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Hybrid automatic repeat request-based self-adapting relay and velocity selection method

A hybrid automatic retransmission and rate selection technology, which is applied in the transmission system, digital transmission system, error prevention/detection using the return channel, etc., can solve the problem of small throughput, achieve good performance, improve system performance, and track well The effect of channel characteristics

Inactive Publication Date: 2012-12-26
UNIV OF SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to propose a hybrid automatic repeat request (HARQ) based adaptive relay and rate selection method to maximize the throughput of the system to solve the problem of poor throughput when a single relay is used for a fixed transmission rate in cooperative communication. small problem

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  • Hybrid automatic repeat request-based self-adapting relay and velocity selection method
  • Hybrid automatic repeat request-based self-adapting relay and velocity selection method
  • Hybrid automatic repeat request-based self-adapting relay and velocity selection method

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Experimental program
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Embodiment 1

[0022] figure 1 A schematic diagram of a mobile communication system using the downlink cooperative transmission of the present invention in a two-hop multi-relay network without a direct path between the source node and the destination node is given. figure 2 It is a flowchart of the operation of adaptive relay and rate selection in the present invention. The base station (source node) S sends data to the user (destination node) D, and there are M idle users R in the cell 1 , R 2 ... R i ,...,R M Can be used as a relay node. This example is in figure 1 The cooperative communication system shown in the figure 2 The shown operation process of adaptive relay and rate selection of the present invention is:

[0023] (1) Before sending data, use the estimation method based on the training sequence to estimate the channel between the source node and all relay nodes, and feed back the channel parameters to the source node. The source node determines the transmission rate of...

Embodiment 2

[0064] Example 2: Performance Simulation

[0065] image 3 Given the signal-to-noise ratio SNR=10dB, the maximum time delay T=6, according to the throughput formula (9) obtained at the number of relays N=8, N=4, N=2, N=1 throughput R and Schematic diagram of the relationship between transmission rate r. from image 3 It can be seen that when N is constant, the throughput R is a convex function of the transmission rate r, and there is a maximum point, that is, figure 2 The r to be found in the second step opt (N). When the transmission rate r is small, the throughput R increases with r, which means that the relay node-destination node channel allows a faster transmission rate. when r>r opt (N), the number of retransmissions and the probability of interruption P out (T) is getting bigger and bigger, making the throughput R smaller and smaller. Under the same transmission rate, N=8 throughput A8>N=4 throughput A4>N=2 throughput A2>N=1 throughput A1, as N increases, R inc...

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Abstract

The invention discloses a hybrid automatic repeat request-based self-adapting relay and velocity selection method, which is characterized by selecting relay nodes for participating in the cooperation in the transmission and proper transmission velocity based on the throughput maximization criterion of the hybrid automatic repeat request policy according to a channel parameter between a source node and a relay node, wherein the selected multiple relay nodes cooperatively send data to a destination node; and if the data is retransmitted due to error, the relay nodes retransmit the data to the destination node. The method mainly comprises the following steps: (1) estimating a channel parameter between the source node and the relay node; (2) calculating the optimal transmission velocity and corresponding throughput under the number of all possibly selected relay nodes; (3) taking the scheme with the maximum throughput as the selection result; and (4) sending the data to the relay node by the source node, then cooperatively sending the data to the destination node by the selected relay node, and retransmitting the data when error occurs. When the method is used, the throughput can be maximized and the system performance is improved.

Description

technical field [0001] The invention belongs to the technical field of cooperative communication in wireless communication, and in particular relates to a hybrid automatic repeat request (HARQ)-based adaptive relay and rate selection method. Background technique [0002] Cooperative diversity technology can effectively provide space diversity without multi-antenna, and resist time-varying fading of wireless channels. In a cooperative communication system, each mobile terminal has one or more partners, which are called relay nodes. Due to the broadcast characteristics of the wireless channel, the relay nodes can receive the data sent by the source node at a low cost and forward it to the The destination node thus obtains diversity gain. The relay node can forward the data received from the source node to the destination node using a variety of forwarding methods including decoding forward (DF), amplification forward (AF) or compression forward (CF), and the number of relay n...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L1/18H04L1/16H04L1/00
Inventor 赵宇峰李辉
Owner UNIV OF SCI & TECH OF CHINA