode the each UE  120   a - 120   c  either receives or transmits, having some radio modules of combined functionality. While some example embodiments have been described with reference to FDD and/or TDD, it should be understood that example embodiments should not be limited thereto and any other known method such as code division or orthogonal frequency-division multiplexing (OFDM), may be used. 
     In various example embodiments, UEs may include base station receiving and/or transmitting functions. The base station receiving function is the ability to receive data that has been transmitted on the uplink channel by a UE. The Base Station transmitting function is the ability to transmit data over the downlink channel in a manner that can be decoded by the UE. 
     In the time division duplexed (TDD) mode, a UE emulates base station functions by changing times of transmission and reception to some negotiated subset of the base station transmission and reception intervals. The negotiation here is between the base station and the UE intending to emulate base station operation. The base station mutes or powers down its transmitter during the time intervals that it assigns to the base station emulating-UE. The base station does not schedule transmissions by UEs attached to it, during these negotiated quiet periods. On the uplink, a UE transmitting to the base station can swap any transmissions destined for the base station emulating-UE. 
     In a frequency division duplexed (FDD) mode, the transmit and receive frequencies for the UE are switched for base station emulation. 
     Therefore, the UE contains an additional transmitting and receiving chain to permit such operation. 
     In the example embodiment shown in  FIG. 1 , the UEs  120   a  and  120   b  include the base station receiving functions and the UE  120   c  does not include base station functionality. Thus, the UEs  120   a  and  120   b  may receive communications across a combination of uplink channels and downlink channels of the network. 
     Direct Communication Between UE  120   a  and UE  120   b    
     Since the UEs  120   a  and  120   b  include base station receiving functionality, neither of the communicating UEs  120   a  and  120   b  emulates a base station transmitter. Each of the communicating UEs  120   a  and  120   b  emulates a base station receiver (e.g., receives on an uplink channel) in order to receive data from a UE peer. The base station  110  decides the uplink channel on which to receive by controlling the UEs  120   a - 120   c  to transmit on the designated uplink channels  130   a   1 ,  130   b   1 , and  130   c   1 , respectively. 
     The UEs  120   a  and  120   b  do not transmit while they are listening. Because neither of the UEs  120   a  and  120   b  transmits on the respective downlink channel  130   a   2  and  130   b   2 , communication between the UEs  120   a  and  120   b  exists without emulating a base station transmitter. 
     Each of the UEs  120   a  and  120   b  may perform a discovery method to discover UEs within a communication range. Alternatively, the base station  110  may initiate a discovery method to determine which UEs are within a communication range. The discovery process may be any known method of discovering peers. If one of the UEs  120   a  and  120   b  discovers that the other UE is within the communication range, the one of the UEs  120   a  and  120   b  may request direct communication. 
     In  FIG. 1 , each of the UEs  120   a - 120   c  is considered to be within a communication range of each UE  120   a - 120   c.    
     Because the UEs  120   a  and  120   b  are within a communication range, at least one of the UEs  120   a  and  120   b  transmits a request for direct communication to the base station  110  through the respective link  130   a  and  130   b . In response to the request, the base station  110  initializes a direct communication link  140  by transmitting control information to the UEs  120   a  and  120   b  over a control path. The control path for the direct communication link  140  includes the bi-directional communication link  130   a  and the bi-directional communication link  130   b.    
     Because the base station  110  controls the direct communication link  140 , no user data is required to be transmitted across the communication links  130   a  and  130   b . User data may be transmitted over the direct communication link  140 . 
     The control path may be used by the base station  110  to discover proximate neighbors of each UE, assign the communication schedule and transmission parameters. The base station  110  can seamlessly disconnect the direct communication link  140  and replace it with a bearer-path (e.g., links  130   a ,  130   b  and  130   c ) passing through the base station  110  if overall system performance is degraded by the direct communication link  140 . 
     The control information includes the transmission parameters for the direct communication link  140 . The transmission parameters may also be referred to as a transmission channel configuration and may identify one or more of power level, data rate of transmission, coding and modulation format, code space, bandwidth and time slot allocation, duration of grant for direct communication, and other transmission parameters, for example. 
     More specifically, the direct communication link  140  includes links  140   a  and  140   b . The UE  120   a  transmits information to the UE  120   b  over the link  140   a  and the UE  120   b  transmits information to the UE  120   a  over the link  140   b . Once the direct communication link  140  is established by the base station  110 , a portion of the uplink  130   a   1  is allocated to the link  140   a . Thus, the UE  120   a  transmits over the link  140   a  using the same channel configuration (e.g., same frequency, code, transmission slot) as the uplink  130   a   1 , except at a lower transmit power sufficient to reach the UE  120   b . Consequently, the transmission channel configuration may be controlled from the base station  110  using any known method to control the uplinks  130   a   1 ,  130   b   1  and  130   c   1 . A portion of the uplink  130   b   1  is allocated to the link  140   b , by the base station  110 , in the same manner as the portion of the uplink  130   a   1  is allocated to the link  140   a.    
     The base station  110  determines the allocation of all or part of the uplink channels  130   a   1 ,  130   b   1 , and  130   c   1  among the UEs  120   a - 120   c  in the system  100  based on a resource management function at the base station  110 . Moreover, the base station  110  may determine the designated listening slots for the UEs  120   a  and  120   b . Any known resource management function may be used. The known resource management function is implementation specific and is based on resources of the network while limiting the interference caused by transmissions by the UEs. 
     Based on the transmission parameters, each UE  120   a  and  120   b  transmits on the direct communication link  140  according to the transmission channel configuration of the direct communication link  140 . The receiving UE in the direct communication link  140  listens on the uplink channel using the uplink transmit configuration associated with which the receiving UE expects to receive transmissions from the transmitting UE in the direction communication link  140 . For example, the UE  120   b  listens on the link  140   a  based on the configuration of the uplink  130   a   1 . 
     In one example embodiment, the base station  110  transmits a same set of transmission parameters assigned for the UEs  120   a  and  120   b  for the direct communication link  140  to the UEs  120   a  and  120   b . In other words, the base station  110  transmits the transmission parameter for the UE  120   b  to the UE  120   a  and vice versa. Since each UE  120   a  and  120   b  receives the same set of transmission parameters, each UE  120   a  and  120   b  recognizes when and how the other UE is transmitting. Consequently, the UEs  120   a  and  120   b  may recognize the designated uplink channel to listen for transmissions across the direct communications link  140 . 
     Alternatively, the base station  110  transmits reception parameters to the UEs  120   a  and  120   b  for the direct communication link  140 , in addition to the transmission parameters, as part of the control information. For example, the reception parameters indicate which channel the UEs  120   a  and  120   b  are to listen on the direct communication link  140 . 
     Once the UEs  120   a  and  120   b  receive the transmission parameters and, if applicable, the reception parameters, the UEs  120   a  and  120   b  may directly communicate across the direct communication link  140 . For example, the direct communications link  140  may be full duplex in time if the UEs  120   a  and  120   b  include interference cancelling, which allows the UEs  120   a  and  120   b  to transmit and receive on the same frequency band at the same. 
     Since the UEs  120   a  and  120   b  are equipped with only base station receiving function, the equipment complexity is lower compared to UEs equipped with base station transmitting and receiving functions. 
     Furthermore, the UE  120   c , which is in the vicinity of the peering UEs  120   a  and  120   b  can continue to communicate with the base station  110  since additional transmission occurs on the downlink from the base station  110 . 
     Direct Communication Between UE  120   a  and UE  120   c    
     The direct communication between the UE  120   a  and the UE  120   c  is substantially similar to the direct communication between the UE  120   a  and the UE  120   b . Therefore, only the differences will be described, for the sake of brevity. 
     In  FIG. 1 , the UE  120   a  includes base station receiving functions and the UE  120   c  does not include base station functionality. The base station  110  initializes a direct communication link by transmitting control information to the UEs  120   a  and  120   c  over a control path. The direct communication link between the UE  120   a  and the UE  120   c  includes a forward link, which includes the links  130   a   1  and  130   c   2 , and a reverse link  150 . 
     The control path for the direct communication link  130  includes the bi-directional communication link  130   a  and the bi-directional communication link  130   c.    
     Because the UE  120   c  does not have the base station receiving function, the base station  110  transmits transmission parameters to the UE  120   a  indicating that the reverse link of the communications link from the UE  120   a  to the UE  120   c  should go through the base station  110  before reaching the UE  120   c , and will include the links  130   a   1  and  130   c   2 . The reverse link of the communication link from the UE  120   c  to the UE  120   a  will follow direct communications link  150 , instead of following the conventional path  130   c   1  and  130   a   2 . 
     In one example embodiment, the base station transmits a same set of transmission parameters assigned for the UEs  120   a  and  120   c  for the direct communication link to the UEs  120   a . Since the UE  120   a  receives the set of transmission parameters, assigned for each UE  120   a  and  120   c , the UE  120   a  recognizes when and with what characteristics the other UE  120   c  is transmitting. Consequently, the UE  120   a  may recognize the designated slots, frequency, code, and combination of the above allocated for the uplink transmission channel of the UE  120   c  to listen for transmissions across the direct communications link  150 . The base station  110  conventionally sends a set of transmission and reception parameters to the UE  120   c  over the forward link  130   c   2 , which will describe configuration of the transmission channel  150  and the receiving channel  130   c   2 . 
     Alternatively, the base station transmits reception parameters to the UEs  120   a  and  120   c  for the direct communication link, in addition to the transmission parameters, as part of the control information. 
     For example, the base station  110  sends the reception parameters to the UE  120   a  over the link  130   a   2  of the control path indicating that the reverse link  150  (communications from the UE  120   c ) will be initiated by the UE  120   c  as the forward link, and can be received directly by the UE  120   a.    
       FIG. 2A  illustrates an example embodiment of the UE  120   a  with base station receiving functionality. While only the UE  120   a  is shown, it should be understood that the UE  120   b  may have the same structure. It should be also understood that the UE  120   a  may include features not shown in  FIG. 2A  and should not be limited to those features that are shown. 
     The UE  120   a , shown in  FIG. 2A , is configured to receive data from a peer UE (e.g., the UE  120   b ) over an uplink channel of a network. The UE  120   a  is configured to receive control information for reception over a bi-directional link between the first UE and a base station. The UE  120   a  is configured to listen in designated slots of an uplink of the network. The UE  120   a  is configured to receive transmission parameters from a base station and is configured to determine reception parameters based on the transmission parameters. The UE  120   a  is configured to directly communicate with the peer UE in a half-time-duplex mode. The UE  120   a  is configured to directly communicate with the peer UE in a full-time duplex mode. 
     The UE  120   a  may include, for example, a transmitting unit  210 , a UE receiving unit  220 , a base station receiving unit  225 , a memory unit  230 , a processing unit  240 , and a data bus  250 . 
     The transmitting unit  210 , UE receiving unit  220 , base station receiving unit  225 , memory unit  230 , and processing unit  240  may send data to and/or receive data from one another using the data bus  250 . The transmitting unit  210  is a device that includes hardware and any necessary software for transmitting wireless signals on the uplink (reverse link) including, for example, data signals, control signals, and signal strength/quality information via one or more wireless connections to other wireless devices (e.g., base stations). 
     The UE receiving unit  220  is a device that includes hardware and any necessary software for receiving wireless signals on the downlink (forward link) channel including, for example, data signals, control signals, and signal strength/quality information via one or more wireless connections from other wireless devices (e.g., base stations). The UE receiving unit  220  receives control information for reception over the bi-directional link  130   a  between the UE  120   a  and the base station  110 . The UE  120   a  listens in designated slots of an uplink (reverse link) of the network. 
     The base station receiving unit  225  is implemented as a receiver chain including a low noise amplifier, mixer, filter, and baseband processor configured to receive signals transmitted on an uplink channel. 
     The memory unit  230  may be any storage medium capable of storing data including magnetic storage, flash storage, etc. 
     The processing unit  240  may be any device capable of processing data including, for example, a microprocessor configured to carry out specific operations based on input data, or capable of executing instructions included in computer readable code. The processing unit  240  may determine reception parameters based on the transmission parameters. 
       FIG. 2B  illustrates an example embodiment of the base station  110 . It should be also understood that the base station  110  may include features not shown in  FIG. 2B  and should not be limited to those features that are shown. 
     Referring to  FIG. 2B , the base station  110  may include, for example, a data bus  259 , a transmitting unit  252 , a receiving unit  254 , a memory unit  256 , and a processing unit  258 . 
     The transmitting unit  252 , receiving unit  254 , memory unit  256 , and processing unit  258  may send data to and/or receive data from one another using the data bus  259 . The transmitting unit  252  is a device that includes hardware and any necessary software for transmitting wireless signals including, for example, data signals, control signals, and signal strength/quality information via one or more wireless connections to other network elements in the wireless communications network  100 . For example, the transmitting unit  252  transmits the transmission parameters for the direct communication links  140  and  150  to the UEs  120   a - 120   c , respectively. If applicable, the transmitting unit  252  also transmits the reception parameters for the direct communication links  140  and  150 . 
     The receiving unit  254  is a device that includes hardware and any necessary software for receiving wireless signals including, for example, data signals, control signals, and signal strength/quality information via one or more wireless connections to other network elements in the network  100 . 
     The memory unit  256  may be any device capable of storing data including magnetic storage, flash storage, etc. 
     The processing unit  258  may be any device capable of processing data including, for example, a microprocessor configured to carry out specific operations based on input data, or capable of executing instructions included in computer readable code. 
     For example, the processing unit  258  is capable of determining when UEs are within a communication range. The processing unit  258  is also configured to control the control paths and the direct communication links  140  and  150 . More specifically, the processing unit  258  determines the transmission parameters and, if applicable, the reception parameters. Consequently, the processing unit  258  allocates at least a first portion of an uplink channel of a network to a direct communication link. 
       FIG. 3  illustrates a method of controlling communications between first and second UEs. The method shown in  FIG. 3  may be performed by the base station  110  shown in  FIG. 1 . In the method of  FIG. 3 , the first UE is enhanced with a base station receiving function (e.g., the UE  120   a ). 
     As shown, at  5310 , the base station obtains an indication. The indication indicates if the first and second UEs are within a communication range of each other. In one example embodiment, the first UE may perform a discovery method. Once the first UE discovers a UE (e.g., the second UE) is within a communication range, the first UE may transmit the indication to the base station. The indication also includes a request for direct communication with the second UE. If the second UE is enhanced with the base station receiving function (e.g., receive communications on the uplink channel), it should be understood that the second UE may also perform the discovery method. 
     In another example embodiment, the base station may perform the discovery method and determine that the first and second UEs are within a communication range of each other. If the first and second UEs are within the communication range, the base station informs the first and second UEs that they are within the communication of each other. In response, at least one of the first and second UEs may request direct communication between the first and second UEs. 
     Any known discovery method can be used such as in an ad-hoc mode of Wi-Fi, paring mode of Bluetooth systems or commercial wireless systems where a base station mediates communication between two UEs. Moreover, it should be understood that example embodiments should not be limited to the discovery methods explicitly recited herein. 
     Once the base station receives the indication, the base station controls a direct communication link between the first and second UEs, at  5320 . 
     If the base station recognizes that the second UE does not include a base station receiving function, it may assist in establishing a direct transmission link from the second UE to the first UE and the conventional communications link from the first UE through the Base Station to the second UE. 
     The base station transmits control information over a control path. The control path includes a first bi-directional link between the base station and the first UE and a second bi-directional link between the base station and the second UE. The control information includes the transmission parameters. 
     Moreover, when the second UE is not enhanced with the base station receiving function, the base station transmits the transmission parameters to the first UE indicating that a forward link of the direction communications link from the first UE to the second UE should to reach the base station before reaching the second UE. 
     In one example embodiment, the base station transmits a same set of transmission parameters assigned for the first and second UEs for the direct communication link to the first and second UEs. Since each UE receives the same set of transmission parameters, each UE recognizes when the other UE is transmitting. Consequently, the first and second UEs may recognize the designated slots to listen for transmissions across the direct communications link for the first and second UEs. For example, since the first UE is configured to receive communications on the uplink channel, the first UE may listen for communications across the direct communication during the time slots the second UE is transmitting. 
     Alternatively, the base station transmits reception parameters to the first and second UE, in addition to the transmission parameters, as part of the control information. 
     For example, the base station sends the reception parameters to the first UE over the first bi-directional link of the control path indicating that a reverse link of the direct communications link (communications from the second UE) will be initiated by the second UE as the forward link, and can be received directly by the first UE. 
     The direct communications link is a data path that is either full or half-duplexed in time or frequency on the uplink. For example, the direct communications link may be full-duplexed in time if the first and second UEs include interference cancelling, which allows the first and second UEs to transmit and receive on the same frequency band at the same time. 
     The base station communicates the channel assignment parameters to the second UE in a conventional way. 
     As the result, the first UE receives the transmission from the second UE directly across a portion of the upstream channel, while second UE receives the communications from the first UE through the base station. In other words, the transmit power of the second UE is significantly reduced in order to only accommodate local direct mode reception by the first UE in close proximity, thus providing the gain. 
     As described, the methods and networks of example embodiments permit an operator of the network to control peer to peer communications. 
     In at least one example embodiment, user equipments (UEs) are augmented with a base station receive function. In other words, the UEs are configured to receive data on an uplink transmission frequency. 
     A direct communication link between UEs is supported by the uplink spectrum. A half-duplex mode is used when the UEs are not equipped with self-interference cancellation technology. A full-duplex mode can be used when UEs are capable of self-interference control. 
     A control path for the direct communication link is a pair of bi-directional links between a base station and each of the UEs in the direct-communication pair. 
     Example embodiments being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of example embodiments, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims.