Patent Publication Number: US-10791171-B2

Title: Context-aware proximity services

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/844,689, filed Jul. 10, 2013, the disclosure of which is hereby incorporated by reference as if set forth in its entirety herein. 
    
    
     BACKGROUND 
     Peer-to-peer (P2P) proximity communication may refer to infrastructure-based or infrastructure-less communications between peers within a proximity of each other. A peer may refer to a user or a device such as, for example, a mobile station (MS) in a 2G system, or a full-function device (FFD) or reduced-function device (RFD) in a IEEE 802.15 wireless personal area network (WPAN). Examples of P2P devices include connected cars, medical devices, smart meters, smart phones, tablets, laptops, game consoles, set-top boxes, cameras, printers, sensors, home gateways, and the like. P2P proximity communication may focus on a peer being aware of its proximity for desired services in an infrastructure-based or infrastructure-less configuration. For example, P2P communications may be implemented in a centralized system that includes a centralized controller or a fully distributed system without a central controller. In contrast to infrastructure-less P2P communications, infrastructure-based communications often include a centralized controller, for example, for handling user information, scheduling among users, and managing connections (e.g., cellular communications). In infrastructure-less P2P communications, peers typically have equal responsibility for initiating, maintaining, and terminating a communication session. Proximity-based applications and services represent a recent socio-technological trend. P2P proximity communications are used in various implementations including, for example, social networking, advertising, emergency situations, gaming, smart transportation, and network to network scenarios. 
     In typical social network implementations, peers in proximity can interact with each other at the application level (e.g., Facebook, Twitter). Two-way communication among two or more peers is often required in social network implementations of P2P proximity communications. Traffic data rates may be low (e.g., text-based chatting) or high (e.g., content sharing). In an example advertising implementation of P2P proximity communications, a store broadcasts its promotions and coupons to potential customers (peers) who are within a proximity to the store&#39;s location. In this example scenario, one-way communication with low data traffic is typical, but two-way communication may be used (e.g., for personalized advertisements). 
     Implementation of P2P proximity communications in emergency situations usually involves one-way communication, such as an emergency alarm for example. Other emergency implementations need two-way communication, such as during an emergency safety management scenario. An emergency service/application of P2P may have higher priority than other P2P services/applications, and some emergency services/applications may have higher privacy requirements. In an example gaming implementation of P2P, multiple peers initialize or participate in interactive games, such as multiplayer gaming (online or otherwise) following certain rules for example. Interactive P2P gaming often requires low latency. In an example smart transportation implementation of P2P proximity communication, connected cars via car-to-car and/or car-to-infrastructure communication can support advanced applications including, for example, congestion/accident/event notification, interactive transportation management such as carpooling and train scheduling, smart traffic control, and the like. Data rates in smart transportation implementations are often low, but smart transportation may require highly reliable message delivery and very low latency. Network to Network P2P may be used for extending the coverage of infrastructure or offloading from infrastructure. 
     The example implementations of P2P communications described above may relate to machine-to-machine (M2M) and Internet of Things (IoT) applications or services. The IoT introduces objects or things to Human-to-Human (H2H) based Internet services. It marks a stage of the Internet where physical or virtual objects are interconnected to enable the Internet of Services (IoS). Many of these services are proximity based, such as smart shopping, smart home, smart office, smart health, smart transportation, smart parking, smart grid, and smart city, among other things. 
     Proximity services may be based on peer-to-peer (P2P) communications in proximity. P2P devices include tablets, smart phones, music players, game consoles, personal digital assistances, laptops/PCs, medical devices, connected cars, smart meters, sensors, gateways, monitors, alarms, set-top boxes, printers, Google glasses, drones, and service robots, among other things. A P2P communication system may be a central system with a controller or core network serving as an infrastructure, or a distributed system without a controller or core network serving as the infrastructure. Proximity services may include human-to-human (H2H) proximity services, machine-to-machine (M2M) proximity services, machine-to-human (M2H) proximity services, human-to-machine (H2M) proximity services, and network of network proximity services. 
     Proximity-based applications and services represent a trend to offload heavy local internet traffic from a core infrastructure as well as provide the connections to an infrastructure via multi-hopping. Many standards have identified proximity services use cases as part of their standardization working groups, such as 3GPP, oneM2M, IETF, IEEE, and OMA for example. 
     Existing wireless systems that provide at least some support to P2P communication include, for example, Bluetooth, Wi-Fi ad hoc mode, and Wi-Fi direct. Bluetooth refers to a wireless technology standard for exchanging data over short distances from fixed and/or mobile devices by creating personal area networks (PANs). This technology is often useful when transferring information between two or more devices that are within a proximity to each other, wherein the information is transferred at a low data rate. Bluetooth is a packet-based protocol with a master-slave structure. One master may communicate with up to 7 slaves in a piconet. The master chooses which slave device to address, typically in a round-robin fashion. A slave may listen in each receive slot. Being a master of seven slaves is possible. Being a slave of more than one master may be difficult, for example, because slave devices may have one connection at a time, while master devices may have multiple connections with different slave devices simultaneously. 
     Wi-Fi ad hoc mode is also known as Independent Basic Service Set (IBSS). Wi-Fi ad hoc mode consists of local wireless devices (nodes) discovering each other and forming a network, wherein each node can forward data for other nodes. In ad hoc mode, wireless client machines connect to one another in order to form a peer-to-peer network in which the machines may act as both a client and an access point at the same time. Unlike Wi-Fi infrastructure mode, ad hoc mode has no distribution system that can send data frames from one station to another. Thus, an IBSS may be defined as a restricted wireless network. 
     Wi-Fi direct devices are able to communicate with each other without requiring a wireless access point. The Wi-Fi direct devices may negotiate when they first connect to each other to determine which device acts as an access point. Wi-Fi direct essentially embeds a software access point (“Soft AP”) into any device that supports direct Wi-Fi. The soft AP provides a version of Wi-Fi protected setup with its push-button or PIN-based setup. Devices can make a one-to-one connection, or a group of several devices can connect simultaneously. 
     Current wireless systems, such as Bluetooth, Wi-Fi ad hoc, Wi-Fi direct for example, may provide direct device-to-device connections in short radio range for basic P2P communications without awareness of services or applications at lower layers, such as the physical (PHY) layer or the medium access control (MAC) layer for example. 
     SUMMARY 
     Disclosed herein are a variety of systems, operations, MAC primitives, and methods for context-aware Peer-to-Peer (P2P) communications and multi-application Peer-to-Peer communications. Such communications may be performed at the physical (PHY) layer and/or the medium access control (MAC) layer, for example. 
     In one aspect, an example context-aware Peer-to-Peer communications system includes a physical and Medium Access Control (PHY/MAC) layer and an upper layer above the PHY/MAC layer. The PHY/MAC layer may include at least one of a discovery function, an association function, a data transceiving function, a channel management function, a general scan function, a synchronization function, a power control function, and/or measurement and report function. The upper layer may be one of a service layer or an application layer. The context management function can manage context information such that context information can be exchange between the upper layers and the PHY/MAC layer. 
     In another aspect, a system may comprise a plurality of peers in proximity with each other. An upper layer of a first peer of the plurality of peers may trigger a peer-to-peer (P2P) session with a second peer of the plurality of peers. The P2P session may use a first application. Further, the upper layer may download context information that is related to the first application such that the context information is available, via the context management function, to at least one of a discovery function of the first peer, an association function of the first peer, a data transceiving function of the first peer, a channel management function of the first peer, a general scan function of the first peer, a synchronization function of the first peer, a power control function of the first peer, or a measurement and report function. In yet another aspect, the P2P session may be a first P2P session, and the upper layer may trigger a second peer-to-peer (P2P) session with a third peer of the plurality of peers such that the first P2P session and the second P2P session overlap in time. The second P2P session may use a second application that is different than the first application. Further, the upper layer may download context information related to the second application such that the context information is available, via the context management function, to at least one of the discovery function of the first peer, the association function of the first peer, the data transceiving function of the first peer, the channel management function of the first peer, the general scan function of the first peer, the synchronization function of the first peer, the power control function of the first peer, or a measurement and report function. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to limitations that solve any or all disadvantages noted in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a system diagram of an example communication system in which multiple peer-to-peer (P2P) networks coexist in proximity with each other; 
         FIG. 2  depicts an exemplary system architecture for context-aware P2P communications. 
         FIG. 3  depicts an exemplary State Machine of a P2P System. 
         FIG. 4  depicts exemplary interfaces between a medium access control (MAC) layer and higher layers. 
         FIG. 5  illustrates an exemplary call for an P2P session initiation between two peers. 
         FIGS. 6 and 7  depict example association operations that include an idle and sleep mode for an example application. 
         FIGS. 8 and 9  illustrate exemplary multi-application data transmitting and receiving. 
         FIG. 10A  is a system diagram of an example machine-to-machine (M2M) or Internet of Things (IoT) communication system in which one or more disclosed embodiments may be implemented; 
         FIG. 10B  is a system diagram of an example architecture that may be used within the M2M/IoT communications system illustrated in  FIG. 10A ; 
         FIG. 10C  is a system diagram of an example M2M/IoT terminal or gateway device that may be used within the communications system illustrated in  FIG. 10A ; and 
         FIG. 10D  is a block diagram of an example computing system in which aspects of the communication system of  FIG. 10A  may be embodied. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Terminology 
     As used herein, the term “context” or the terms “context information” may generally refer to information that can be used to describe, track, and/or infer the situational state or condition of a service, an application, a device, a network, or a combination thereof. For example, context may refer to a service, an application, a location, a time, a power state, or the like. Examples of context information further include, presented by way of example and without limitation, location information, time information, an application category, a service power category, any user information, multi-hop information, mobility information, channel condition information, association information, device information, other application or service information, or the like. 
     A “peer”, as used herein, may refer to a user, device, or machine, such as, for example, a mobile station (MS) in a 2G system, a full-function device (FFD) or reduced-function device (RFD) in a IEEE 802.15 wireless personal area network (WPAN), a station (STA) in an IEEE 802.11 wireless system, or the like. Examples of peers that can participate in peer-to-peer communications (P2P) include connected cars, medical devices, smart meters, smart phones, tablets, laptops, game consoles, set-top boxes, cameras, printers, sensors, home gateways, music players, personal digital assistances, monitors, alarms, set-top boxes, Google glasses, drones, and service robots, among other things. A peer can be a group of users, devices, gateways, or machines sharing a group identity (ID). Peer-to-Peer (P2P) communication may refer to infrastructure based (e.g., centralized) or infrastructure-less (e.g., distributed) communications among peers within proximity of each other. 
     As also used herein, the term “peer discovery” refers to a procedure used for a peer to find another peer(s) before peer association or attachment to enable P2P communication in proximity. This procedure is sometimes also referred to as neighbor discovery (ND). 
     “Peer association” refers to a procedure used for a peer to establish a logic connection with another peer(s) before peer data transmission for P2P communication. This procedure may also be referred to as peer attachment, pairing, peering, link establishment, and the like. The term “peer association update” refers to a procedure used for a peer to update an Association Identifier and/or Association Context of an existing association relationship with other peer(s). “Peer disassociation” refers to a procedure(s) used for a peer to cancel an existing association relationship with other peer(s). “Peer re-association” refers to procedure(s) used for a peer to re-associate a cancelled association relationship with other peer(s). 
     Proximity services may refer to any service that can be provided to a device that is within a proximity. Thus, proximity services may be based on P2P communications in proximity. Proximity services may include human-to-human (H2H) proximity services, machine-to-machine (M2M) proximity services, machine-to-human (M2H) proximity services, human-to-machine (H2M) proximity services, and network to network proximity services. 
     H2H proximity services may refer to P2P communications that are user-based. Examples of H2H proximity services include various social networking implementations (e.g., status updates), gaming, streaming, content exchanging, conference meeting, eHealth, car pooling, emergency alarming, police or public safety services, etc. M2M proximity services may refer to device or object-based P2P communications. Example implementations of M2M proximity services include smart home or office implementations (e.g., auto configuration, synchronization, update, etc.), sensor networks, smart grids, or the like. M2H proximity services may refer to device (object) to human P2P communications. Example implementations of M2H proximity services include commercial broadcasts, group-casts, unicasts (e.g., personalized advertising), health monitoring implementations, health assistance implementations, hazard warnings, security monitoring implementations, traffic updates (e.g., congestion updates, accident updates, etc.), or the like. H2M proximity services human to device (object) based P2P communications. Example implementations of H2M proximity services include event scheduling, ticket updates, service reservations, smart parking, smart shopping, or the like. Example implementations of network to network proximity services may include, for example, multi-hop to infrastructure, offloading from infrastructure, uploading to hot spot, or the like. It will be understood that, unless otherwise stated, P2P communications may refer to P2P communications among a pair of peers or P2P communications among a group of peers, without limitation. 
     P2P Systems 
     As described above, current wireless systems, such as Bluetooth, Wi-Fi ad hoc, and Wi-Fi direct for example, may provide direct device-to-device connections in short radio range for basic P2P communications without awareness of services or applications at lower layers, such as the physical (PHY) layer or the medium access control (MAC) layer for example. By way of example of a current system, Device A might discover Device B, C, and D in proximity, but Device A might not be able to identify, which services or applications that the detected devices (B, C, or D) would like to join without going through a protocol stack up and down between the PHY/MAC layer and the application layers. Furthermore, current P2P systems do not fully support multiple services or applications simultaneously. 
       FIG. 1  illustrates an example communication system  100  in which one or more peer-to-peer networks (P2PNWs) may coexist in proximity. In the example system  100 , there are four P2PNWs  102 ,  104 ,  106 , and  108 , though it will be understood that any number of P2P networks may be implemented within a communication system as desired. Each P2PNW  102 ,  104 ,  106 ,  108  implements a respective P2P service or application, such as an advertisement application (e.g., Application  1 , where Peer 1  multi-casts or broadcasts commercial advertisements directly to Peer  2 , Peer 3 , Peer 4 , Peer 5  and Peer 6  in its radio range and where Peer 3  and Peer 5  multi-hop the commercial advertisement to Peer 3 - 1 , Peer 3 - 2 , Peer 5 - 1 , Peer 5 - 2  and Peer 5 - 3 , respectively), a chat application (e.g., Application  2  between Peer 6  and Peer 7  while Peer 6  also participates in Application  1  (Advertisement)), a keep alive application (e.g., Application  3  between Peer 5 - 3  and Peer  9  while Peer 5 - 3  also participates in Application  1  (Advertisement) and Peer 9  in Application  4  (game)), or a game application (e.g., Application  4 , where Peer 8 , Peer 9 , Peer 10 , Peer 11  and Peer 12  communicate to each other via unicast, multi-cast, or broadcast during the gaming session). A peer may be a tablet, smart phone, music player, game console, personal digital assistant, laptop, PC, medical device, connected car, smart meter, home gateway, monitor, alarm, sensor, set-top box, printer, a mobile station (MS) in a 2G network, a user equipment (UE) in a 3G network, or one or a group of full-function devices (FFDs) or reduced-function devices (RFDs) in IEEE 802.15 (wireless personal area network (WPAN)) networks. As one example, a peer may have the hardware architecture illustrated in  FIG. 10C  (described more fully below) or a variation thereof, or it may have the architecture of the computing system illustrated in  FIG. 10D  (also described more fully below). 
     In accordance with the illustrated example, the P2PNW  108  implements a distributed control scheme, wherein each peer of the P2PNW  108  manages control related communications with other peers of P2PNWs in proximity, by communicating with the other peers on a Common Control/Data Channel (CCDCH). The CCDCH may be used for, but not limited to, the following: common control messages among the P2PNWs in proximity, paging or broadcast messages to the P2PNWs in proximity, and short high priority data broadcasted to the P2PNWs in proximity. With distributed intra-P2PNW control, a peer manages its control related communications by communicating with other peers within a P2PNW, as shown by the solid or dotted, double-arrow lines. There is no VL acting as a central “controller”, nor any SubVL either. 
     In accordance with the illustrated example, the P2PNW  102  implements a centralized control scheme. In an example centralized intra-P2PNW control scheme, a VL manages all control related communications directly or through SubVL(s) within a P2PNW, via communications with other peers within the P2PNW on a Dedicated Control/Data Channel (DCDCH). For example, Peer 1  of the P2PNW  102  handles all control signals and/or messages among the peers (e.g., Peers  2 ,  4 ,  6 ) and SubVLs (e.g., Peers  3  and  5 ) within App 1  in the P2PNW  102 . Peer 3  is a SubVL for Peers 3 - 1  and  3 - 2 . 
     Referring now to  FIG. 2 , an example system architecture  200  may be included in a communication system, such as the system  100  shown in  FIG. 1 , for context-aware P2P communications. The architecture  200  may include a variety of structural entities and/or logic functions, such as a higher layer  202 , discovery function  204 , an association function  206 , a data transceiving function  208 , a channel management function  210 , a general scan function  212 , a synchronization function  214 , a power control function  216 , a measurement and reporting function  218 , and a context management function  220 . The functions  202 - 220  may be implemented by hardware and/or software in P2PNWs, such as the P2PNWs  102 ,  104 ,  106 , and  108  depicted in  FIG. 1  for example. 
     Still referring to  FIG. 2 , in accordance with illustrated embodiment, the higher layer  202  may be a layer above a physical (PHY) layer and medium access control layer in a protocol stack. As shown, the PHY layer and the MAC layer may be referred to collectively as a PHY/MAC layer  222 . Thus, the higher layer  202  may refer to a service layer or an application layer in an infrastructure-less P2P wireless system. As further described below, the context management function  220  may manage context information across the PHY/MAC layer  222  and the higher layer  202  for context-aware P2P communications. The general scan function  212  may scan a beacon, preamble, a paging channel, a broadcasting channel, or the like for various information such as a context category, a context identifier (ID), context information, or the like. The general scan function may extract scanned information for the synchronization function  214 , the peer discovery function  204 , the channel management function  210 , the power control function  216 , the measurement and report function  218 , and/or other functions. 
     Still referring to  FIG. 2 , in accordance with an example embodiment, the synchronization function  214  performs context-aware time synchronization with superframes, frames, and/or time slots. The context-aware time synchronization may refer to an initial or first synchronization or the context aware time synchronization may refer to a periodic time synchronization. In one embodiment, the synchronization function  214  may maintain frequency and/or phase synchronization. The discovery function  204  may discover peer(s) in proximity by using context category, context ID, and/or peer context information. The discovery function  204  may send messages with context category, context ID, and/or peer context information for to-be-discovered peers in proximity, as further described below. The association function  206  may request or respond to association messages, association updates, disassociation messages, or re-association messages by using context ID and/or peer context information. The channel management function  220  manages the radio resource or channel allocation among P2P networks based on context (e.g., services, applications). The channel management function  220  may further manage channel access within a P2P network based on peer context information. As further described below, the power control function may control transmit power control and manage interference, for example, based on context information and power control information. The data transceiving function  208  transmits and receives data in a context aware manner, for example, based on the quality of service (QoS) that is required by a service or application. The measurement and report function  218  may measure parameters associated with a channel, such as a QoS for example. The measurement and report function  218  may further send data reports associated with various functions, for instance the functions  204 - 216 , to the higher layer  202 , as further described below. 
     As illustrated in  FIG. 2 , parameters and context may be exchanged between the higher layer  202  and the functions  204 - 220 . Reports from the measurement and report function  218  may be fed back to the higher layer  202 . Certain logic functions in the PHY/MAC layer  222  may be triggered by the higher layer  202  and/or one or more other functions in the PHY/MAC layer  222 . In an example embodiment, power control can be applied to, as least some, for instance all, transmissions. At least because the various functions within the architecture  200  may exchange context information with each other and with the higher layer  202 , the example architecture  200  may also be referred to as a context-aware system architecture  200 . Example interactions between the higher layer  202  and the various illustrated functions at the PHY/MAC layer  222 , and example interactions between the illustrated logic functions with one another, are further described now. 
     With continuing reference to  FIG. 2 , in accordance with the illustrated embodiment, the higher layer  202 , which may also be referred to as an upper layer  202 , is the layer above the MAC layer in a layered structure for networking. For infrastructure-less P2P communications in proximity, in accordance with the illustrated embodiment, the higher layer  202  is a service or application layer. Triggers, which may include requests, and response messages may be exchanged between the higher layer  202  and the illustrated logic functions that reside at layers (e.g., PHY/MAC  222 ) are depicted in  FIG. 2 . The requests/responses, may enables direct interactions across layers for cross layer optimization. MAC primitives are described below that may be used to support messaging between the higher layer  202  and the illustrated functions, and such messaging may generally be referred to as cross layer interactions. 
     P2P communications may be initiated based on a desired service or application. Thus, P2P communications may be context driven. In the context-aware system architecture  200 , the context is managed and exchanged across layers by the context information management function  220 , which may be referred to as a cross-layer function, and the context is distributed to the illustrated functions at the PHY/MAC  222  as needed. For example, a first peer may be discovered by a second peer and associated with the second peer based on context. Table 1 shows examples of context information, presented by way of example and not presented by way of limitation, that may be used by various functions within the example context-aware architecture  200 . 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Example Context 
                 Example Functions 
               
               
                   
               
             
            
               
                 Context Category (e.g., emergency, 
                 General Scan, Discovery, 
               
               
                 social networking, smart office, etc.) 
                 Synchronization, 
               
               
                   
                 Association, etc. 
               
               
                 Context ID (e.g., Facebook, Netflix, 
                 General Scan, Discovery, 
               
               
                 GoToMeeting, etc.) 
                 Synchronization, etc. 
               
               
                 User/Device Info (e.g., user/device 
                 Discovery, Synchronization, 
               
               
                 ID, user/device profile, etc.) 
                 Association, Power 
               
               
                   
                 Control, etc. 
               
               
                 Service/Application Info (e.g., QoS 
                 Channel Management, 
               
               
                 requirements, required minimum 
                 Discovery, Association, etc. 
               
               
                 peers for gaming, multi-hop for 
               
               
                 extending the service range, etc.) 
               
               
                 Power Control Info (e.g., Power 
                 General Scan, Power Control, 
               
               
                 Category, Max./Min. Power, Power 
                 Measurements, etc. 
               
               
                 Control Interval, etc.) 
               
               
                 QoS Info (e.g., data rate, latency, 
                 Channel Management, Power 
               
               
                 priority, etc.) 
                 Control, Data Transceiving, 
               
               
                   
                 Measurements, etc. 
               
               
                 Others (e.g., location, speed, 
                 General Scan, Channel 
               
               
                 channel, etc.) 
                 Management, Discovery, 
               
               
                   
                 Synchronization, Association, 
               
               
                   
                 Power Control, 
               
               
                   
                 Measurements, etc. 
               
               
                   
               
            
           
         
       
     
     In some cases, a peer can participate in multiple services or applications simultaneously. The context-aware architecture  200  enables the various functions to support multiple applications based on the context information that is exchanged. For example, different power control schemes may be used for different services or applications, and the power control schemes may be based on power control context as shown in Table 1. 
     The general scan function  212  may scan a beacon, preamble, a paging channel, a broadcasting channel, or the like for various information such as a context category, a context identifier (ID), context information, or the like. The general scan function may extract scanned information for the synchronization function  214 , the peer discovery function  204 , the channel management function  210 , the power control function  216 , the measurement and report function  218 , and/or other functions. The general scan function  212  may be triggered or requested by the higher layer  202 , the synchronization function  214 , the discovery function  204 , the channel management function  210 , the power control function  216 , or the measurement function  218 . By way of example, in response to a request or trigger, the general scan function  212  may extract and provide detected results, such as available radio channels, signal strength, extracted context information, or the like for example, to the higher layer  202 . The general scan function  212  may extract fields for the synchronization function  214 . Such fields may include a synchronization bit pattern, a time stamp, a frame location, a slot size, or the like. The general scan function  212  may extract information for the discovery function  204 . Such information may include an context ID, such as a service ID, an application ID, a user ID, a device ID, or the like. By way of further example, extracted information for the discovery function  204  may include other context information, such as a detected signal strength, used in discovery. The general scan function  212  may extract information for the channel management function  210 , such as, for example, channel allocation information and channel usage information that is broadcast in proximity. The general scan function  212  may extract information for the power control function  216  such as, for example, a transmitting power level and related power control information in proximity. The general scan function  212  may detect signals in proximity used for measurements, and the general scan function  212  may provide such information to the measurement and report function  218 . 
     The synchronization function  214  may perform context-aware time synchronization with superframes, frames, and/or time slots. The context-aware time synchronization may refer to an initial or first synchronization, or the context aware time synchronization may refer to a periodic time synchronization. In one embodiment, the synchronization function  214  may maintain frequency and/or phase synchronization. 
     The synchronization function  214  may be triggered by, for example receive requests from, the higher layer  202 , the general scan function  212 , the discovery function  204 , the association function  206 , the data transceiving function  208 , and the channel management function  210 . The synchronization function  214  may respond to a trigger or request with various synchronization information or results. For example, the synchronization function  214  may send synchronization information to the higher layer  202  after recovering from a power saving mode, a sleep state, a system timing reset, or the like, which may be triggered by the higher layer  202 . The synchronization function  214  may provide results (e.g., success or fail) to the general scan function  212  that indicate whether a synchronization was successful. For example, a successful synchronization may enable the general scan function  212  to extract fields that may be required by the discovery function  204 , the channel management function  210 , or the power control function  216 . The discovery function  210  may receive results of a successful synchronization so that the discovery function  210  may to send or broadcast a “to be discovered” message via a common or a designated channel assigned by the channel management function  210 . The association function  206  may receive results of a successful synchronization so that the association function  206  may proceed with an association, an association update, a re-association, or the like. The data transceiving function  208  may receive results of a successful synchronization so that the data transceiving function  208 , for example, re-alignment with a time reference or boundary, correct a frequency and/or phase offset required by for data transceiving, or the like. The channel management function  210  may receive results of a successful synchronization so that the channel management function  210  may deliver appropriate channel requests and responses. 
     Still referring to  FIG. 2 , the discovery function  204  may discover peer(s) in proximity by using context category, context ID, and/or peer context information. The discovery function  204  may send messages with context category, context ID, and/or peer context information for to-be-discovered peers in proximity. The discovery function  204  may be triggered by, for example receive requests from, the higher layer  202  and the association function  206 . The discovery function  204  may send responses to the higher layer  202  that include peer discovery results and related information. The discovery function  204  may send responses to the association function  206  that indicate peer candidates that have been discovered and related information for associating or re-associating peers. 
     In accordance with the illustrated embodiment, the association function  206  may be triggered by, for example receive requests from, the higher layer  202 , discovery function  204 , the synchronization function  214 , and the data transceiving function  208 . The association function  206  may send responses to the higher layer  202  that include peer association results and information related to peer association. The association function  206  may send a result that indicates a successful association to the discovery function  204  such that a discovery is stopped. Alternatively, the association function  206  may send a result that indicates a failed association to the discovery function  204  such that the association function  206  requests that the discovery function  204  find new peer candidates. The higher layer  202  may request that the association function  206  disassociate with a peer, for example, due to a channel condition or a QoS condition. By way of another example, the synchronization function  214  may request that the association function  206  disassociate with a peer, for example, due to a failed synchronization. By way of yet another example, the data transceiving function  208  may request that the association function  206  disassociate with a peer, for example, due to a failed data transfer. The association function  206  may respond to a disassociation request with a response that indicates that the disassociation was successful. Similarly, the higher layer  202  may request that the association function  206  perform a re-association, for example, after a peer returns from a power saving or sleep mode, or due to a channel condition. By way of example, the data transceiving function  208  may request that the association function  206  perform a re-association due to a QoS associated with received and/or transmitted data. 
     In accordance with the illustrated embodiment, the channel management function  210  may be triggered by, for example receive requests from, the higher layer  202 , the discovery function  204 , and the association function  206 . The channel management function  210  may send responses to the higher layer  202  that include, for example, channel allocation information, channel usage information, channel measurements, QoS statuses, or the like. The channel management function  210  may send responses to the discovery function  204  that includes, for example, a channel allocation for broadcasting a message, such as a “to be discovered message” for example. The channel management function  210  may send responses to the association function  206  that includes, for example, a new channel allocation, usage information for association and/or re-association, a channel de-allocation, or the like. 
     The power control function  216  may perform transmitting power control and interference management during discovery, association, channel management, and data transceiving procedures. For example, the power control function  216  may estimate power for various transmissions. In accordance with the illustrated embodiment, the data transceiving function  208  may be triggered by, for example receive requests from, the higher layer  202 . The data transceiving function  208  response with a success message, which may be an acknowledgement (ACK) message, or a failures message, which may be a negative acknowledgement (NACK) message. MAC primitives are described herein for supporting the interactions between the higher layer  202  and data transceiving function  208 . 
     In accordance with the illustrated embodiment, the measurement and report function  218  conducts measurements requested by the higher layer  202 , such as measurements association with a channel condition, a QoS, of the like. The measurement and report function  218  may also send measured results from other functions to the higher layer  202 . The measurements and report function  218  may also be used to update context or generate new context that is shared among the functions and/or across layers by the context management function  220 . The measurement and report function  218  may collect measurements and/or reports from one or more, up to all, of the illustrated functions  204 - 220  in the example architecture  200 . 
     Referring also to Table 2 below, the measurement and report function  210  may be triggered by, for instance receive requests from, the higher layer  202 . The higher layer  202  may request various measurements and reports that are associated with various functions, such as those presented by way of example in Table 2. Examples of measurements and reports provided by the logic functions within the architecture  200  are shown in Table 2. 
     
       
         
           
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Example Measurements/Reports 
                 Example Functions 
               
               
                   
               
             
            
               
                 Channel condition (e.g., SINR, Received Signal 
                 Measurements, Power 
               
               
                 Strength, Channel Quality Indicator, etc.) 
                 Control, etc. 
               
               
                 QoS (i.e. data rate, error rate, etc.) 
                 Data Transceiving 
               
               
                 Channel status (e.g., allocation, usage, etc.) 
                 Channel Management, 
               
               
                   
                 etc. 
               
               
                 Synchronization results (e.g., success, failure, 
                 Synchronization 
               
               
                 time or frequency offset, etc.) 
               
               
                 Discovery results (e.g., peer candidates, P2P 
                 Discovery 
               
               
                 network(s) detected in proximity, etc.) 
               
               
                 Association results (e.g., association log, 
                 Association 
               
               
                 association successful rate, etc.) 
               
               
                 Power Control Info (e.g., Max./Min. transmitting 
                 Power Control 
               
               
                 power, averaged transmitting power, power 
               
               
                 adjustment, etc.) 
               
               
                   
               
            
           
         
       
     
       FIG. 3  shows an example state diagram  300  for P2P communications that can be implemented by the architecture  200 , such as one or more of the peers in the example system  100  for example. Referring to  FIG. 3 , an example P2P communication session may contain one or more operational states. As shown in  FIG. 3 , the operational states may include a “To Discover” state  302 , an association state  304 , an idle state  306 , a data transceiving state  308 , an association update state  310 , a sleep state  312 , a disassociation state  314 , a re-association state  316 , a channel management state  318 , and a “To Be Discovered” state  320 . 
     Referring also to  FIG. 2 , the higher layer  202  may send a trigger to the MAC/PHY layer  222  to start an application (depicted as application i in  FIG. 3 ). Based on the trigger, a peer, for example a first peer, may enter the “To Discover” state  302 . In the state  302 , in accordance with the illustrated embodiment, the first peer scans for the other peers in proximity with the first peer. The peers may be scanned for Application i. The scan may include searching for beacons, paging, and/or searching for broadcasting channels. If a peer is discovered for Application i, the first peer may transition to the association state  304  to establish a connection or to link with the discovered peer. In some cases, if the first peer does not find a peer in proximity for Application i within a predefined scan time interval, the first peer may transition to the “To Be Discovered” state  320 . In the “To Be Discovered State”  320 , the first peer may request to be discovered by another peer. While the first peer is in the “To Be Discovered” state  320 , the first peer may wait for an association request from a peer in proximity. By way of example, the first peer may request a designated channel to send the “To Be Discovered” message through the channel management state  318  for channel allocation. Alternatively, the first peer may send the “To Be Discovered” message on a known or predefined common, dedicated, or public channel, and thus may skip the channel management state  318  for channel allocation. 
     With continuing reference to  FIG. 3 , in accordance with the illustrated embodiment, the first peer may exit the “To Be Discovered” state  320 , and transition to the association state  304  if an association request is received from the higher layer or an air interface associated with the first peer. An association request associated with an air interface of the first peer may be an association request from a peer in proximity. Alternatively, the first peer may exit the “To Be Discovered” state  320 , and transition to the “To Discover” state  302 , for example, if the first peer receives a “To Discover” request from the higher layer  202  of the “To Be Discovered” state  320  times out. As mentioned above, when the first peer is in the channel management state  318 , the first peer may request a channel for transmitting a “To Be Discovered” message that indicates that the first peer wants to be discovered by another peer. 
     When the first peer is in the association state  304 , the first peer may send an association request or an association response to a peer that has been discovered, for example a peer that has been discovered for Application i. The association messages may be sent or received via the air interface. The first peer may request a designated channel to send the “association” message through the channel management state  318  for channel allocation. Alternatively, the first peer may send the “association” message on a known or predefined common, dedicated, or public channel, and thus may skip the channel management state  318  for channel allocation. Similarly, by way of example, the first peer may request a radio link or channel for P2P data transceiving while in the association through the channel management state  318 . Thus, the link or channel may be used as an intra-P2PNW channel while the first peer is in the data transceiving state  308 . Alternatively, the first peer may use a predefined radio link or channel during the data transceiving state  308 , and thus the first peer may skip the channel management state  318  for channel allocation. In accordance with the illustrated example, the first peer may exit the association state  304 , and transitions to the idle state  306  after a successful association. During the idle state  306 , the first peer may wait to transmit data or to receive a request. In an alternative example scenario, the first peer may exit the association state  304 , and transition to the “To Discover” state  302 , for example, to find a new peer in proximity for Application i. Such a transition may occur after an unsuccessful association. 
     As described above, during the channel management state  318 , the first peer may request channel allocation for transmitting an association message and/or to access an intra-P2PNW channel that can be used when the first peer is in the data transceiving state  308 . When the first peer is in the idle state  306 , the first peer may wait for a data request after a successful association, association update, re-association, or data transmission. The first peer may exit the idle state  306 , and transition to the data transceiving  308 , for example state after receiving a data transmission or signal from the higher layer  202 . The first peer may exit the idle state  306  and transitions periodically to the association update state  310 , for example, to maintain an association with a current peer while data is not being transmitted or received. In some cases, the first peer may exit the idle state  306  and transition to the sleep state  312  for saving power as a result of receiving a sleep command from the higher layer  202 . In other cases, the first peer may exit the idle state  306  and transition to the disassociation state  314  as a result of a Disassociation Request that is received from the higher layer or another peer via the air interface. The disassociation request may be based on a mobility associated with the first peer, a channel condition, or the like. 
     In accordance with the illustrated example, the first peer may enter the data transceiving state  308  from the idle state  306 . When the first peer is in the data transceiving state  308 , the first peer may transmit data or receive data from another peer via the air interface. When exiting the data transceiving state  308 , the first peer may transition to the idle state  306 , for example, after a successful data transmission or a successful data reception. Alternatively, the first peer may exit the data transceiving state  308  and transitions to the disassociation state  314 , for example, because of low QoS or because of a data reception or transmission failure. 
     Referring now to the association update state  310 , as shown, the first peer may enter the association update state  310  from the idle state  306  or the sleep state  312 . The first peer may update a current association with a peer, via the air interface, using an association update request and/or response. The first peer may exit the association update state  310  and transition to the idle state  306  state after a successful “Association Update” has been performed. Alternatively, the first peer may exit the association update state  310  and transition to the sleep state  312  after a successful “Association Update” has been performed based on a timed wake up from the sleep state  312 . Alternatively still, the first peer may exit the association update state  310  and transition to the re-association state  316  to establish a new link after an unsuccessful association update is performed with the current link. 
     Referring now in particular to the sleep state  312  depicted in the diagram  300 , the first peer may enter the sleep state  312  from the idle state  306 , for example, due to a predetermined time associated with the idle state  306  elapsing,), or due to a sleep command that is received from the higher layer  202 . Thus, the first peer may periodically enter the association update state  310  as defined by a wake up timer, or the first peer may enter the association update state as a result of the higher layer&#39;s “wake up” command. Similarly, the first peer may transition to the disassociation state  314  after a predefined time interval elapses without any data transceiving activity, or as a result of a disassociation command that is received from the higher layer  202 . 
     In accordance with the illustrated example, in the disassociation state  314 , the first peer may make a channel deallocation request such that link resources are released via the channel management state  318 . The first peer may enter the disassociation state  314  from the data transceiving state  308 , for example, in response to a low QoS or in response to a failed data transmission or reception. By way of further example, the first peer may enter the disassociation state  314  from the idle state  306  in response to a disassociation request from the higher layer  202  or a peer via the air interface. By way of yet another example, the first peer may enter the disassociation state  314  from the sleep state  312  in response to a predetermined time associated with a sleep mode expiring or in response to receive a disassociation request from the higher layer  202 . The first peer may exit the disassociation state  314 , and transition to the re-association state  316  in response to a “Resume” (re-association) command received from the higher layer  202 . Alternatively, the first peer may exit the disassociation state  314 , and transition to the “to Discover” state  302  in response to “Discover New Peer” command received from the higher layer  202 . Alternatively still, the first peer may exit the disassociation state  314 , and transition to the End state in which the application i ends, in response to an “End Application i” command received from the higher layer  202 . 
     Referring in particular to the re-association state  316 , the first peer may perform re-association with a peer via the air interface. The first peer may enter the re-association state  316  from the association update state  310 , for example, in response to a failure in updating a current link (the current association) between peers. The first peer may enter the re-association state  316  from the disassociation update state  314  in response to a “Resume” command received from the higher layer  202 . Re-association requests may sent over designated channels in which the first peer requests via the channel management state  318 . Alternatively, re-association messages may be sent over common or public channels, and thus the channel management state  318  (for channel allocation) may be skipped during re-association. The first peer may exit the re-association state  316  and transition to the idle state  306  after a successful re-association. In another example, the first peer may exit the re-association state and transition to the “To Discover” state  302  to find a new peer, for example, in response to an unsuccessful re-association with the current peer. During the ends state  322 , in accordance with the illustrated example, the first peer exits Application i after disassociation in response to an “End Application i” command received from the higher layer  202 . 
     Referring now to  FIG. 4 , an example protocol stack  400  includes the upper layers  402  (which may also be referred to as the higher layer  202 , without limitation), a MAC layer  404  that is below the upper layers  402  in the stack  400 , and a PHY layer  406  that is below the MAC layer  404  in the stack  400 . The higher layer  402  may include various applications, and thus may also be referred to as an application layer. As shown in  FIG. 4 , a MAC Layer Management Entity (MLME) Service Accessing Point (SAP)  408  and an MAC Common Part Sublayer (MCPS) SAP  410  interfaces between the MAC layer  404  and the upper layers  402 , where the MLME SAP  408  is for management and the MCPS SAP  410  is for data as specified in IEEE 802.15. 
     To support multiple applications in the upper layers  402 , several example context-aware, and in particular application-aware. MAC Primitives are described below. In accordance with various embodiments, example MAC MLME primitives are listed in Table 3 (below) for management messages that delivered through the MLME SAP  410  interface with the upper layer  402 . Further, an example MAC MCPS primitive is listed in Table 4 (below) for data messages that delivered through the MCPS SAP  408  interface with the upper layer  402 . The primitives presented in Table 3 and Table 4 are presented by way of example, and are not presented by way of limitation. 
     
       
         
           
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 MLME Example 
                   
                   
               
               
                 Primitives 
                 Type 
                 Description 
               
               
                   
               
             
            
               
                 MLME-CONTEXT-APPi 
                 Request, 
                 CONTEXT exchange for Application i 
               
               
                   
                 Confirm 
                 This may enables the context exchange with a 
               
               
                   
                   
                 higher layer for a specific application. 
               
               
                 MLME-GENSCAN 
                 Request, 
                 GENeral SCAN initiated by higher layer 
               
               
                   
                 Confirm 
                 This may enable the higher layer to trigger a 
               
               
                   
                   
                 general purpose scan with related context 
               
               
                   
                   
                 information. For example, a general scan can be 
               
               
                   
                   
                 used to detect the useful peer information in 
               
               
                   
                   
                 proximity needed by multiple logic functions, such 
               
               
                   
                   
                 as, for example, peer discovery, context-aware 
               
               
                   
                   
                 synchronization, channel allocation detection, 
               
               
                   
                   
                 context-aware power detection etc., which may be 
               
               
                   
                   
                 particularly useful at the beginning of establishing 
               
               
                   
                   
                 an infrastructure-less P2P network. 
               
               
                 MLME-START-APPi 
                 Request, 
                 START Application i 
               
               
                   
                 Confirm 
                 This may enable the higher layer to initiate a P2P 
               
               
                   
                   
                 network for a specific application. 
               
               
                 MLME-SYNC-APPi 
                 Request 
                 SYNChronization for Application i 
               
               
                   
                   
                 This may enable the higher layer to direct the 
               
               
                   
                   
                 Synchronization Function to synchronize with a 
               
               
                   
                   
                 specific application, which may be especially useful 
               
               
                   
                   
                 for supporting multiple applications simultaneously. 
               
               
                 MLME-SYNC-LOSS-APPi 
                 Indication 
                 SYNChronization LOSS for Application i 
               
               
                   
                   
                 This may enable the Synchronization Function to 
               
               
                   
                   
                 notice the higher layer the loss of synchronization 
               
               
                   
                   
                 for a specific application. 
               
               
                 MLME-DISCOVERY-APPi 
                 Request, 
                 DISCOVERY for Application i 
               
               
                   
                 Confirm, 
                 This may enable the higher layer to assist peer 
               
               
                   
                 Indication, 
                 discovery for a specific application. For example, 
               
               
                   
                 Response 
                 some confirmation may be needed from the user for 
               
               
                   
                   
                 security and/or privacy concerns. 
               
               
                 MLME-CHANNEL-APPi 
                 Request, 
                 CHANNEL management for Application i 
               
               
                   
                 Confirm 
                 This may enable the higher layer to trigger channel 
               
               
                   
                   
                 re-allocation due to channel conditions or QoS of 
               
               
                   
                   
                 the service for a specific application. 
               
               
                 MLME-ASSOCIATE-APPi 
                 Request, 
                 ASSOCIATE for Application i 
               
               
                   
                 Confirm 
                 This may enable the higher layer to assist peer 
               
               
                   
                 Indication, 
                 association for a specific application. For example, 
               
               
                   
                 Response 
                 some confirmation may be needed from the user for 
               
               
                   
                   
                 security and/or privacy concerns. 
               
               
                 MLME- 
                 Request, 
                 ASSOCIATE UPDATE for Application i 
               
               
                 ASSOCIATEUPDATE-APPi 
                 Confirm 
                 This may enable the higher layer to trigger 
               
               
                   
                 Indication, 
                 association update for a specific application. For 
               
               
                   
                 Response 
                 example, update the associate due to context 
               
               
                   
                   
                 change, or QoS, etc. 
               
               
                 MLME- 
                 Request, 
                 DISASSOCIATE for Application i 
               
               
                 DISASSOCIATE-APPi 
                 Confirm, 
                 This may enable the higher layer to trigger 
               
               
                   
                 Indication, 
                 disassociation for a specific application. For 
               
               
                   
                 Response 
                 example, disassociation due to channel status, 
               
               
                   
                   
                 QoS, or service policy, etc. 
               
               
                 MLME- 
                 Request, 
                 RE-ASSOCIATE for Application i 
               
               
                 REASSOCIATE-APPi 
                 Indication, 
                 This may enable the higher layer to trigger re- 
               
               
                   
                 Response, 
                 association for a specific application. For example, 
               
               
                   
                 Confirm 
                 re-associate due to channel condition, QoS, or 
               
               
                   
                   
                 policy, etc. 
               
               
                 MLME-TX-APPi 
                 Request, 
                 Enable TX (transmitting) for Application i 
               
               
                   
                 Confirm 
                 This may allow the higher layer to enable 
               
               
                   
                   
                 transmitting for a specific application. 
               
               
                 MLME-RX-APPi 
                 Request, 
                 Enable RX (receiving) for Application i 
               
               
                   
                 Confirm 
                 This may allow the higher layer to enable receiving 
               
               
                   
                   
                 for a specific application. 
               
               
                 MLME- 
                 Request, 
                 POWER CONTROL for Application i 
               
               
                 POWERCONTROL-APPi 
                 Confirm 
                 This may enable the higher layer to trigger the 
               
               
                   
                   
                 context-aware power control for a specific 
               
               
                   
                   
                 application. 
               
               
                 MLME-MEASURE-APPi 
                 Request, 
                 MEASUREment for Application i 
               
               
                   
                 Confirm 
                 This may enable the higher layer to trigger the 
               
               
                   
                   
                 measurement for a specific application, which may 
               
               
                   
                   
                 be used for cross-layer QoS management. 
               
               
                 MLME-REPORT-APPi 
                 Request, 
                 REPORT from logic functions for Application i 
               
               
                   
                 Confirm 
                 This may enable the higher layer to trigger the 
               
               
                   
                   
                 report function for a specific application, which may 
               
               
                   
                   
                 be used for cross-layer QoS management. 
               
               
                 MLME-SLEEP-APPi 
                 Request, 
                 SLEEP mode for Application i 
               
               
                   
                 Confirm, 
                 This may enable the higher layer to force lower 
               
               
                   
                 Indication, 
                 layers into sleep mode. 
               
               
                   
                 Response 
               
               
                 MLME-WAKEDUP-APPi 
                 Request, 
                 WAKE UP from sleep mode for Application i 
               
               
                   
                 Confirm 
                 This may enable the higher layer to pull lower layers 
               
               
                   
                   
                 out of sleep mode. 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                 MCPS 
                   
                   
               
               
                 Primitives 
                 Type 
                 Description 
               
               
                   
               
             
            
               
                 MCPS-DATA- 
                 Request, 
                 DATA transmission for Application i 
               
               
                 APPi 
                 Indication, 
                 This may enable the higher layer to trigger 
               
               
                   
                 Confirm 
                 the Data Transceiving Function to transmit 
               
               
                   
                   
                 data for a specific application, which may 
               
               
                   
                   
                 be needed for supporting multi-application 
               
               
                   
                   
                 data transmitting and receiving. 
               
               
                   
               
            
           
         
       
     
     Referring generally to  FIG. 2  and particularly to  FIG. 5 , an example system  500 , which includes at least a portion of the architecture  200 , initiates P2P communication in a context-aware manner in accordance with an example embodiment. The system  500  includes a plurality of peers, for example a first peer  502  and a second peer  504 . It will be appreciated that the example system  500  is simplified to facilitate description of the disclosed subject matter and is not intended to limit the scope of this disclosure. Other devices, systems, and configurations may be used to implement the embodiments disclosed herein in addition to, or instead of, a system such as the system  500 , and all such embodiments are contemplated as within the scope of the present disclosure. 
     Still referring to  FIG. 5 , in accordance with the illustrated embodiment, a P2P communication in proximity is established based on the a desired service or application, and thus P2P communication in proximity is based on a desired context. The procedure may contain the following steps for setting up a P2P communication in proximity. The above-listed context-aware IEEE 802.15.8 MAC Primitives are used in the example embodiment shown in  FIG. 5  so that the peers can interface with a higher layer, such as the higher layer  202 , which may also be referred to as the upper layer  202 . As one example, the peer  502  and  504  may have the configuration illustrated in  FIG. 10C  (described more fully below) or a variation thereof. The peers  502  and  504  may further have the architecture  200  illustrated in  FIG. 2 . For example, as illustrated, the first peer  502  includes a first upper layer  202   a  and a first PHY/MAC layer  222   a  that includes a first discovery function  204   a , a first channel management function  210   a , and a first association function  206   a . Further, as illustrated, the second peer  504  includes a second upper layer  202   b  and a second PHY/MAC layer  222   b  that includes a second discovery function  204   b , a second association function  206   b , a second synchronization function  214   b , and a second general scan function  210   b . It will be understood that the peers  502  and  504  may include other functions in addition to the functions that are illustrated, such as those functions that are described with reference to  FIG. 2  for example, as desired. 
     At  506 , in accordance with the illustrated embodiment, the first peer  502  wants to start a P2P session in proximity with an application depicted for purposes of example in  FIG. 5  as Application  1 . At  506 , the first upper layer  202   a  sends the first peer  502  an MLME-START-APP Lrequest to trigger the first discovery function  204   a . At  508 , the first upper layer  202   a  downloads context related to Application) to at least some functions, for instance all functions, via the first context management function  210   a . At  510 , the first peer  502  makes a channel allocation request. In particular, at  510 , the first discovery function  204   a  sends a request to the first channel management function  201  for a radio resource to be used for broadcasting or sending a “to be discovered” message in proximity. At  512 , the first channel management function  210   a  finds the radio resource or channel in proximity for Application). At  514 , in accordance with the illustrated example, the first channel management function  210   a  responds back to the first discovery function  204   a  with channel allocation information. At  516 , the first discovery function  204   a  broadcasts or sends a “to be discovered” message over the assigned channel, and waits for the response to the discovery request from a peer or peers in the proximity, such as the second peer  504  for example. At  518 , the first discovery function  204   a  responds to the first upper Layer  202   a  with a MLME-START-APP1.confirm message. 
     Still referring to  FIG. 5 , at  520 , which may after some time after the first upper layer  202  receives the confirmation message from 518, the second upper layer  202   b  of the second peer  504  sends a discovery trigger or request (e.g., MLME-DISCOVERY-APP1.request) to the second discovery function  204   b , for example, because the second peer  504  may want to discover one or more peers for Application  1  in proximity. At  522 , the second upper layer  202   b  downloads context related to Application 1  to logic functions of the second peer  504  via the context management function  210  of the second peer  504 . At  524 , the second discovery function  204   b  sends a trigger or request to the second general scan function  210 B for Application). At  526 , in accordance with the illustrated embodiment, the second general scan function  210 B scans for Application 1 , for example, by scanning Beacons, preambles, paging and/or broadcast messages for peer discovery with context information related to Application 1 , such as Context Category and/or Context ID for example. At  528 , the second general scan function  210 B sends a synchronization trigger or request to the second synchronization function  214   b  with the synchronization information that was detected. At  530 , the second synchronization function  214   b  performs context-aware synchronization with context information related to Application 1 . At  532 , the second synchronization function  214   b  sends the synchronization response to the second general scan function  210 B. At  534 , the second general scan function  210 B responds to the scan request from the second discovery function  204   b  with the extracted information for discovery. At  536 , the second discovery function  204  discovers the first peer  502  for Application 1  using context information associated with Application 1 , such as Context Category, Context ID, peer information, or the like. At  538 , the second discovery function  204   b  responds to the second upper layer  202   b  with a confirmation message (e.g., MLME-DISCOVERY-APP 1 .confirm), and thus exits the discovery state. 
     With continuing reference to  FIG. 5 , at  540 , the second upper layer  202   b  sends a trigger or request to the second association function  206   b  with an MLME-ASSOCIATION-APP Lrequest, for example, after validating the discovery confirmation from the second discovery function  204   b . At  542 , the second association function  206   b  sends an association request to the first peer  502 , over the air. The association request includes related context-aware association information. The first association function  206   a  receives the request. At  544 , the first association function  206   a  notifies the first upper layer  202   a  with an MLME-ASSOCIATION-APP 1 .indication and related context-aware association information. At  546 , in accordance with the illustrated example, the first upper layer  202   a  responds to the first association function  206   a  with an MLME-ASSOCIATION-APP 1 .response, after validating the association of the first peer  502  and the second peer  504 . At  548 , the first association function  206   a  responds back to the second peer  504  via the air interface. The second association function  206   b  notifies the second upper layer  202   b  a confirmation message (MLME-ASSOCIATION-APP 1 .confirm). Thus, at  552 , the first and second peers  502  and  504  may enter the P2P session with each other for Application 1 . 
     In some cases in which applications have small and infrequent data transmissions or receptions, referred to herein as data transceivings, there may be long time intervals during which a P2P system does not transceive any data. A “keep alive” application for social networking is an example application that may have small or infrequent data transceivings. In such cases, in accordance with an example embodiment, power can be saved and interference in proximity can be limited by allowing peer devices to enter a sleep mode in which at least some of the radio units and data processing units of the peer devices are turned off  FIGS. 6 and 7  depict example association operations associated with idle and sleep states, as described above. 
     Referring to  FIGS. 6 and 7 , the example system  500  includes the first peer device  502 , which further includes a first data transceiving function  208   a . As illustrated in  FIGS. 6 and 7 , the second peer device  504  further includes a second data transceiving function  208   b  and a second context management function  210   b . Referring in particular to  FIG. 6 , in accordance with the illustrated example, at  600   a , the first and second peers  502  and  504  have established a P2P session with each other associated with an application, referred to for purposes of example as Application  1 . Further, at  600   c , the first and second peers  502  and  504  are in the idle state  306  after transmitting and receiving data between each other, at  600   b . An association update may be initiated when a predefined Association Update timer expires or when an Association Update Request is received by the first association function  206   a  from the first upper layer  202   a , at  602 . At  604 , in accordance with the illustrated example, the first peer  502  sends an Association Update request to the second peer  504  over the air (via an air interface). At  606 , the second Association Function  206   b  of the second peer  504  indicates to the second Higher Layer  202   b  that an Association Update request has been received. At  608 , the second Higher Layer  202   b  returns an Association Function Response to the second Association Function  206   b , where the Association Function Response acknowledges the Association Update request. At  610 , the second peer  504  sends an Association Update response to the first peer  502  via the Air Interface to acknowledge the Association Update. At  612 , the Association Function  206   a  confirms to the first Higher  202   a  Layer that the Association Update is successful. At  614 , the first and second peer  502  and  504  return to the idle state  306 . It will be understood, as described above, that the peers  502  and  504  may repeat the cycle of transitioning between the idle state  306  and the association update state  310  without actively exchanging data. 
     Still referring to  FIG. 6 , at  616 , the first higher layer  202   a  sends a sleep request to the data transceiver function  208   a . Alternatively, the sleep state  312  may be initiated by a predefined Idle monitoring timer expiring. In accordance with the illustrated example, at  618 , the first peer  502  sends a Sleep request to the second peer  504  via the Air Interface. At  620 , the second higher layer  202   b  is notified, by the second data transceiver function  208   b , that the Sleep request is received. At  622 , the second higher layer returns a Sleep Response to acknowledge the sleep request. At  624 , the second peer  504  sends a Sleep response to the first peer  502  via the Air Interface to acknowledge the Sleep request. At  626 , in accordance with the illustrated example, the first Higher Layer  202   a  receives confirmation of the Sleep request. At  628 , the first and second peers  502  and  504  set their sleep timers according to the request and enter into the sleep state  312 . At  630 , the sleep timers expire and the first and second peer  502  and  504  wake. At  632 , the first and second peers  502  and  504  perform an Association Update as described above with respect to steps  602 - 612 . At  624 , the first and second peers  502  and  504  return to the sleep state  512 . It will be understood, as described above, that the peers  502  and  504  may repeat the cycle of transitioning between the sleep state  312  and the association update state  310  without actively exchanging data. 
     With continuing reference to  FIG. 6 , in accordance with the illustrated example, at  636 , the first upper layer  202   a  sends a Disassociation Request to the first association function  206   a . Alternatively, a disassociation may be initiated by a predefined sleep monitoring timer when a sleep time expires. At  638 , the first peer  502  sends a Disassociation request to the second peer  504  via the Air Interface. At  640 , the association function  206   b  indicates to the second Higher Layer  202   b  that a Disassociation request is received. At  642 , the second higher layer  202   b  returns a Disassociation Response to the second Association Function  202   b , wherein the disassociation response acknowledges the Disassociation request. At  644 , the second peer  504  sends a Disassociation response to the first peer  502  via the Air Interface to acknowledge the Disassociation. As shown, at  646   a , the second peer&#39;s Disassociation response may be received at the first peer  502 , thereby indicating a graceful Disassociation. Alternatively, as shown at  646   b , the second peer&#39;s Disassociation response might not be received by the first peer  502 , for example due channel problems, thereby resulting in a non-graceful Disassociation. Either way, at  648 , the first Association Function  206   a  may confirm to the first Higher Layer  202   a  that the Disassociation is enforced with or without receiving the response from the second peer  504 . 
     Referring now to  FIG. 7 , in accordance with the illustrated embodiment, at  650 , the Association Function  206   a  sends a Channel De-allocation request to the first Channel Management Function  210   a  to release a resource (channel). At  652 , the first Channel Management Function  210   a  releases the channel. The first and second peers  502  and  504  may stay disassociated for some time. At  654 , a Re-association is initiated by the Higher Layer  202   a . At  656 , the first Association Function  206   a  sends a Channel Allocation request to the Channel Management Function  210   a  for the radio resource (channel). At  658 , the first Channel Management Function  210   a  confirms the Channel Allocation. At  660 , the first peer  502  sends a Re-association request to the second peer  504  via the Air Interface. 
     In one embodiment, at  662 , the second association function  206   b  indicates to the second Higher Layer  202   b  that the Re-association request is received. Thus, at  664 , the second higher layer  202   b  returns a Re-association Response to the second Association Function  206   b  that acknowledges the Re-association request. At  666 , the second peer  504  sends a Re-association response to the first peer  502  via the Air Interface to acknowledge the Re-association. At  668 , as shown, the first Association Function  206   a  confirms to the first Higher Layer  202   a  that the Re-association is successful. Thus, at  670 , the first peer  502  and the second peer enter the idle state  306 , and are ready for data transceiving. 
     In another example, at  671 , the second peer  504  does not the re-association request from the first peer  502 , or example, because the second peer moves away from the first peer  502 , as shown at  671 . Thus, at  672 , the re-association may be timed out. At  674 , in accordance with the illustrated example, the first Association Function  206   a  confirms to the first Higher Layer  202   a  that the Re-association has failed. Thus, at  676 , the first peer may enter the “To Discover” state  302  to find a new peer in proximity. 
     Referring now to  FIGS. 8 and 9 , an example system  800 , which includes at least a portion of the architecture  200 , includes a plurality of peers, for example the first peer  502 , the second peer  504 , and a third peer  505 . It will be appreciated that the example system  800  is simplified to facilitate description of the disclosed subject matter and is not intended to limit the scope of this disclosure. Other devices, systems, and configurations may be used to implement the embodiments disclosed herein in addition to, or instead of, a system such as the system  800 , and all such embodiments are contemplated as within the scope of the present disclosure. The third peer  505  may include the functions illustrated in  FIG. 2 , such as a third upper layer  202   c  and a third data transceiving function  208   c  for example. 
     Still referring to  FIGS. 8 and 9 , a peer may participate in multiple P2P services or applications simultaneously in accordance with an example embodiment. Thus, a peer may participate in multiple P2P sessions that overlap in time, as described below. Further, the multiple P2P sessions that overlap in time may use different applications. The context-aware architecture  200  may enable multi-application capability for P2P communications in proximity. 
     An example multi-application data transmission is illustration in  FIG. 8 . Referring in particular to  FIG. 8 , the first peer  502  and the second peer  505  may start a first P2P session with each other for a first application (Application  1 ), as described above with reference to  FIG. 5 . Further, the first peer  502  and the second peer  504  may start a second P2P session with each other for a second application (Application  2 ) that is different than Application  1 . At  802 , in accordance with the illustrated example, the first upper layer  202   a  sends a trigger or request that includes MCPS-DATA-APP Lrequest to the first data transceiving function  208   a  of the first peer  502 . At  804 , the first Upper Layer  202   a  downloads context information related to Application 1  via the Context Management Function. At  806 , the first Data Transceiving Function  208   a  sends data associated with Application 1 , to the third peer  505  over the air (via an air interface). At  808 , as shown, the third peer  505  receives the data and notifies the third Upper Layer  202   c  with an MCPS-DATA-APP 1 .indication. At  809 , the third peer  505  sends an acknowledgement (ACK) for the data associated with Application 1  to the first peer  502  via air the interface between the first and third peers  502  and  505 . At  810 , the first peer  502  receives the ACK and notifies the first Upper Layer  202   a  with a message that includes the MCPS-DATA-APP 1 .confirm primitive. Thus, at  812 , the first peer  502  may update the context and upload the updated Application 1  context to the first Upper Layer  202   a  via the first Context Information Management function  210   a.    
     Still referring to  FIG. 8 , in accordance with the illustrated example, at  814 , the first Upper Layer  202   a  sends a trigger or a request (MCPS-DATA-APP 2 .request) to the Data Transceiving Function  208   a . Further, at  816 , the upper layer  202   a  downloads context information related to the second application (Application 2 ) via the Context Management Function. At  818 , the first Data Transceiving Function  208   a  sends data association with Application 2  to the second peer  504  via the air interface. At  820 , the second peer  504  receives the data and notifies the second Upper Layer  202   b  with MCPS-DATA-APP 2 .indication. At  822 , the second peer  504  sends an ACK for the data associated with the Application 2  to the first peer  502  via the air interface. At  824 , in accordance with the illustrated example, the first peer  502  receives the ACK and notifies the first Upper Layer  202   a  with the MCPS-DATA-APP 2 .confirm message. At  826 , the first peer  504  may update the context and upload the updated Application 2  context to the first Upper Layer  202   a  via the first Context Information Management function  210   a.    
     Referring now to  FIG. 9 , it will be understood that like reference numbers are repeated in various figures to indicate the same or similar features. In accordance with the illustrated example, at  902 , the second Upper Layer  202   b  sends a data transmission request to the second Data Transceiving Function  208   b . At  904 , the second Data Transceiving Function  208   b  sends data associated with Application 2  to the first peer  502  via the air interface. At  906 , in accordance with the illustrated embodiment, the third peer  505  receives the Application 1  Data from the first peer  502  and notifies the third Upper Layer  202   c  with an MCPS-DATA-APP 1 .indication. At  908 , the third peer  505  sends an ACK, in response to the receiving the data association with Application), the first peer  502  via the air interface. At  910 , the first peer  502  receives data associated with Application 2  from the second peer  504  and notifies the first Upper Layer  202   a  with a MCPS-DATA-APP 2 .indication. At  912 , the first peer  504  sends an ACK for the Application 2  data to the second peer  504  via the air interface. At  914 , in accordance with the illustrated example, the first peer  504  receives the ACK from the third peer  505  for the data associated with Application 1  and notifies the Upper Layer  202   a  with MCP S-DATA-APP 1 .confirm. At  916 , the second peer  504  receives the ACK from the first peer  502  and notifies the second Upper Layer  202   b  with MCPS-DATA-APP 2 .confirm. 
       FIG. 10A  is a diagram of an example machine-to machine (M2M), Internet of Things (IoT), or Web of Things (WoT) communication system  10  in which one or more disclosed embodiments may be implemented. For example, the architecture and peers described with reference to  FIGS. 2-9  may be implemented on various devices depicted in  FIG. 10A , as described further below. Generally, M2M technologies provide building blocks for the IoT/WoT, and any M2M device, gateway or service platform may be a component of the IoT/WoT as well as an IoT/WoT service layer, etc. 
     As shown in  FIG. 10A , the M2M/IoT/WoT communication system  10  includes a communication network  12 . The communication network  12  may be a fixed network (e.g., Ethernet, Fiber, ISDN, PLC, or the like) or a wireless network (e.g., WLAN, cellular, or the like) or a network of heterogeneous networks. For example, the communication network  12  may comprise multiple access networks that provide content such as voice, data, video, messaging, broadcast, or the like to multiple users. For example, the communication network  12  may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), and the like. Further, the communication network  12  may comprise other networks such as a core network, the Internet, a sensor network, an industrial control network, a personal area network, a fused personal network, a satellite network, a home network, or an enterprise network for example. 
     As shown in  FIG. 10A , the M2M/IoT/WoT communication system  10  may include the Infrastructure Domain and the Field Domain. The Infrastructure Domain refers to the network side of the end-to-end M2M deployment, and the Field Domain refers to the area networks, usually behind an M2M gateway. The Field Domain includes M2M gateways  14  and terminal devices  18 . It will be appreciated that any number of M2M gateway devices  14  and M2M terminal devices  18  may be included in the M2M/IoT/WoT communication system  10  as desired. The gateway devices  14  or the terminal devices  18  may be configured as peer devices in a system that performs context-aware P2P communications in accordance with the embodiments described above. The gateway devices  14  and/or the terminal devices  18  may be configured as the peer devices described above, and thus each of the gateway devices  14  and the terminal devices  18  may include the architecture  200 . Each of the M2M gateway devices  14  and M2M terminal devices  18  are configured to transmit and receive signals via the communication network  12  or direct radio link. The M2M gateway device  14  allows wireless M2M devices (e.g., cellular and non-cellular) as well as fixed network M2M devices (e.g., PLC) to communicate either through operator networks, such as the communication network  12  or direct radio link. For example, the M2M devices  18  may collect data and send the data, via the communication network  12  or direct radio link, to an M2M application 20 or M2M devices  18 . The M2M devices  18  may also receive data from the M2M application 20 or an M2M device  18 . Further, data and signals may be sent to and received from the M2M application 20 via an M2M service layer  22 , as described below. M2M devices  18  and gateways  14  may communicate via various networks including, cellular, WLAN, WPAN (e.g., Zigbee, 6LoWPAN, Bluetooth), direct radio link, and wireline for example. The terminal devices  18  and the gateway devices  14  may communicate via various networks to exchange P2P messages, as described above. For example, peer-to-peer communications described above can occur directly between multiple terminal devices  18 , directly between multiple gateway devices  14 , or directly between terminal devices  18  and gateway devices  14 . 
     Referring also to  FIG. 10B , the illustrated M2M service layer  22  in the field domain provides services for the M2M application 20, M2M gateway devices  14 , M2M terminal devices  18  and the communication network  12 . It will be understood that the M2M service platform  22  may communicate with any number of M2M applications, M2M gateway devices  14 , M2M terminal devices  18 , and communication networks  12  as desired. The M2M service layer  22  may be implemented by one or more servers, computers, or the like. The M2M service 22 layer provides service capabilities that apply to the M2M terminal devices  18 , the M2M gateway devices  14 , and the M2M applications  20 . The functions of the M2M service layer  22  may be implemented in a variety of ways, for example as a web server, in the cellular core network, in the cloud, etc. 
     Similar to the illustrated M2M service layer  22 , an M2M service layer  22 ′ resides in the infrastructure domain. The M2M service layer  22 ′ provides services for an M2M application 20′ and an underlying communication network  12 ′ in the infrastructure domain. The M2M service layer  22 ′ also provides services for the M2M gateway devices  14  and M2M terminal devices  18  in the field domain. It will be understood that the M2M service layer  22 ′ may communicate with any number of M2M applications, M2M gateway devices, and M2M terminal devices. The M2M service layer  22 ′ may interact with a service layer by a different service provider. The M2M service layer  22 ′ may be implemented by one or more servers, computers, virtual machines (e.g., cloud/compute/storage farms, etc.) or the like. 
     Referring still to  FIG. 10B , the M2M service layers  22  and  22 ′ can provide a core set of service delivery capabilities that diverse applications and verticals can leverage. These service capabilities enable M2M applications  20  and  20 ′ to interact with devices and perform functions such as data collection, data analysis, device management, security, billing, service/device discovery, etc. Essentially, these service capabilities can free the applications of the burden of implementing these functionalities, thus simplifying application development and reducing cost and time to market. The service layers  22  and  22 ′ also may enable M2M applications  20  and  20 ′ to communicate through various networks  12  and  12 ′ in connection with the services that the service layers  22  and  22 ′ provide. 
     The MAC/PHY layer functions of the present application may communicate with a service layer. As used herein, a service layer may refer to a software middleware layer that supports value-added service capabilities through a set of Application Programming Interfaces (APIs) and underlying networking interfaces. Both ETSI M2M and oneM2M use a service layer that may implement the MAC/PHY layer functions described herein. ETSI M2M&#39;s service layer is referred to as the Service Capability Layer (SCL). Embodiments described herein may be implemented as part of the SCL, wherein the messages may be based on various protocols such as, for example, MQTT or AMQP. The SCL may be implemented within an M2M device (where it is referred to as a device SCL (DSCL)), a gateway (where it is referred to as a gateway SCL (GSCL)) and/or a network node (where it is referred to as a network SCL (NSCL)). The oneM2M service layer supports a set of Common Service Functions (CSFs) (e.g., service capabilities). An instantiation of a set of one or more particular types of CSFs is referred to as a Common Services Entity (CSE) which can be hosted on different types of network nodes (e.g. infrastructure node, middle node, application-specific node). Further, context-aware P2P communications described herein can be implemented as part of an M2M network that uses a Service Oriented Architecture (SOA) and/or a resource-oriented architecture (ROA) to access. Further, the context managers of the present application can implemented as part of an M2M network that uses a Service Oriented Architecture (SOA) and/or a resource-oriented architecture (ROA) to access services such as the context manager of the present application. 
     The M2M applications  20  and  20 ′ may include applications in various industries such as, without limitation, transportation, health and wellness, connected home, energy management, asset tracking, and security and surveillance. As mentioned above, the M2M service layer, running across the devices, gateways, and other servers of the system, supports functions such as, for example, data collection, device management, security, billing, location tracking/geofencing, device/service discovery, and legacy systems integration, and provides these functions as services to the M2M applications  20  and  20 ′. 
       FIG. 10C  is a system diagram of an example M2M device  30 , such as an M2M terminal device  18  or an M2M gateway device  14  for example. The M2M device  30  may be configured as a peer for performing P2P communication, for instance context-aware P2P communication, in accordance with the embodiments described above. As shown in  FIG. 10C , the M2M device  30  may include a processor  32 , a transceiver  34 , a transmit/receive element  36 , a speaker/microphone  38 , a keypad  40 , a display/touchpad/indicators  42 , non-removable memory  44 , removable memory  46 , a power source  48 , a global positioning system (GPS) chipset  50 , and other peripherals  52 . It will be appreciated that the M2M device  30  may include any sub-combination of the foregoing elements while remaining consistent with an embodiment. The display/touchpad/indicators  42  may be generally referred to as a user interface in accordance with an example embodiment. The user interface, which also may be referred to as a context management interface, may allow users to monitor, manage, and/or configure context management on a peer device, such as a gateway or other network node for example. For example, the user interface may enable a user to configure or trigger context information exchange and management between different peers or between different layers. Thus, various context parameters (e.g., context values, context IDs, number of remaining responses, etc.) may be displayed by the display/touchpad/indicators  42 . 
     The processor  32  may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Array (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor  32  may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the M2M device  30  to operate in a wireless environment. The processor  32  may be coupled to the transceiver  34 , which may be coupled to the transmit/receive element  36 . While  FIG. 10C  depicts the processor  32  and the transceiver  34  as separate components, it will be appreciated that the processor  32  and the transceiver  34  may be integrated together in an electronic package or chip. The processor  32  may perform application-layer programs (e.g., browsers) and/or radio access-layer (RAN) programs and/or communications. The processor  32  may perform security operations such as authentication, security key agreement, and/or cryptographic operations, such as at the access-layer and/or application layer for example. 
     The transmit/receive element  36  may be configured to transmit signals to, or receive signals from, an M2M service platform  22 . For example, in an embodiment, the transmit/receive element  36  may be an antenna configured to transmit and/or receive RF signals. The transmit/receive element  36  may support various networks and air interfaces, such as WLAN, WPAN, cellular, and the like. In an embodiment, the transmit/receive element  36  may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit/receive element  36  may be configured to transmit and receive both RF and light signals. It will be appreciated that the transmit/receive element  36  may be configured to transmit and/or receive any combination of wireless or wired signals. 
     In addition, although the transmit/receive element  36  is depicted in  FIG. 10C  as a single element, the M2M device  30  may include any number of transmit/receive elements  36 . More specifically, the M2M device  30  may employ MIMO technology. Thus, in an embodiment, the M2M device  30  may include two or more transmit/receive elements  36  (e.g., multiple antennas) for transmitting and receiving wireless signals. 
     The transceiver  34  may be configured to modulate the signals that are to be transmitted by the transmit/receive element  36  and to demodulate the signals that are received by the transmit/receive element  36 . As noted above, the M2M device  30  may have multi-mode capabilities. Thus, the transceiver  34  may include multiple transceivers for enabling the M2M device  30  to communicate via multiple RATs, such as UTRA and IEEE 802.11, for example. 
     The processor  32  may access information from, and store data in, any type of suitable memory, such as the non-removable memory  44  and/or the removable memory  46 . For example, the processor  32  may store and access context information, as described above, from the non-removable memory  44  and/or the removable memory  46  to determine whether there is context information that satisfies a context information request. The non-removable memory  44  may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory  46  may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor  32  may access information from, and store data in, memory that is not physically located on the M2M device  30 , such as on a server or a home computer. 
     The processor  32  may receive power from the power source  48 , and may be configured to distribute and/or control the power to the other components in the M2M device  30 . The power source  48  may be any suitable device for powering the M2M device  30 . For example, the power source  48  may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like. 
     The processor  32  may also be coupled to the GPS chipset  50 , which is configured to provide location information (e.g., longitude and latitude) regarding the current location of the M2M device  30 . It will be appreciated that the M2M device  30  may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment. 
     The processor  32  may further be coupled to other peripherals  52 , which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals  52  may include an accelerometer, an e-compass, a satellite transceiver, a sensor, a digital camera (for photographs or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, and the like. 
       FIG. 10D  is a block diagram of an exemplary computing system  90  on which, for example, the M2M service platform  22  of  FIGS. 10A and 10B  may be implemented. Computing system  90  may comprise a computer or server and may be controlled primarily by computer readable instructions, which may be in the form of software, wherever, or by whatever means such software is stored or accessed. Such computer readable instructions may be executed within central processing unit (CPU)  91  to cause computing system  90  to do work. In many known workstations, servers, and personal computers, central processing unit  91  is implemented by a single-chip CPU called a microprocessor. In other machines, the central processing unit  91  may comprise multiple processors. Coprocessor  81  is an optional processor, distinct from main CPU  91 , that performs additional functions or assists CPU  91 . 
     In operation, CPU  91  fetches, decodes, and executes instructions, and transfers information to and from other resources via the computer&#39;s main data-transfer path, system bus  80 . Such a system bus connects the components in computing system  90  and defines the medium for data exchange. System bus  80  typically includes data lines for sending data, address lines for sending addresses, and control lines for sending interrupts and for operating the system bus. An example of such a system bus  80  is the PCI (Peripheral Component Interconnect) bus. 
     Memory devices coupled to system bus  80  include random access memory (RAM)  82  and read only memory (ROM)  93 . Such memories include circuitry that allows information to be stored and retrieved. ROMs  93  generally contain stored data that cannot easily be modified. Data stored in RAM  82  can be read or changed by CPU  91  or other hardware devices. Access to RAM  82  and/or ROM  93  may be controlled by memory controller  92 . Memory controller  92  may provide an address translation function that translates virtual addresses into physical addresses as instructions are executed. Memory controller  92  may also provide a memory protection function that isolates processes within the system and isolates system processes from user processes. Thus, a program running in a first mode can access only memory mapped by its own process virtual address space; it cannot access memory within another process&#39;s virtual address space unless memory sharing between the processes has been set up. 
     In addition, computing system  90  may contain peripherals controller  83  responsible for communicating instructions from CPU  91  to peripherals, such as printer  94 , keyboard  84 , mouse  95 , and disk drive  85 . 
     Display  86 , which is controlled by display controller  96 , is used to display visual output generated by computing system  90 . Such visual output may include text, graphics, animated graphics, and video. Display  86  may be implemented with a CRT-based video display, an LCD-based flat-panel display, gas plasma-based flat-panel display, or a touch-panel. Display controller  96  includes electronic components required to generate a video signal that is sent to display  86 . 
     Further, computing system  90  may contain network adaptor  97  that may be used to connect computing system  90  to an external communications network, such as network  12  of  FIGS. 10A and 10B . 
     It is understood that any or all of the systems, methods and processes described herein may be embodied in the form of computer executable instructions (i.e., program code) stored on a computer-readable storage medium with instructions, when executed by a machine, such as a computer, server, peer, M2M terminal device, M2M gateway device, or the like, perform and/or implement the systems, methods and processes described herein. Specifically, any of the steps, operations or functions described above may be implemented in the form of such computer executable instructions. Computer readable storage media include both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, but such computer readable storage media do not includes signals. Computer readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CDROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other physical medium which can be used to store the desired information and which can be accessed by a computer. 
     In describing preferred embodiments of the subject matter of the present disclosure, as illustrated in the figures, specific terminology is employed for the sake of clarity. The claimed subject matter, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.