一种复数球形译码算法的仿真

球形译码算法作为实现最大似然检测的一种有效快速算法受到了学者们的广泛关注。在通信理论中经常使用到复数信号模型,但目前尚未有文献给出在该模型下明晰的算法流程。利用信号星座图的几何特点,推导了一种保持原信号维数的复数球形译码算法;考虑到算法中涉及对整数环的特殊处理,给出了清晰的算法流程。该流程适用于各种复数矩阵信道模型与典型二维信号星座图,为复数模型下球形译码算法的研究提供了一个有效的仿真平台。

Low complexity power control approach based on MMSE detection for V-BLAST

A low complexity Per-Antenna Power Control （PAPC） approach based on Minimum Mean Squared Error （MMSE） detection for V-BLAST is proposed in this paper. The PAPC approach is developed for minimizing the Bit Error Rate （BER） averaged over all substreams when the data throughput and the total transmit power keep constant over time. Simulation results show that the Power-controlled V-BLAST （P-BLAST） outperforms the conventional V-BLAST in terms of BER performance with MMSE detector, especially in presence of high spatial correlation between antennas. However, the additional complexity for P-BLAST is not high. When MMSE detector is adopted, the P-BLAST can achieve a comparable BER performance to that of conventional V-BLAST with Maximum Likelihood （ML） detector but with low complexity.

An antenna selection algorithm for spatial multiplexing systems in BLAST receiver

In this paper, the antenna selection problem for spatial multiplexing systems in a BLAST receiver is investigated. In order to search the optimal antenna subset, a selection criterion is proposed, which is able to obtain the largest minimum post-detection SNR. The number of required antennas is deduced, which is determined by the system performance requirement for the existing RF chains. Simulation result shows that the optimal subset in a BLAST receiver has higher minimum sub-channel SNR than that in a ZF receiver. Computation of system performance can be fitted to a simple function, and it is simpler for the proposed algorithm to compute the required antenna number.

Symbols detection for frequency-selective V-BLAST OFDM systems

As the combining form of the orthogonal frequency-division multiplexing (OFDM) technique and the vertical Bell Labs layered space-time (V-BLAST) architecture, the V-BLAST OFDM system can better meet the demand of next-generation (NextG) broadband mobile wireless multimedia communications. The symbols detection problem of the V-BLAST OFDM system is investigated under the frequency-selective fading environment. The joint space-frequency demultiplexing operation is proposed in the V-BLAST OFDM system. Successively, one novel half-rate rotational invariance joint space-frequency coding scheme for the V-BLAST OFDM system is proposed. By elegantly exploiting the above rotational invariance property, we derive one direct symbols detection scheme without knowing channels state information (CSI) for the frequency-selective V-BLAST OFDM system. Extensive simulation results demonstrate the validity of the novel half-rate rotational invariance joint space-frequency coding scheme and the performance of the direct symbols detection scheme.

Successive interference cancellation (SIC) in V-BLAST systems with asynchronous transmission mode

The V-BLAST system with asynchronous transmission mode first proposed by Shao can achieve full diversity only by using a simple linear detection scheme under zero forcing （ZF） criterion; therefore it gives a reasonable tradeoff between complexity and performance. In this paper, we propose two types of successive interference cancellation （SIC） detection schemes for the asynchronous V-BLAST system, one is characterized by applying Mr successive interference cancellators before a maximal ratio combiner （where Mr is the number of receive antennas）, and the other has a maximal ratio combiner before a successive interference cancellator. Since Type Ⅰ consumes more energy of the previously detected signals to recover a signal, Type Ⅱ can offer a better performance and simulations demonstrate its validity.