摘要: |
在时分双工(TDD)多天线系统中,由于上行信道估计误差和上下行传输时延,上下行链路信
道的互易性并不理想。针对非理想互易条件下基于最小均方误差线性接收准则的双流波束赋
形,通过推导其后验信干噪比,得到了容量上界的闭合表达式。数值和仿真结果表明:所得
上界与准确值较为接近;且与理想互易情形相比,非理想互易性对系统的复用增益没有影响
,而只会降低系统的阵列增益。 |
关键词: 双流波束赋形 遍历容量 多入多出 互易性 时分双工 |
DOI:10.3969/j.issn.1001-893X. |
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基金项目:国家科技重大专项资助项目(2009ZX03002-001) |
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Capacity Analysis of Dual Stream Beamforming in TDD Systems with Nonideal Channel Reciprocity |
ZHANG Lei,ZHOU Bao-long,HU Bo,LI Chun-ting |
(1.AlcatelLucent Shanghai Bell Co.,Ltd., Shanghai 201206, China;
2.Department of Electronic Engineering,Fudan University, Shanghai 200433,China) |
Abstract: |
In a time division duplex (TDD) multiple antenna system, the channel r
eciprocity between uplink and downlink is not ideal due to the uplink channel es
timation error and the transmission delay between the uplink and downlink. In th
is paper, we investigate dual stream beamforming in the scenario of nonideal rec
iprocity given minimum mean squared error (MMSE) linear receiver, and derive the
closeform expression of upper bound (UB) on the ergodic capacity by analyzing
the corresponding postSINR (Signal to Interference plus Noise Ratio). The nume
r
ical and simulation results show that the derived capacity UB is close to the ac
curate value, and the nonideal reciprocity only decreases the array gain while d
ose not impact the multiplexing gain. |
Key words: dual stream beamforming ergodic capacity multiple input multiple output (MIMO) reciprocity time division duplex (TDD) |