能耗感知的MIMO天线配置模式选择算法

多入多出MIMO (multiple input multiple output)利用多天线技术可以在同一信道内并发传输多路数据，实现空间复用增益和空间分集增益，从而提升系统吞吐量、传输范围和可靠性，但MIMO所采用的多天线技术会大幅增加通信终端的能耗成本。能耗是智能终端的关键性能指标，也是制约MIMO技术能否在智能终端上推广使用的重要因素。针对这一问题，研究了IEEE 802.11n 的MIMO发送端能耗问题，提出了一种能耗感知的MIMO天线配置模式选择算法。该算法以单位比特能耗为优化目标，根据缓冲区待发送数据帧的数量，动态调整MIMO天线配置模式。缓冲区待发送数据帧的数量超过上限阈值时，发送端调整天线配置模式，并根据待发送帧大小和历史统计信息预测和激活能耗最优的天线数量；低于下限阈值时，发送端关闭多天线，采用单天线进行数据传输。基于真实实验数据的数值分析结果表明，该算法能够充分利用睡眠状态优化MIMO发送能耗，有效提升单位比特能耗。

Power-aware algorithm of MIMO antenna configuration mode selecting

MIMO (multiple input multiple output) utilizes the technology of multiple antennas to concurrently transmit multiple data streams in one channel for spatial multiplexing gain and spatial diversity gain. MIMO can not only improve system throughput, transmission range and reliability, but also bring out the new issue that multiple antennas dramatically increase energy overhead of terminal. Energy is a key performance index of smart terminal, and is also an important factor for the prevalence of MIMO in it. The issue of MIMO sender was studied, and a power aware algorithm of MIMO antenna configuration mode selecting proposed. It uses energy per bit as optimization object, and dynamically adjusts the number of active antennas according to the buffer size. The MIMO sender uses frame size and statistical information to calculate the optimal antenna number and activates them when the buffer size is bigger than upper threshold. And the sender turns down multiple antennas and keeps one working when the buffer size is smaller than the lower threshold. The trace driven analysis results show that the proposed algorithm can optimize energy per bit of the sender efficiently by utilizing sleep status.