Performance Analysis of Two-Stage Signal Processing Structure in Antenna Array

Computation afford of adaptive antenna technology is the key factor limited its applications. This paper presented a new two-stage structure to solve this problem. By dividing array antennas into two group, two–stage structure can reduce computation afford with the same system performance of one-stage structure as the traditional adaptive antenna technology does. Algorithm and criterion in each stage can be selected independently according to the applications situations. Theoretical analyses of system performance in two-stage and one-stage structures are presented, and computation simulations are performed using RLS algorithm. Due to the low-complexity and low-computation, more antennas can be used to improve performance. For diversity receiving, it can help to improve SNR and less computation afford is obtained with the same performance as the traditional processing structure. The presented two-stage structure can be generalized easily to multiple–stage structure. Introduction In wireless communications, how to remove the influence from co-channel interference (CCI), multi-address interference (MAI) and multi-path fading has become the key aspect when system performance is analyzed. Adaptive antenna technology employs digital signal processing technologies to improve SINR through adjusting beam direction of antenna array. Because there are more users and real time need in adaptive antenna system, the ability of rapid computation is necessary for adaptive antenna system. In fact, digital processing technologies have been the key factor that limits the applications of adaptive antenna system. Until now, a lot of documents have adopted antenna diversity to solve the computation afford. After processed by antenna diversities, such as selection combining, equal-gain combing and maximal-ration combining, array signals can be processed with adaptive algorithms (for example MLSE and CMA). System Model The presented algorithm is shown in Fig.1. Digital signal processing can be performed in base band or mid-frequency band as usually. Two stage processing algorithm, however, is employing. Through A/D transformation, signals on the array elements are divided into two groups, with signals on each group being processed independently and being output. The output signals on each group of antennas are input to process in DSP, general CPU or ASIC/FPGA. With processing signals into two-stage, we can select different algorithms, even different criterions, according to applications needs and signals properties and signals quality and convergence speed are to be improved. At the same time, due to dividing, the number of antennas in each group is less, and the computation afford will be reduced. If RLS algorithm is used, computation afford is proportionate to square of array elements’ number. 7th International Conference on Mechatronics, Computer and Education Informationization (MCEI 2017) Copyright © 2017, the Authors. Published by Atlantis Press. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Advances in Computer Science Research, volume 75