Opportunistic data forwarding and dynamic reconfiguration in wireless local area networks

Mobile communication devices and wireless network device each can participate in, or solely provide, opportunistic data forwarding in a wireless network such as a wireless local area network or radio access network. A supporting node receives wireless communication between a transmitting node and a receiving node comprising packet data units (PDUs). The receiving node communicates to the transmitting node that one or more portions of the communication were not received, which is overheard by the supporting node. The supporting node can have sufficient over-the-air (OTA) allocation in its transmit opportunity to relay the failed portions to the receiving node. Thereby, techniques such as more robust error encoding, longer transmit allocations, etc., that would reduce the effective data throughput for OTA resources are avoided while providing an ability to more rapidly adapt to a changing channel state.

FIELD OF INVENTION

The following description relates generally to wireless communications, and more particularly to managing transmission and reception in a wireless communication environment.

BACKGROUND

Recent developments in a number of different digital technologies have greatly increased the need to transfer large amounts of data from one device to another or across a network to another system. Technological developments permit digitization and compression of large amounts of voice, video, imaging, and data information, which may be rapidly transmitted from computers and other digital equipment to other devices within the network. Computers have faster central processing units and substantially increased memory capabilities, which have increased the demand for devices that can more quickly transfer larger amounts of data.

Increasingly, these uses have migrated to portable devices. Wireless communication devices have become smaller and more powerful in order to meet consumer needs and to improve portability and convenience. The increase in processing power in mobile devices such as cellular telephones has led to an increase in demands on wireless network transmission systems. Thus, increasing numbers of portable devices compete for scarce over-the-air resources. Mobility, environmental obstructions, and interfering sources (e.g., transmit collisions between wireless communication devices) can make it difficult to successfully communicate with another node in a local access network or radio access network. Channel quality can rapidly fade or be impacted with a dynamically changing signal-to-noise ratio that challenges successful communication.

SUMMARY

The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed aspects. This summary is not an extensive overview and is intended to neither identify key or critical elements nor delineate the scope of such aspects. Its purpose is to present some concepts of the described features in a simplified form as a prelude to the more detailed description that is presented later.

In accordance with one or more aspects and corresponding disclosure thereof, various aspects are described in connection with performing opportunistic data forwarding and dynamic reconfiguration in a wireless communication system, such as a wireless local access network or radio access network. In situations in which a transmitting node is still within range of a receiving node, formally setting up a multi-hop ad hoc network can be unadvisable, especially if failing to receive certain data packets is due to intermittent interference. Over-the-air (OTA) resources can be better utilized if another node, referred to as a supporting node, relays those data packets that the receiving node signals as having failed without having to wait for the transmitting node to have another opportunity to retransmit. Dynamically reconfiguring a wireless local network can respond to rapidly changing channel states, optimize OTA resources, avoid degraded time-critical communication due to missed data packets, and distribute administrative overhead.

In one aspect, a method provides for opportunistic data forwarding in a wireless network. Wireless communication between a transmitting node and a receiving node comprising packet data units (PDUs) is received. A communication from the receiving node to the transmitting node is received at a supporting node indicating a failure to receive a PDU. The PDU that was indicated to have failed is transmitted to the receiving node from the supporting node.

In another aspect, at least one processor provides for opportunistic data forwarding in a wireless network. A first module receives wireless communication between a transmitting node and a receiving node comprising packet data units (PDUs). A second module receives a communication at a supporting node from the receiving node to the transmitting node indicating a failure to receive a PDU. A third module transmits the PDU that was indicated to have failed to the receiving node from the supporting node.

In an additional aspect, a computer program product provides for opportunistic data forwarding in a wireless network by comprising computer-readable storage medium having sets of codes. A first set of codes causes a computer to receive wireless communication between a transmitting node and a receiving node comprising packet data units (PDUs). A second set of codes causes the computer to receive a communication at a supporting node from the receiving node to the transmitting node indicating a failure to receive a PDU. A third set of codes causes the computer to transmit the PDU that was indicated to have failed to the receiving node from the supporting node.

In another additional aspect, an apparatus provides for opportunistic data forwarding in a wireless network. Means are provided for receiving wireless communication between a transmitting node and a receiving node comprising packet data units (PDUs). Means are provided for receiving a communication at a supporting node from the receiving node to the transmitting node indicating a failure to receive a PDU. Means are provided for transmitting the PDU that was indicated to have failed to the receiving node from the supporting node.

In a further aspect, a mobile communication devices and wireless network device each can participate in or solely provide opportunistic data forwarding in a wireless network. A receiver receives wireless communication between a transmitting node and a receiving node comprising packet data units (PDUs), and receives a communication at a supporting node from the receiving node to the transmitting node indicating a failure to receive a PDU. A transmitter transmits the PDU that was indicated to have failed to the receiving node from the supporting node.

In yet one aspect, a method provides for opportunistic data forwarding in a wireless network. Wireless communication from a transmitting node comprising packet data units (PDUs) is received. A failure to receive a PDU is determined. Communication is transmitted to the transmitting node indicating a failure to receive a PDU. The PDU is received from a supporting node responding to the communication to the transmitting node.

In yet another aspect, at least one processor provides for opportunistic data forwarding in a wireless network. A first module receives wireless communication from a transmitting node comprising packet data units (PDUs). A second module determines a failure to receive a PDU. A third module transmits a communication to the transmitting node indicating a failure to receive a PDU. A fourth module receives the PDU from a supporting node responding to the communication to the transmitting node.

In yet an additional aspect, a computer program product provides for opportunistic data forwarding in a wireless network by comprising a computer-readable storage medium containing sets of codes. A first set of codes causes a computer to receive wireless communication from a transmitting node comprising packet data units (PDUs). A second set of codes causes the computer to determine a failure to receive a PDU. A third set of codes causes the computer to transmit a communication to the transmitting node indicating a failure to receive a PDU. A fourth set of codes causes the computer to receive the PDU from a supporting node responding to the communication to the transmitting node.

In yet another additional aspect, an apparatus provides for opportunistic data forwarding in a wireless network. Means are provided for receiving wireless communication from a transmitting node comprising packet data units (PDUs). Means are provided for determining a failure to receive a PDU. Means are provided for transmitting a communication to the transmitting node indicating a failure to receive a PDU. Means are provided for receiving the PDU from a supporting node responding to the communication to the transmitting node.

In yet a further aspect, an apparatus provides for opportunistic data forwarding in a wireless network. A receiver receives wireless communication from a transmitting node comprising packet data units (PDUs). A processor determines a failure to receive a PDU. A transmitter transmits a communication to the transmitting node indicating a failure to receive a PDU. The receiver receives the PDU from a supporting node responding to the communication to the transmitting node.

To the accomplishment of the foregoing and related ends, one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects and are indicative of but a few of the various ways in which the principles of the aspects may be employed. Other advantages and novel features will become apparent from the following detailed description when considered in conjunction with the drawings and the disclosed aspects are intended to include all such aspects and their equivalents.

DETAILED DESCRIPTION

Opportunistic data forwarding and dynamic reconfiguration is achieved in a communication system, such as a wireless local area network (e.g., IEEE 802.11n) or in a radio access network, in order to more rapidly and efficiently respond to a changing channel state. In general, a node may have successfully received packets sent by one or more nodes in the vicinity to a given receiver, and is aware that these transmissions have failed. It forwards such previously failed packets in the remaining time available for it to transmit data to the receiver. If a significant number of packets are received through such data forwarding by an intermediate node, then the routing path can be modified to include this intermediate node. When the routing path is modified for a given flow, then the transmission opportunity time for the intermediate node is increased (or the number of transmission opportunities for the intermediate node is increased) to accommodate the new flow through the intermediate node.

The innovation is applicable to a number of short range wireless communication protocols such as IEEE 802.15.3 MAC/PHY (Ultrawideband), IEEE 802.15.4 MAC/PHY that supports sensor protocols such as Zigbee and 6LOWPAN, 802.11.x (WLAN-based) protocols, Bluetooth, and longer range protocols such as CDMA2000 (1xRTT, EV-DO, EV-DV, EV-DO RevB), GSM/GRPS/EGPRS, UMTS, HSDPA/HSUPA, HSPA-plus, UMB, WiMAX, or LTE), where such wireless protocols may be enhanced to allow an intermediate node to opportunistically forward failed packets. For purposes of illustration, we will use a WLAN-based protocol.

As used in this application, the terms “component”, “module”, “system”, and the like are intended to refer to a computer-related entity, either hardware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, or a computer. By way of illustration, both an application running on a server and the server can be a component. One or more components may reside within a process or thread of execution and a component may be localized on one computer or distributed between two or more computers.

Various aspects will be presented in terms of systems that may include a number of components, modules, and the like. It is to be understood and appreciated that the various systems may include additional components, modules, etc. or may not include all of the components, modules, etc. discussed in connection with the figures. A combination of these approaches may also be used. The various aspects disclosed herein can be performed on electrical devices including devices that utilize touch screen display technologies or mouse-and-keyboard type interfaces. Examples of such devices include computers (desktop and mobile), smart phones, personal digital assistants (PDAs), and other electronic devices both wired and wireless.

With reference toFIG. 1, a wireless network100is formed between a transmitting node “T”102and a receiving node “R”104as detected by another node “S”106that volunteers to support the communication. In particular, in addition to capturing its own queue108in a buffer110, the node S also maintains a sniffed queue112for neighboring nodes. Contents of the sniffed queue112can be routinely maintained in the event that an opportunity for data forward arising. Alternatively, such buffering can be initiated upon an initiating event, such as a request from node T102or node R104. Alternatively, such buffering can be initiated when the node S106detects a previous incident of communication failure between nodes T & S102,104. Such buffering and opportunistic data forwarding can also be contingent upon available excess capacity by the node S106. Consider that node T102needs to send some medium access channel (MAC) protocol data units (PDUs), that is MPDUs120, to node R. Protocols such as 802.11n allow aggregated transmission of MPDUs. Due to a channel state of an air link122between the node T102and node R104, a portion124of the A-MPDU120is not received by the node R104, as almost immediately announced by the node R104that is robustly transmitted back over air link122to node T102as a Nak126.

The node S106in the depicted scenario receives the A-MPDU120successfully over an air link128and has buffered them in the sniffed queue112. When the node S106receives the Nak126over its air link130with the node R104, the node S106is able to relay a tagged version132of the missing portion124to the access node R102.

In one aspect, the transmitting node102can communicate over air link122with the receiving node104using a first wireless protocol “A”. The supporting node106can sniff this communication using the first wireless protocol A, although the supporting node106communicates with the transmitting node102over airlink128using wireless protocol B. The supporting node106can communicate with the receiving node104with a wireless protocol C. Alternatively, two or three of the air links122,128,130can support communication via a common wireless protocol.

In one illustrative aspect depicted inFIG. 2, an over-the-air (OTA) or wireless communication channel200is shared by a node T202, node R204, and node S206. The node T202has burst TxOP (transmission opportunity) times208,210to send data to another node R204. In an illustrative scenario, the TxOPs208,210are 2 ms in duration and are widely spaced to allow other nodes to access the communication channel200. The medium access channel (MAC) of the node T202converts higher protocol service data units (SDUs)212into a plurality of MPDUs, depicted as ten MPDUs214of 150 μs each. If the node T202creates an A-MPDU216for ten MPDUs214, then 1.5 ms of the available 2.0 ms of TxOP208are used.

The node R204would perform a check to see if the data was received successfully, which in the illustrative implementation entails a cyclic redundancy check (CRC) and an Ack or Nak218within 16 μs. Thus, if a collision or other interference220occurs as depicted, certain MPDUs could be prevented from being successfully transmitted. In particular, the block acknowledgement comes back indicating that some MPDU transmissions have failed the cyclic redundancy check (CRC) check, or the block acknowledgement itself fails. The flow is “bursty” with node T sending information to node R in bursts of MPDUs when it gets a transmission opportunity to send data to R. The MPDUs can be too late as depicted at224to be retransmitted when node T gets its next transmission opportunity to send data to R.

Advantageously, node S206in the vicinity of node T and R202,204monitors transmissions from node T to node R202,204. The node S206also observes the block acknowledgement218from node R to node T204,202. The block acknowledgement218shows that transmission of one or more MPDU(s)214has failed. However, node S206has correctly received the MPDU(s)214after monitoring the transmission, and verifying that the CRC check has passed. When node S206has a transmission opportunity to transmit to node R, depicted as TxOP226, if it has additional time available, it sends to R, these failed MPDU transmissions from node T to node R202,204that it has successfully received. Node R204sends a block acknowledgement indicating to both nodes S and T206,202of the MPDUs214that it has successfully received from node S206. This obviates the need for node T202to retransmit failed MPDUs214to node R204.

An example wireless network may include battery-operated computing and sensing devices (nodes) that collaborate to deliver sensed data, often over multiple hops. Nodes of the wireless network may communicate using any wireless protocol. For example IEEE 802.11b/g/n and/or Bluetooth may be used. IEEE 802.11b corresponds to IEEE Std. 802.11b-1999 entitled “Local and Metropolitan Area Networks, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Higher-Speed Physical Layer Extension in the 2.4 GHz Band,” approved Sep. 16, 1999 as well as related documents. IEEE 802.11g corresponds to IEEE Std. 802.11g-2003 entitled “Local and Metropolitan Area Networks, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, Amendment 4: Further Higher Rate Extension in the 2.4 GHz Band,” approved Jun. 27, 2003 as well as related documents. Related documents may include, for example, IEEE 802.11a. IEEE 802.11n is an addition to the 802.11 family of standards that is intended to increase wireless network speed and reliability. Bluetooth protocols are described in “Specification of the Bluetooth System: Core, Version 1.1,” published Feb. 22, 2001 by the Bluetooth Special Interest Group, Inc. Associated as well as previous or subsequent versions of the Bluetooth standard may also be supported.

InFIG. 3, in another aspect, a wireless network300has a transmitting terminal “T”01depicted as an access node “T”302and a supporting access terminal “S” depicted as an access node “S”306within a wireless local access network (WLAN) coverage area305provided by a receiving node R depicted as an access point304. The access point (node R)304also interfaces with a wired network308, such as a public or private data packet network (e.g., Internet). The access node S306has an opportunistic data forwarding component310that utilizes an own queue312and sniffed queue314in a buffer316as described above with regard toFIGS. 1-2to perform opportunistic data forwarding.

Advantageously, the access point304or another administrator node “A”318that is also in communication to the WLAN305include a dynamic reconfiguration component320that benefits from monitoring opportunistic data forwarding. Thus, when the channel state of air link322between the access node T302and the access point (node R)304fails as depicted at324, then the administrator node A318can command entities within the WLAN305to set up a routing path326with the supporting node S306serving as intermediate node, setting up an intermediate queue328. The administrator node A318benefits by a self-identified volunteer to assist the transmitting access node T302, which implies sufficient capacity, available power, and having a suitable air link330with the node T302and a suitable air link332with the access point304, thereby avoiding time-consuming overhead negotiations with various nodes to select an intermediate node.

The administrator node A318can further include an assisting node goodness rating component334that evaluates how helpful various nodes have been in performing opportunistic data forwarding. Such ratings can be disseminated by broadcast to nodes within the WLAN coverage area305to assist them in deciding whether to participate in opportunistic data forwarding. Favorable ratings can result in higher uplink allocations or other preferential treatment, such as managed and tracked by an over-the-air (OTA) resource allocation component336.

Alternatively or in addition, the supporting node S306can recognize that more than opportunistic data forwarding is called for and initiate setting up a multi-hop routing path.

In an illustrative aspect depicted inFIG. 4, a methodology400for opportunistic data forwarding and dynamic reconfiguration is performed by a burst-oriented wireless network402. In particular, consider a wireless communication system in which medium access control (MAC) contention protocols are relied upon to compete for uplink resources. Transmission opportunities (TxOP)102are constrained with significant delays imposed between subsequent TxOPs102to give other wireless nodes access to the channel. Certain large format data protocols, such as aggregated MAC protocol data units (A-MPDUs) can largely exhaust available TxOP. Robust error correction coding may be inappropriate, especially for certain media forms like Voice over IP (VoIP), streaming video, digital images, etc., that are already large consumers of OTA resources. Yet, failure to successfully transmit each PDU of the A-MPDU can reduce quality of service with degraded audio/video playback as failed PDUs can expire

InFIG. 4, a methodology400performs opportunistic data forwarding and dynamic reconfiguration within a wireless network depicted as a transmitting access node “T”402, a receiving access node “R”404, and a proximally positioned supporting access node “S”406. In block408, the supporting access node S406is buffering sniffed A-MPDUs, which can be a routinely performed in order to identify communications pertinent to the node406. The node S406can buffer for a longer period in order to determine if any are needed for opportunistic data forwarding. Buffering can be more targeted, such as singled out for nodes detected as having difficulty communicating or after having been requested. Buffering can also be dependent upon available resources (e.g., data throughput, memory, power, computing capacity, etc.).

The transmitting access node T402aggregates MPDUs in block410, sending to receiving node R404, which is only partially successful as depicted at412. The supporting node S406successfully overhears or sniffs the A-MPDU as depicted at414. The receiving node R404performs a check, depicted as a cyclic redundancy check (CRC) in block416, although other checks can be performs alternatively or in addition to determine what portions of the transmission failed. The receiving access node R404communicates the successes and failures of transmission, depicted as Ack/Nak at418to the transmitting access node402, which is overheard/sniffed by the supporting access node S406as depicted at420. The TxOP for the transmitting access node T402expires as depicted at422before retransmission can occur, so the transmitting access node T402sleeps until the next TxOP (block424).

The supporting access node S406in block426can determine whether or not to perform opportunistic data forwarding. Various factors can be weighted in making this determination, such as whether or not the failed PDUs are time critical, whether or not channel state is such that the transmitting access node402will have another opportunity to retransmit in time. Another factor can be the availability of resources of the supporting access node S406(e.g., battery power, buffer, computing power, own transmission allocations and queued data, etc.). If participating, then the missing PDU(s) are tagged and included in the burst transmission by the supporting access node S406(block428), which is sent to the receiving access node R404as depicted at430, which in turn responds with an Ack to the transmitting access node T432and to the supporting access node S406as depicted at434. Thus, the whole A-MPDU has been successfully received by the receiving access node R404before the PDUs expire as depicted at436that occurs before the transmitting access node402has another TxOP to retransmit. Thus, the portion438of the methodology400for opportunistic data forwarding concludes.

A dynamic reconfiguration portion440of the methodology400can benefit from monitoring the opportunistic data forwarding portion438. If node S404observes that a significant number of MPDUs have failed from node T402to node R404, and if node T402observes that the node S406is successful in transmitted such MPDUs to node R404based on the acknowledgement from node R404, then node T402dynamically can elects to use a multi-hop path (block442) to route MPDUs to node R404via node S406as depicted at444.

InFIG. 5, in another aspect, an access node, depicted as an access terminal500, includes modules that provide a means to cause a computer to manage opportunistic data forwarding in a wireless network. Access terminal500comprises a receiver502that receives a signal from, for instance, a receive antenna504, and performs typical actions thereon (e.g., filters, amplifies, downconverts, etc.) the received signal and digitizes the conditioned signal to obtain samples. Receiver502can be operatively associated with a demodulator506that demodulates received signals and provides them to a processor508for channel estimation. Processor508may be a processor dedicated to analyzing information received by receiver502and/or generating information for transmission by a transmitter510, a processor that is part of a computing platform510that controls one or more components of access terminal500, and/or a processor that both analyzes information received by receiver502, generates information for transmission by transmitter512, and controls one or more components of access terminal500. The processor508sends signals to a modulator514for filtering, amplification, upconverts, modulation, etc., then to the transmitter512for transmitting over a transmitter (Tx) antenna516.

Additionally, processor508may execute instructions contained in a computer-readable storage medium (memory)518that comprises opportunistic data forwarding and dynamic reconfiguration (ODFDR) component520and that may store data to be transmitted, received data, and the like. It will be appreciated that the data store (e.g., memory518) described herein can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. By way of illustration, and not limitation, nonvolatile memory can include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable PROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM), which acts as external cache memory. By way of illustration and not limitation, RAM is available in many forms such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM). The memory518of the subject systems and methods is intended to comprise, without being limited to, these and any other suitable types of memory.

The ODFDR component520has a module522that provides a means for receiving wireless communication between a transmitting node and a receiving node comprising packet data units (PDUs), depicted as a module518. The ODFDR component520has a module524that provides means for receiving a communication at a supporting node from the receiving node to the transmitting node indicating a failure to receive a PDU. The ODFDR component520has a module526that provides a means for transmitting the PDU that was indicated to have failed to the receiving node from the supporting node.

In one aspect, the access terminal500is capable of aggregating and deaggregating MAC PDUs by a module528. A module530tracks neighboring nodes that assist others by performing opportunistic data forwarding. A module532is detects when it is necessary or desirable to performing peer-to-peer communication protocol in order to set up or respond to requests for acting as an intermediate node based in part upon the tracking by module530. An own queue534buffers data that is to be transmitted. A sniffed queue536retains data packets overheard from other nodes. A multi-hop intermediate queue538supports acting as an intermediate node. A wireless local access networking communication module540supports wireless communication protocols for communicating with an access point. A peer-to-peer communication module542supports the protocols necessary for peer-to-peer communication. A module544manages sleeping states for the access terminal500to extend service life of power supply546for portable applications.

FIG. 6is an illustration of a system600that facilitates opportunistic data forwarding and dynamic reconfiguration. System600comprises an access point602with a receiver604that receives signal(s) from one or more access terminals606through a plurality of receive antennas608, and a transmitter610that transmits to the one or more access terminals606through one or more transmit antennas612as modulated by a modulator614. Receiver604can receive information from receive antennas608and is operatively associated with a demodulator616that demodulates received information. Demodulated symbols are analyzed by a processor618that may be similar to the processor described above with regard toFIG. 5, and which is coupled to a memory620to form a computing platform622that stores information related to and instructions contained in an opportunistic data forwarding and dynamic reconfiguration (ODFDR) component624, and any other suitable information related to performing the various actions and functions set forth herein.

The ODFDR component624can comprise a module626that provides a means for receiving wireless communication from a transmitting node comprising packet data units (PDUs) and means for receiving the PDU from a supporting node responding to the communication to the transmitting node. The ODFDR component624can comprise a module628that provides a means for determining a failure to receive a PDU. The ODFDR component624can comprise a module630that provides a means for transmitting a communication to the transmitting node indicating a failure to receive a PDU. The ODFDR component624can also comprise a module632for aggregating/deaggregating MPDUs, a module634for managing a wireless network that utilizes allocations or protocols for burst transmission opportunities TxOp, a module636for ad hoc network intermediate node assignments, and a module638for wireless local access networking communication. A network communication module640under control of the processor618can interface to a wired network642.

Aspects disclosed herein have application to various types of wireless communication systems. In particular, it should be appreciated that wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP LTE systems, and orthogonal frequency division multiple access (OFDMA) systems.

Example wireless networks include cellular-based data systems. The following are several such examples: (1) the “TIA/EIA-95-B Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System” (the IS-95 standard), (2) the standard offered by a consortium named “3rd Generation Partnership Project” (3GPP) and embodied in a set of documents including Document Nos. 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214 (the W-CDMA standard), (3) the standard offered by a consortium named “3rd Generation Partnership Project 2” (3GPP2) and embodied in “TR-45.5 Physical Layer Standard for cdma2000 Spread Spectrum Systems” (the IS-2000 standard), and (4) the high data rate (HDR) system that conforms to the TIA/EIA/IS-856 standard (the IS-856 standard).

Other examples of wireless systems include Wireless Local Area Networks (WLANs) such as the IEEE 802.11 standards (i.e. 802.11 (a), (b), or (g)). Improvements over these networks may be achieved in deploying a Multiple Input Multiple Output (MIMO) WLAN comprising Orthogonal Frequency Division Multiplexing (OFDM) modulation techniques. IEEE 802.11(e) has been introduced to improve upon some of the shortcomings of previous 802.11 standards.

IEEE 802.11n is a proposed amendment to the IEEE 802.11-2007 wireless networking standard to significantly improve network throughput over previous standards, such as 802.11b and 802.11g, with a significant increase in raw (PHY) data rate from 54 Mbit/s to a maximum of 600 Mbit/s. Most devices today support a PHY rate of 300 Mbit/s, with the use of 2 Spatial Streams at 40 MHz. Depending on the environment, this may translate into a user throughput (TCP/IP) of 100 Mbit/s. IEEE 802.11n builds on previous 802.11 standards by adding multiple-input multiple-output (MIMO) and Channel-bonding/40 MHz operation to the physical (PHY) layer, and frame aggregation to the MAC layer.

MIMO uses multiple transmitter and receiver antennas to improve the system performance. MIMO is a technology which uses multiple antennas to coherently resolve more information than possible using a single antenna. Two important benefits it provides to 802.11n are antenna diversity and spatial multiplexing. MIMO technology relies on multipath signals. Multipath signals are the reflected signals arriving at the receiver some time after the line of sight (LOS) signal transmission has been received. In a non-MIMO based 802.11a/b/g network, multipath signals were perceived as interference degrading a receiver's ability to recover the message information in the signal. MIMO uses the multipath signal's diversity to increase a receiver's ability to recover the message information from the signal.

Another ability MIMO technology provides is Spatial Division Multiplexing (SDM). SDM spatially multiplexes multiple independent data streams, transferred simultaneously within one spectral channel of bandwidth. MIMO SDM can significantly increase data throughput as the number of resolved spatial data streams is increased. Each spatial stream requires a discrete antenna at both the transmitter and the receiver. In addition, MIMO technology requires a separate radio frequency chain and analog-to-digital converter for each MIMO antenna which translates to higher implementation costs compared to non-MIMO systems.

Channel Bonding, also known as 40 MHz, is a second technology incorporated into 802.11n which can simultaneously use two separate non-overlapping channels to transmit data. Channel bonding increases the amount of data that can be transmitted. 40 MHz mode of operation uses 2 adjacent 20 MHz bands. This allows direct doubling of the PHY data rate from a single 20 MHz channel. (Note however that the MAC and user level throughput will not double.) Coupling MIMO architecture with wider bandwidth channels offers the opportunity of creating very powerful yet cost-effective approaches for increasing the physical transfer rate.

A MIMO system supports a time division duplex (TDD) and frequency division duplex (FDD) systems. In a TDD system, the forward and reverse link transmissions are on the same frequency region so that the reciprocity principle allows the estimation of the forward link channel from the reverse link channel. This enables the access point to extract transmit beamforming gain on the forward link when multiple antennas are available at the access point.

Referring toFIG. 7, a multiple access wireless communication system according to one aspect is illustrated. An access point700(AP) includes multiple antenna groups, one including704and706, another including708and710, and an additional including712and714. InFIG. 3, only two antennas are shown for each antenna group, however, more or fewer antennas may be utilized for each antenna group. Access terminal716(AT) is in communication with antennas712and714, where antennas712and714transmit information to access terminal716over forward link720and receive information from access terminal716over reverse link718. Access terminal722is in communication with antennas706and708, where antennas706and708transmit information to access terminal722over forward link726and receive information from access terminal722over reverse link724. In a FDD system, communication links718,720,724and726may use different frequency for communication. For example, forward link720may use a different frequency then that used by reverse link718.

Each group of antennas or the area in which they are designed to communicate is often referred to as a sector of the access point. In the aspect, antenna groups each are designed to communicate to access terminals in a sector, of the areas covered by access point700.

In communication over forward links720and726, the transmitting antennas of access point700utilize beamforming in order to improve the signal-to-noise ratio of forward links for the different access terminals716and724. In addition, an access point using beamforming to transmit to access terminals scattered randomly through its coverage causes less interference to access terminals in neighboring cells than an access point transmitting through a single antenna to all its access terminals.

An access point may be a fixed station used for communicating with the terminals and may also be referred to as an access point, a Node B, or some other terminology. An access terminal may also be called an access terminal, user equipment (UE), a wireless communication device, terminal, access terminal or some other terminology.

FIG. 8is a block diagram of an aspect of a transmitter system810(also known as the access point) and a receiver system850(also known as access terminal) in a MIMO system800. At the transmitter system810, traffic data for a number of data streams is provided from a data source812to a transmit (TX) data processor814.

In an aspect, each data stream is transmitted over a respective transmit antenna. TX data processor814formats, codes, and interleaves the traffic data for each data stream based on a particular coding scheme selected for that data stream to provide coded data.

The modulation symbols for all data streams are then provided to a TX MIMO processor820, which may further process the modulation symbols (e.g., for OFDM). TX MIMO processor820then provides NTmodulation symbol streams to NTtransmitters (TMTR)822athrough822t.In certain implementations, TX MIMO processor820applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transmitter822receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g., amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. NTmodulated signals from transmitters822athrough822tare then transmitted from NTantennas824athrough824t,respectively.

At receiver system850, the transmitted modulated signals are received by NRantennas852athrough852rand the received signal from each antenna852is provided to a respective receiver (RCVR)854athrough854r.Each receiver854conditions (e.g., filters, amplifies, and downconverts) a respective received signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.

An RX data processor860then receives and processes the NR received symbol streams from NRreceivers854based on a particular receiver processing technique to provide NT“detected” symbol streams. The RX data processor860then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by RX data processor860is complementary to that performed by TX MIMO processor820and TX data processor814at transmitter system810.

A processor870periodically determines which pre-coding matrix to use (discussed below). Processor870formulates a reverse link message comprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of information regarding the communication link or the received data stream. The reverse link message is then processed by a TX data processor838, which also receives traffic data for a number of data streams from a data source836, modulated by a modulator880, conditioned by transmitters854athrough854r,and transmitted back to transmitter system810.

At transmitter system810, the modulated signals from receiver system850are received by antennas824, conditioned by receivers822, demodulated by a demodulator840, and processed by a RX data processor842to extract the reserve link message transmitted by the receiver system850. Processor830then determines which pre-coding matrix to use for determining the beamforming weights then processes the extracted message.

In an aspect, logical channels are classified into Control Channels and Traffic Channels. Logical Control Channels comprises Broadcast Control Channel (BCCH), which is DL channel for broadcasting system control information. Paging Control Channel (PCCH), which is DL channel that transfers paging information. Multicast Control Channel (MCCH) which is Point-to-multipoint DL channel used for transmitting Multimedia Broadcast and Multicast Service (MBMS) scheduling and control information for one or several MTCHs. Generally, after establishing RRC connection this channel is only used by UEs that receive MBMS (Note: old MCCH+MSCH). Dedicated Control Channel (DCCH) is Point-to-point bi-directional channel that transmits dedicated control information and used by UEs having an RRC connection. In one aspect, Logical Traffic Channels can comprise a Dedicated Traffic Channel (DTCH), which is Point-to-point bi-directional channel, dedicated to one UE, for the transfer of user information. In addition, a Multicast Traffic Channel (MTCH) for Point-to-multipoint DL channel for transmitting traffic data.

In an aspect, Transport Channels are classified into DL and UL. DL Transport Channels comprises a Broadcast Channel (BCH), Downlink Shared Data Channel (DL-SDCH) and a Paging Channel (PCH), the PCH for support of UE power saving (DRX cycle is indicated by the network to the UE), broadcasted over entire cell and mapped to PHY resources which can be used for other control/traffic channels. The UL Transport Channels comprise a Random Access Channel (RACH), a Request Channel (REQCH), an Uplink Shared Data Channel (UL-SDCH) and plurality of PHY channels. The PHY channels comprise a set of DL channels and UL channels.

The DL PHY channels comprises Common Pilot Channel (CPICH); Synchronization Channel (SCH); Common Control Channel (CCCH); Shared DL Control Channel (SDCCH); Multicast Control Channel (MCCH); Shared UL Assignment Channel (SUACH); Acknowledgement Channel (ACKCH); DL Physical Shared Data Channel (DL-PSDCH); UL Power Control Channel (UPCCH); Paging Indicator Channel (PICH); and Load Indicator Channel (LICH).

The UL PHY Channels comprises Physical Random Access Channel (PRACH); Channel Quality Indicator Channel (CQICH); Acknowledgement Channel (ACKCH); Antenna Subset Indicator Channel (ASICH); Shared Request Channel (SREQCH); UL Physical Shared Data Channel (UL-PSDCH); and Broadband Pilot Channel (BPICH).

The Primary SCH enables synchronization of chip, slot, and symbol and is comprised of 256 chips that are the same in all cells. The secondary SCH provides frame synchronization and code group (i.e., one of 64) and is a 15-code sequence of secondary synchronization codes. There are 64 S-SCH sequences corresponding to the 64 scrambling code groups. The 256 chips are different for different cells and slot intervals. The CPICH is one of eight scrambling codes used to find the primary scrambling code. The PCCPCH (Primary Common Control Physical Channel) is for super frame synchronization and BCCH information that is a fixed 30 kbps channel at a 27 kbps rate with a spreading factor256. The SCCPCH (Secondary Common Control Physical Channel) carries FACH and PCH channels at a variable bit rate.

InFIG. 9, an apparatus900provides for opportunistic data forwarding in a wireless network by comprising means902for receiving wireless communication between a transmitting node and a receiving node comprising packet data units (PDUs). Means904are provided for receiving a communication at a supporting node from the receiving node to the transmitting node indicating a failure to receive a PDU. Means906are provided for transmitting the PDU that was indicated to have failed to the receiving node from the supporting node.

InFIG. 10, an apparatus1000provides for opportunistic data forwarding in a wireless network by comprising means1002for receiving wireless communication from a transmitting node comprising packet data units (PDUs). Means1004are provided for determining a failure to receive a PDU. Means1006are provided for transmitting a communication to the transmitting node indicating a failure to receive a PDU. Means1008are provided for receiving the PDU from a supporting node responding to the communication to the transmitting node.

What has been described above includes examples of the various aspects. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the various aspects, but one of ordinary skill in the art may recognize that many further combinations and permutations are possible. Accordingly, the subject specification intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.

In particular and in regard to the various functions performed by the above described components, devices, circuits, systems and the like, the terms (including a reference to a “means”) used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., a functional equivalent), even though not structurally equivalent to the disclosed structure, which performs the function in the herein illustrated exemplary aspects. In this regard, it will also be recognized that the various aspects include a system as well as a computer-readable medium having computer-executable instructions for performing the acts or events of the various methods.

In addition, while a particular feature may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. To the extent that the terms “includes,” and “including” and variants thereof are used in either the detailed description or the claims, these terms are intended to be inclusive in a manner similar to the term “comprising.” Furthermore, the term “or” as used in either the detailed description of the claims is meant to be a “non-exclusive or”.

Furthermore, as will be appreciated, various portions of the disclosed systems and methods may include or consist of artificial intelligence, machine learning, or knowledge or rule based components, sub-components, processes, means, methodologies, or mechanisms (e.g., support vector machines, neural networks, expert systems, Bayesian belief networks, fuzzy logic, data fusion engines, classifiers . . . ). Such components, inter alia, can automate certain mechanisms or processes performed thereby to make portions of the systems and methods more adaptive as well as efficient and intelligent. By way of example and not limitation, opportunistic data forwarding can be trained to recognize data communications that require assistance in order to avoid expiration and reduction in quality of service. In addition, a particular node can recognize which node is best situated to serve as supporting node. In another example, an access point or administrator node can optimize detection of a situation warranting setting up an intermediate node in a multi-hop path and optimize selection of the best situated node.

In view of the exemplary systems described supra, methodologies that may be implemented in accordance with the disclosed subject matter have been described with reference to several flow diagrams. While for purposes of simplicity of explanation, the methodologies are shown and described as a series of blocks, it is to be understood and appreciated that the claimed subject matter is not limited by the order of the blocks, as some blocks may occur in different orders or concurrently with other blocks from what is depicted and described herein. Moreover, not all illustrated blocks may be required to implement the methodologies described herein. Additionally, it should be further appreciated that the methodologies disclosed herein are capable of being stored on an article of manufacture to facilitate transporting and transferring such methodologies to computers. The term article of manufacture, as used herein, is intended to encompass a computer program accessible from any computer-readable device, carrier, or media.