Self-adaptive method for carrying out multiple input/output OFDM link through capacity

A link adaptation, multi-input technology, applied in multi-frequency code systems, diversity/multi-antenna systems, etc., to achieve the effect of improving system data throughput and strong use value

Inactive Publication Date: 2007-02-21
TSINGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the inherent multipath propagation and Doppler effect of wireless signals, MIMO-OFDM systems will still be affected and constrained by the time and frequency selectivity of mobile wireless channels

Method used

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  • Self-adaptive method for carrying out multiple input/output OFDM link through capacity
  • Self-adaptive method for carrying out multiple input/output OFDM link through capacity
  • Self-adaptive method for carrying out multiple input/output OFDM link through capacity

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Embodiment Construction

[0036] Below in conjunction with accompanying drawing and example, effect of the present invention is described in detail:

[0037] In this embodiment, the MIMO-OFDM system is used for transmitting and receiving, each OFDM symbol has 2048 subcarriers, the number of transmitting antennas Nt=4, the number of receiving antennas Nr=4, there are Q=14 selectable modes, and the data throughput rate is There are three stalls of 100M, 50M and 25M, and the thresholds in step (5) are set to 10.2 and 5.2. Send the block diagram as figure 1Shown: When using the qth sending mode, set N m (q) Independent code streams after 16QAM or QPSK modulation are assigned the same power P i , pass it through the originating rotation matrix F(q) to get the sequence A j (q), for each subflow sequence A j After performing OFDM modulation and encoding respectively in N t sent out on antennas, where i=l, 2...N m (q); j=1, 2...Nt, q=l, 2..Q. Receive block diagram as figure 2 shown.

[0038] Mode MOD...

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Abstract

The invention features the following points: at a preset modulation mode, for different transmission mode, calculating different equivalent SNR for each substream; then according to the SNR-instantaneous capacity curve, acquiring the instantaneous channel capacity on the subcarrier on each subcarrier wave; then according to the instantaneous channel capacity, figuring out the instantaneous average value of the current channel capacity on different transmission mode; according the average value, figuring out the channel capacity running average value; the corresponding transmission mode is selected by whether or not the running average value satisfies a preset lowest threshold.

Description

technical field [0001] The invention relates to a method for link self-adaptation in a multi-transmit and multi-receive orthogonal frequency division multiplexing MIMO-OFDM system. Background technique [0002] With the increasing bandwidth requirement in wireless communication, Orthogonal Frequency Division Multiplexing (OFDM) multi-carrier transmission system is attracting a lot of attention in recent years. [0003] The OFDM system has many advantages such as high spectrum utilization rate, less affected by ISI and narrowband interference, and easy implementation of orthogonal modulation / demodulation operations. The introduction of multi-antenna technology has effectively improved system capacity and performance. However, due to the inherent multipath propagation and Doppler effect of wireless signals, MIMO-OFDM systems will still be affected and constrained by the time and frequency selectivity of mobile wireless channels. [0004] Under certain wireless link quality, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04B7/02
Inventor 周世东高群毅张秀军王京许希斌李云洲
Owner TSINGHUA UNIV
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