Self-adaptation cooperative transmission method in cellular mobile communication D2D system

Abstract

The invention discloses a self-adaptation cooperative transmission method in a cellular mobile communication D2D system. The method is carried out in the following steps that firstly, Doppler frequency offset of users participating in cooperation in a cell is estimated, and a channel delay related coefficient is obtained; according to a scheduling algorithm, cell users and D2D users participating in cooperative transmission are determined, and a base station determines a transmission mode which will be used in cooperation; the users estimate channel information of themselves and feed the information back to the base station; at last, data transmission is carried out in a pre-coding scheme in a selected mode. The method can be effectively used in actual scenes; under the control of a core network, frequency resources of the cell users in the cellular mobile communication system are shared with users on the border of the cell so that data transmission from equipment to equipment can be carried out, cost of cell transmission capacity of the cellular communication system is reduced a little, the reachable transmission rate of the users on the border of the cell is improved greatly and accordingly an average frequency spectrum utilization rate in the cell is improved.

Description

technical field [0001] The invention belongs to the field of cooperative transmission in a mobile communication multiple-input multiple-output (MIMO) system, and relates to a cooperative transmission method in a cellular mobile communication system. Background technique [0002] In the cellular mobile communication system, users at the edge of the cell face the difficulties of low useful signal power and high interference signal power, and cannot effectively obtain high data transmission rates. In recent years, some scholars have continuously proposed that device-to-device D2D) to establish a direct communication link to effectively increase the data rate of cell edge users. In the existing cellular mobile communication environment, this D2D technology enables users located at the cell edge to directly establish links with adjacent terminals for data transmission by sharing the frequency resources of other users in the cell. Since the distance between the two users of D2D c...

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Problems solved by technology

This scheme will lead to a certain quantization error between the system channel information obtained by the base station and the real channel information, and the size of this quantization error is determined by the capacity of the feedback link

In addition, when the feedback mechanism is used, there is also the problem of information delay caused by the feedback link, that is, the feedback information obtained by the base station is not the channel information at the current moment, but the channel information before a certain delay

Under the influence of the above factors, the downlink information obtained by the base station does not completely match the real channel information, resulting in a significant decline in the performance of the adaptive transmission scheme based on ideal channel information. Adaptive switching between MR and IC cooperative modes under the condition of channel information

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