摘要
针对多用户多输入单输出(Multiple input single output,MISO)系统的用户选择与信道估计问题,引入基于用户分布式自选择的信道接入策略,设计一种新的结合该策略的时分双分复用(Time division duplex,TDD)模式数据传输帧结构。利用用户活跃模式自然稀疏性和信道冲激响应时延域稀疏性,将基站接收上行随机导频序列建模为块稀疏线性模型。基于凸松弛的l2/l1模型提出一种快速的块稀疏重构算法求解问题模型。算法首先对目标函数进行变量分裂,然后利用交替方向法对各变量进行交替更新,直至满足收敛条件。交替更新中,对于无法获得闭式解的信号变量项,采取块坐标下降法求解。计算机仿真表明,与块正交匹配追踪和块压缩采样匹配追踪比较,新算法能够在保持高重构精度的前提下获得更快的计算速度。
To solve the user selection and channel estimation problem in multi-user MISO system, a new data transmission frame structure combined with the decentralized user self-selecting strategy in TDD mode is designed. Then, the base station receiving uplink random pilot sequence signatured with the user identity is built as a block sparse linear model based on the natural signal sparsity from usersr low active degree and the channel impulse response sparsity in delay-spread domain. In addtion, to resolve such an objective optimization problem, an efficient block-sparse signal recovery algorithm is proposed based on lz/ll reconstruction model. In the novel algorithm, the objective function is transformed through variable spli^tting and four variables are alternately updated in the framework of alternating direction method （ADM） until the prespecified convergence criterion is satisfied. During the alternate updating procedure, Aiming at unobtainable closed form solution of the signal variable item, the block coordinate descent （BCD） method is utilized to acquire an iterative solution. Simulation results demonstrate that the pro- posed method can achieve higher computational efficiency and the better estimation accuracy compared with two state-of-art fast algorithms, such as block orthogonal matching pursuit （Block OMP） and block compressive sampling matching pursuit （Block CoSaMP）.
出处
《数据采集与处理》
CSCD
北大核心
2015年第3期552-563,共12页
Journal of Data Acquisition and Processing
基金
国家自然科学基金(61272333)资助项目
安徽省自然科学基金(1208085MF94)资助项目
关键词
块稀疏信号重构
分布式自选择
随机身份标识序列
交替方向法
块坐标下降法
block sparse signal recovery
decentralized self select
random identity signature sequences
alternating direction method
block coordinate descent method
