矿井巷道时频编码协作MC-CDMA伙伴选择与子载波分配

针对矿井巷道的带状结构特点,提出一种基于基站瞬时接收信噪比和用户位置的矿井巷道时频编码协作MC-CDMA无线传输协作伙伴选择策略,由基站为信道状况较差的用户选择协作伙伴。由于相邻子载波信道的相关性较大,为扩频支路分配相邻的子载波,可能会导致矿井MCCDMA一些扩频支路传输质量偏低,影响无线传输的性能。为此,提出了一种为矿井MC-CDMA每个扩频支路按固定间隔分配离散子载波的次优子载波轮转分配算法。在次优分配方案中,不考虑各子载波瞬时信道增益,可简化按用户各子载波瞬时信道状况分配子载波的最优子载波分配算法。仿真结果表明,采用所提出的协作伙伴选择策略以及子载波分配算法显著提高了矿井巷道时频编码协作MC-CDMA无线传输用户的信道容量和误码率性能,增强了矿井巷道时频编码协作MC-CDMA无线传输系统信道容量的鲁棒性和通信的可靠性。

Partner selection and subcarrier allocation of time-frequency coded-cooperation MC-CDMA in mine tunnel

In terms of the banded structure of underground mine roadways，a cooperative partner selection protocol was proposed for time-frequency coded cooperation MC-CDMA wireless transmission，which is based on the instantaneous signal to noise ratio (SNR) received by base station (BS) and the location of users，and the cooperative partner selected by BS.Due to the channel relativity for neighboring subcarrier，it may cause reduced transmission quality for some spread branches of mine MC-CDMA to allocate subcarrier contiguously，which will affect the performance of wireless transmission.Therefore，a suboptimal subcarrier allocation scheme called subcarrier rotary allocation was proposed，which allocates discrete subcarrier to spread branches with fixed interval.Since the subcarrier’s instantaneous channel condition was not taken into account in the suboptimum scheme，it was much simpler than the optimal protocol which allocates subcarrier according to the instantaneous channel condition of subcarrier.Simulation results show that the channel capacity and bit error rate (BER) performance of users are improved significantly with the proposed cooperative partner selection protocol and the subcarrier allocation scheme for the time-frequency coded cooperation MC-CDMA wireless transmission.In this way，the robustness of channel capacity and the reliability of underground wireless communication are enhanced significantly.