JP5704710B2 - Mechanisms for relay operation in disrupted wireless networks - Google Patents

Description

  The present invention relates to wireless communications, and more particularly to a medium access control (MAC) layer mechanism that increases reliability in disrupted wireless networks.

  Every day, countless incidents related to public safety, such as traffic accidents, disasters, and crime investigations, occur all over the world. Due to the widespread use of advanced digital devices, police and rescue personnel will receive a lot of attention if the network supports live video streaming even when the network is disrupted. As a result, it is desirable for this public safety network to exhibit high reliability characteristics. This desirable feature is aimed at obtaining higher reliability and efficiency than is obtained individually, as each wireless node is secured by coordinated communication supporting each other during information distribution. This support is realized by a relay operation.

  In the present disclosure, the inventive relay mechanism is implemented at the MAC layer. Traditionally, in the context of cognitive radio networks, there are two ways of cooperative relay strategies: decoding and forwarding and amplification and forwarding. For decoding and forwarding, the transmitter sends a data frame to its repeater in odd time slots. The repeater decodes the data and forwards it to the receiver in the next even time slot. The receiver can decode the frame if the frame is not lost or corrupted on both links. In amplification and forwarding, the repeater amplifies the received signal and forwards it to the receiver in the same time slot. The repeater receives data from the transmitter using a transceiver that operates on one or more idle channels and simultaneously transfers the data to the receiver using another transceiver that operates on one or more different idle channels. If the SNR of the receiver is greater than or equal to the threshold, the data frame can be decoded. In the following literature, researchers have found that each of these strategies works better with a range of parameters, and that the two strategies are not inferior (D. Hu, S. Mao, ｀ ｀ Cooperative Relay in Cognitive). Radio Networks: Decode-and-Forward or Amplify-and-Forward, “in the processing of IEEE Globecom 2010”.

  In IEEE 802.16m, decoding and forwarding are used for the relay function. In order to maintain backward compatibility, the present invention uses this strategy.

  D. Hu, S .; Mao, “Cooperative Relay in Cognitive Radio Networks: Decode-and-Forward or Amplify-and-Forward,” IEEE Globecom 2010 Minutes.

  Accordingly, the present invention is directed to a MAC layer mechanism that provides a relay function that ensures continuous network connectivity in disrupted wireless networks.

  Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the specification, or may be taught by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings.

To achieve these and / or other objectives, as described broadly in detail, the present invention provides relay assistance for multi-mode operation in networks considered in the IEEE 802.16n GRIDMAN standard consisting of: Provides the mechanisms implemented at the MAC layer:
(A) Relay support between base stations (BS);
(B) Relay support between mobile stations (MS);
(C) Relay support between the mobile station and the base station.

  It is understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are for the purpose of further illustrating the claimed invention.

FIG. 1 shows a message flow between base stations with support of a relay function. FIG. 2 shows a message flow between mobile stations operating as relays. FIG. 3 shows a flowchart of the relay mechanism.

  1. Communication from BS to BS

  In FIG. 1, a highly reliable base station (HR-BS) sends a BS_Relay_REQ request to an adjacent BS / MS for a relay support request. If more than one acknowledgment BS_Relay_ACK / MS_Relay_ACK is received, the HR-BS decides which offer it will receive (BS_Relay_ACK has higher priority). A BS_Relay_Confirm message is sent out.

Upon receipt of the confirmation, the responding BS (MS) performs the following two tasks.
1. Update this status.
2. Create a superframe header (SFH) and HR-MAP for the next station.
3. Send HR-Preamble, SFH and HR-MAP for the next station.

  2. Communication from MS to MS (MS is relay mode)

  In FIG. 2, a highly reliable mobile station (HR-MS) sends an MS_Relay_REQ request to an adjacent station for a relay support request. If more than one acknowledgment BS_Relay_ACK / MS_Relay_ACK is received, the HR-MS decides which offer to receive (BS_Relay_ACK has a higher priority). Then, an MS-Relay-Confirm message is transmitted.

Upon receipt of the confirmation, the responding BS performs the following two tasks.
1. Update this status.
2. Create a superframe header (SFH) and HR-MAP for the next station.
3. Send HR-Preamble, SFH and HR-MAP for the next station.

Upon receipt of the confirmation, the responding MS performs the following tasks:
1. Notify BS of role change.
2. Upon receiving confirmation ACK_RM from the BS, the responding MS changes the role.
3. It then creates a superframe header (SFH) and HR-MAP for the next station.
4). Send HR preamble, SFH, HR-MAP for the next station.

Claims (2)

a) Relay support between base stations (BS);
b) Relay support between mobile stations (MS);
c) A wireless communication method for providing relay support between a mobile station and a base station ,
Relay support between base stations
a) The initial BS sends a request message to the neighboring station;
b) the initial BS determines which response to acknowledge when receiving multiple messages;
c) sending a confirmation message after the initial BS is determined;
d) The response BS is
i) status updates ;
ii) creation of SFH and HR-MAP for the next station;
consists iii) and HR preamble for the next station, and SFH, transmission and HR-MAP, and by performing,
Relay support between mobile stations and relay support between mobile stations and base stations
a) Initially the MS sends a request message to the neighboring station;
b) initially determining which response to acknowledge when receiving multiple messages;
c) sending a confirmation message after the initial MS is determined;
d) If a response BS is selected,
i) status updates;
ii) creation of SFH and HR-MAP for the next station;
and HR preamble of for iii) the next station, and the SFH, transmission and HR-MAP, was carried out,
e) When the response MS is selected,
i) Notifying the BS about the role change ;
ii) when receiving a confirmation ACK_RM from the BS, updating the status ;
iii) creation of SFH and HR-MAP for the next station;
iv) and HR preamble for the next station, consisting of a SFH, transmission and HR-MAP, and carrying out the radio communication method characterized by. The wireless communication method according to claim 1, wherein the wireless communication method is implemented in a medium access control (MAC) layer.

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