KR200413131Y1 - Peer-to-peer wireless communication systeam - Google Patents

Abstract

Initiate peer-to-peer communication using direct link setup (DLS). A mobile station (STA) establishes a direct communication link with another STA by sending a message requesting DLS to an access point (AP) (ie, a centralized controller). The AP may accept or reject the DLS request based on the channel measurement. If the DLS request is accepted, the DLS is established such that the STAs may communicate directly with each other. The established DLS connection may be released by sending a message containing a DLS release request to one of the STAs or based on channel measurement. The system may be an ad hoc network including a plurality of STAs without an AP, and after each STA maintains a database of one-hop and two-hop STAs and notifies the neighbor STA of the purpose of establishing a direct communication link, Establish a direct link with another STA.

Description

Peer-to-peer wireless communication system {PEER-TO-PEER WIRELESS COMMUNICATION SYSTEAM}

1 is an exemplary block diagram of a wireless communication system including a plurality of QSTAs and QAPs in accordance with the present invention.

2 is a block diagram of an ad hoc network including a plurality of STAs that support peer-to-peer communication in accordance with the present invention.

3 is a block diagram of a network including a plurality of STAs and APs for supporting peer-to-peer communication according to the present invention.

The present invention provides a wireless communication system including a plurality of radio stations (STA) and an access point (AT) (i.e., a centralized controller), and a wireless communication system (i.e., an ad hoc (i.e., a plurality of STAs without a centralized controller). Ad hoc network). More specifically, the present invention relates to a system and method for establishing data transmission between STAs using direct link setup (DLS).

In general, STAs do not allow direct transmission of data packets to other STAs in a Basic Service Set (BSS), but must always rely on the AP for delivery of data packets. However, a STA with quality of service (QoS) functionality (i.e., QSTA) may transmit data packets directly to other QSTAs by establishing data transmission using DLS. The IEEE 802.11e standard relates to support of QoS features such as service differentiation, block acknowledgment notification (ACK), and DLS. STAs that support these IEEE 802.11e features are referred to as QSTAs. Similarly, APs that support these IEEE 802.11e features are referred to as QAPs. The need for DLS is due to the fact that the intended destination STA may be in a power saving mode, whereby only the destination QSTA may be activated (i.e., awakened) by an AP with QoS (i.e., QAP). Required. The DLS exchanges rate sets and other information between a transmitter in one QSTA and a receiver in another QSTA. The DLS message can be used to attach a safety information element (IE).

The present invention relates to a peer-to-peer communication system using DLS. A mobile station (STA) establishes a direct communication link with another STA by sending a message requesting DLS to an access point (AP) (ie, a centralized controller). The AP may accept or reject the DLS request based on the channel measurement. If the DLS request is accepted, the DLS is established so that the STAs can communicate directly with each other. The established DLS connection may be released by the AP sending a message that includes a DLS release request to one of the STAs, or based on channel measurement. The system may be an ad hoc network including a plurality of STAs without an AP, and each STA maintains a database of one-hop and two-hop, where it establishes a direct communication link. After notifying the neighbor STA may establish a direct link to another STA.

Hereinafter, the term “STA” or “QSTA” includes but is not limited to a wireless transmit / receive unit (WTRU), user equipment, mobile station, fixed or mobile subscriber unit, pager, or any other kind of device operable in a wireless environment. no. The term "AP" or "QAP", referred to below, includes, but is not limited to, a base station, a Node B, a site controller, a centralized controller, or any other kind of apparatus for interfacing in a wireless environment.

Features of the present invention may be integrated into integrated circuits (ICs) or may be configured in circuits that include multiple interconnect components.

The present invention facilitates the establishment of data transmission between QSTAs in a peer-to-peer wireless communication system such as a wireless local area network (WLAN) or a wireless wide area network (WWAN) using DLS. The present invention further performs a signaling procedure for performing data transmission with Hybrid Coordination Function Controlled Channel Access (HCCA) or Enhanced Distributed Channel Access (EDCA), DLS establishment, and DLS release.

Further details regarding DLS, HCCA and EDCA are disclosed in US patent application Ser. No. 11 / 199,446, entitled "Method and System for Controlling Access to a Wireless Communication Medium" by Sudheer A. Grandhi, et al. The whole is incorporated by reference.

1 is an exemplary block diagram of a wireless communication system 100 that includes a plurality of QSTAs 12a and 12b and a QAP 10. Similar to the conventional wireless communication system, the QSTA 12a is intended for data packet exchange directly with the QSTA 12b. QSTA 12a performs DLS by including the DLS request frame in message 102 sent by QSTA 12a to QAP 10. The message 102 may include a rate set, performance information of the QSTA 12a, a MAC (Media Access Control) address of the QSTA 12a, 12b, or other necessary information. If QSTA 12b is associated with QAP 10 in a Basic Service Set (BSS) with a means of allowing a policy to allow direct data transfer to occur between QSTAs, QAP 10 may request DLS in message 104. The request frame is sent to the QSTA 12b. If QSTA 12b accepts the DLS request frame, QSTA 12b includes the DLS response frame in message 106 sent to QAP 10 by QSTA 12b containing a rate set. do. QAP 10 includes a DLS response frame in message 108 sent to QSTA 12a. Thereafter, a direct communication link 110 is established between QSTA 12a and QSTA 12b.

According to the present invention, QAP 10 may reject a DLS request received from QSTA 12a due to inadequate channel quality of the signal associated with QSTA 12a, 12b, so that QAP 10 may receive message 104. Will not be able to send to QSTA 12b. The DLS request frame included in the message 102 includes an IE for optimal physical layer (PHY) rate and / or other channel quality information between the QSTAs 12a and 12b. This information may be obtained from a previous transmission between QSTA 12a and QSTA 12b, or by listening to the transmission from QSTA 12b (received by QAP 10 or other QSTAs). May be If this information is not available, QSTA 12a sends a message 102 with an IE set to 0 (ie, null).

If QSTA 12a needs to perform a search for QSTA 12b, QSTA 12a includes a DLS discovery request frame in message 112 sent to QAP 10. If QAP 10 knows QSTA 12b, QAP 10 includes a DLS discovery request frame with associated MAC information in message 114 sent to QSTA 12a. In contrast, QAP 10 includes a DLS discovery request frame and an indication that QSTA 12b cannot be located in message 114. This process is performed before DLS is established.

With reference to FIG. 1, additional messages may be exchanged further before or after DLS is established. QAP 10 may optionally include a DLS measurement request packet in message 116 sent to QSTA 12a to request channel quality measurement. The message 116 may also include information related to the performance of the QSTA 12b to perform channel quality measurements. The performance information includes, but is not limited to, an indication of the type of supported antenna technology, such as multiple antennas and multiple input / output (MIMO), antenna diversity or any other smart antenna technology. QSTA 12a responds to message 116 by including a measurement response packet in message 118 sending to QAP 10. Message 118 may also include channel quality measurement results between QSTA 12a and QSTA 12b. The channel measurement measures received signal strength indication (RSSI) between QSTA 12a and QSTA 12b, channel quality indication (CQI) between QSTA 12a and QSTA 12b, and the interference level at QSTA 12a. It may also include. RSSI is measured at QSTA 12a from QSTA 12b by passive listening to packets sent from QSTA 12b to QAP 10 or other QSTA / STA. Even before DLS is implemented, CQI measurements may be obtained by actively transmitting packets from QSTA 12a to QSTA 12b. The messages 116, 118 may be exchanged before the message 108 is sent by the QAP 10 or during the DLS session in progress.

In a typical wireless communication system, the DLS may be teared down by one of the two QSTAs 12a, 12b. The DLS release process cannot be started by the QAP 110. QSTA 12a, 12b may release DLS due to inactivity or completion of the application. Each QSTA 12a, 12b may include a timer that is reset whenever a packet (a data packet or an acknowledgment notification (ACK) packet) is received from another QSTA 12a, 12b. The timer is used to terminate DLS due to link failure or completion of the application. If no packet is received before the timer expires or before the application completes, the QSTA 12a, 12b starts the DLS release process by including the DLS release packet in the message 120a 120b sent to the QAP 10. do. After the DLS release procedure is completed, all packets transmitted by the QSTAs 12a and 12b are processed by the QAP 10.

 One of QSTA 12a and QSTA 12b may send a DLS release packet to QAP 10. Once the DLS release message 120 is sent by one of the QSTAs 12a and 12b, the QAP 10 will send the DLS release message to the other of the QSTAs 12a and 12b. The DLS release process may be implemented by any access method (eg, allocated resource allocation, managed resource allocation, HCCA or EDCF).

According to the present invention, QAP 10 may initiate DLS release by sending a DLS response message 108 including a DLS release action field to one of QSTA 12a or 12b. The action frame contains a timer information field and the QSTA 12a or 12b must respond by sending a DLS release message to the QAP 10 before the timer expires. This feature is backward compatible with current WLAN standards.

QAP 10 may initiate DLS between two QSTAs 12a and 12b. QAP 10 sends a DLS initiation message to each QSTA 12a, 12b. As long as QAP 10 receives a DLS request message from both QSTA 12a, 12b in response to a DLS initiation message, the QAP 10 may transmit a DLS response message to both QSTA 12a, 12b. . The DLS initiation message is a new message introduced by the present invention to allow the QAP 10 to initiate DLS between two STAs. Alternatively, the DLS request message and the DLS response message may be modified to start DLS from QAP 10 instead of generating a new DLS initiation message.

Data transmission after the DLS is established will be described later. The QSTA may use DLS to perform data transfer using any access mechanism defined in the IEEE 802.11e standard, such as HCCA or EDCF.

The present invention provides several action frame formats for DLS management purposes. Immediately after the category field, the action field distinguishes formats. The action field values associated with each frame format are defined in Table 1.

Action field value meaning 0 DLS request One DLS response 2 DLS off 3-255 Spare

Table 1

Additional action field values are defined according to the present invention. The DLS discovery request frame is for QSTA to send the application requirements to get the MAC address of another QSTA. The DLS discovery response frame is for the QAP to respond back to the MAC address of the requested QSTA. A typical DLS release frame is modified by QAP to add an action field on DLS release. An information field called a timer is included in the DLS release frame. QAP expects QSTA to send a DLS release message to QAP before the timer expires. A typical DLS request frame is modified to include additional elements to transmit the optimal PHY data rate and certain other channel characteristics between two QSTAs. The DLS measurement request frame is for a measurement request from QAP to QSTA. The DLS measurement request frame includes performance information of another QSTA. The DLS Measurement Response frame is for the DLS Measurement Response from QSTA to QAP. The DLS measurement response frame includes measurement information and another QSTA MAC address.

2 is a block diagram of an ad hoc network 200 including a plurality of QSTAs 12a, 12b, 12c, 12d, 12e, 12f for supporting peer-to-peer communication according to another embodiment of the present invention. Each QSTA 12a-12f maintains a database (not shown) of all QSTAs 12a-12f within one hop and two hops. One-hop QSTAs are QSTAs that can hear each other, hereinafter referred to as "neighbors". Two hop QSTAs are QSTAs that cannot be heard directly, but neighbors can listen.

There are two groups of QSTAs that need to be notified when the medium is used, which can listen to transmissions, possibly transmit and interfere with reception. Thus, only the transmitting QSTA and the receiving QSTA need to notify their neighbor QSTAs, respectively. The transmitting QSTA needs to inform its neighbor that the medium is used and that the neighbor cannot receive without interference. The receiving QSTA needs to inform its neighbor that the medium is being used and the neighbor should not be transmitted. This may require some handshaking to implement properly, but this will further increase overall media efficiency.

Neighbor QSTAs send signals to each other to report performance through performance messages. The performance message may be sent as part of the initialization process when the QSTA is powered on. This performance message may be periodic or event-triggered by some active or inactive of any QSTA, or may be a response to an information request signal initiated by one of the QSTAs.

The new QSTA may send a broadcast message to a neighbor requesting an active transmission. The new QSTA may manually scan the channel and then send the indicated packet. In receiving a request, any QSTA in an active session may send information back to the new QSTA. QSTA follows a random back off before responding. Once the new QSTA gets the information, the new QSTA uses this information to optimally allocate resources for the start of a new application.

For example, in the ad hoc network 200 of FIG. 2, the QSTA 12a and the QSTA 12b wish to communicate with each other. Before running the application between QSTA 12a and QSTA 12b, one or both of QSTA 12a and QSTA 12b notifies the neighbor by sending a message 202 about the application. The message 202 may be transmitted as a broadcast or propagated to a two hop QSTA. Alternatively, message 202 may include a packet indicated by a particular QSTA. After notifying the neighboring QSTA of the intended communication, QSTA 12a and QSTA 12b may communicate by exchanging message 204 without interference.

 Information communicated between the QSTAs 12a, 12b includes, but is not limited to, bandwidth requests, identification of transmission and reception QSTAs, frequency bands, preferred modulation modes, sub-carriers, MIMO enable codes, and the like. This information should preferably be communicated during the establishment of the DLS. However, it may be communicated during DLS communications to update certain parameters, such as desired modulation. This information may be resent in response to a request from another QSTA. QSTA may request this information to update their statistics or start a new application.

Some services or applications may take precedence over others and may interfere with other services on demand. An example of this service is Voice over IP (VoIP) for emergency call 911. The instrumentation can be performed by exchanging messages between different transmitting QSTAs to suspend their service, or by exchanging messages to readjust bandwidth, subcarrier, frequency band, and the like.

3 is a block diagram of a network 300 including a plurality of QSTAs 12a-12b and QAP 14 according to the present invention. Similar to the ad hoc network 200 of FIG. 2, each QSTA 12a-12f maintains a database of all QSTAs, where each QSTA 12a-12f can communicate directly and via QAP 14. Can communicate. This QAP 14 may provide a database of QSTA 14 available through the QAP 14.

Each QSTA 12a-12f is connected to a QAP 14. However, all traffic does not necessarily originate from or pass through QAP 14. Thus, two QSTAs may communicate directly with each other without transmitting traffic through the QAP 14. This process may be controlled via distribution control and QAP 14, which is similar to the non-AP case described above with reference to FIG.

In the process controlled by QAP 14, for example, QSTA 12a would like to communicate with QSTA 12b. QSTA 12a sends a message 302 to QAP 14 that includes at least one of a destination ID, request bandwidth, channel information, direct hop to the destination, and the like. Based on the information provided in the message 302, the QAP 14 determines whether to let the two QSTAs 12a, 12b communicate directly or through the QAP 14. The QAP 14 may make this determination based on the signal strength between the two QSTAs 12a and 12b, the current network load, the amount of activity of the QAP 14, and the performance between the two QSTAs 12a and 12b. have. This QAP 14 indicates that it is available to send a message 304 containing allocation information for allocating resources (e.g., specific times, sub-carriers or antennas) for connection based on requirements. Thereafter, a direct communication link 306 is established between QSTA 12a and QSTA 12b.

The allocation information in message 304 is sent to QSTA 12a and QSTA 12b. Other QSTAs 12c-12f may be notified of the direct communication link 306 to let them know the resources they are using. Although they are not intended for use, by broadcasting the message 304 to all QSTAs 12a-12f in these QSTAs 12c-12f, or all QSTAs 12a-12f have QAPs for the message 304 ( 14) can be notified by requesting to be monitored. This may prevent other QSTAs 12a-12f from using the same resource.

Although features and elements of the present invention have been described in particular combinations with the preferred embodiments, each feature or element may be used alone or in various combinations or without other features and elements of the present invention without the other features and elements of the preferred embodiments.

It facilitates the establishment of data transmission between QSTAs of a peer-to-peer wireless communication system such as a wireless local area network (WLAN) or a wireless wide area network (WWAN) using the DLS of the present invention.

Claims (19)

In a wireless communication system, (a) at least one access point (AP), (b) a first station (STA) in communication with the AP, (c) a second STA in communication with the AP, wherein the second STA sends a direct link setup (DLS) request to the AP to establish a direct communication link to the first STA, and the AP Send a DLS request to the first STA, wherein the AP sends a DLS response to the second STA indicating whether to accept the DLS request. The wireless communication system of claim 1, wherein the DLS response is based on a strength of a signal exchanged between the first STA and the second STA. The wireless communication system of claim 1, wherein the DLS response is based on a current load activity amount of the AP. The system of claim 1 wherein the DLS response is based on the capabilities of the first STA and the second STA. The system of claim 1, wherein the DLS response is based on channel quality in which data packets are exchanged between the first STA and the second STA. 6. The system of claim 5 wherein the channel quality is determined by exchanging packets between the first STA and the second STA before DLS is implemented. The wireless communication system of claim 1, wherein the DLS response is based on an interference level of a channel in which data packets are exchanged between the first STA and the second STA. The wireless communication system of claim 1, wherein the DLS request comprises at least one of a rate set, a capability of the first STA, and media access control (MAC) addresses of the first and second STAs. . The AP of claim 1, wherein the AP transmits a measurement request to the second STA to measure a channel condition between the first STA and the second STA, and transmits a response having the measurement result by the second STA. And to determine whether to accept the DLS request based on the measurement result. The method of claim 1, wherein the second STA sends a message to the AP to search for the first STA before the second STA sends the DLS request to the AP, and the second STA sends the message from the AP. The second STA transmits the DLS request to the AP only when receiving the related information of the first STA. The wireless communication system of claim 1, wherein the first STA includes an optimal rate and channel quality information between the first STA and the second STA in the DLS request. 12. The system of claim 11 wherein the information is obtained from a previous transmission between the first STA and the second STA. 12. The system of claim 11 wherein the information is obtained by monitoring a transmission from the second STA. The method of claim 1, wherein the AP is a higher total between the first STA and the second STA by facilitating transmission through the AP instead of allowing direct communication between the first STA and the second STA. Wherein if the workload can be provided, the AP is configured to reject the DLS request. The wireless communication system of claim 1, wherein the AP is configured to reject the DLS request to guarantee communication between the first STA and the second STA. The DLS teardown of claim 1, wherein each of the first STA and the second STA includes a timer, and each of the first STA and the second STA is performed by the AP before the timer expires. Wherein the wireless communication system is configured to start. 17. The system of claim 16 wherein the timer is reset in response to receiving a packet. The wireless communication system of claim 1, wherein the second STA transmits a measurement packet to the first STA and the AP before DLS is executed, thereby improving a data rate and a packet error rate. 19. The system of claim 18 wherein the measurement packet is one of a channel quality indication (CQI), a received signal strength indication (RSSI) or an interference measurement.

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