RLMS algorithm for fixed or adaptive beamforming

Abstract

This paper presents a flexible method of achieving either fixed or self-adaptive antenna beamforming. It involves the use of the array image factor ' d A , which interfaces the Recursive Least Squares (RLS) and Least Mean Squares (LMS) sections in cascade to form the RLMS beamforming algorithm. It is shown that an accurate fixed beam can be obtained by simply setting the elements of ' d A with prescribed values corresponding to the required direction. Moreover, the beam direction can also be made adaptive to automatically track the target signal. In this case, a simple method is described for estimating the element values of ' d A based on the estimated RLS output signal and tap weights. Computer simulation results verify these two modes of operation of the RLMS beamforming algorithm. Furthermore, the convergence performance of RLMS is shown to be quite insensitive to variations in SNR of the input signal as well as step sizes associated with the RLS and LMS sections. Keywords-Fixed beam, RLMS algorithm, adaptive antenna array beam forming.

Analysis of the RLMS adaptive beamforming algorithm implemented with finite precision

“…The performance of the RLMS beamforming algorithm has previously been presented in [4,[10][11][12]. These earlier results are based on the RLMS algorithm being implemented with full precision for operation under various channel conditions, including additive white Gaussian noise, and cochannel interference.…”

“…Furthermore, RLMS can operate with a noisy reference signal. As described in, [11,12] RLMS can be used to achieve an accurate fixed beam by prior setting the elements of F with prescribed values for the required direction. On the other hand, the beam direction can also be made adaptive to automatically track the target signal.…”

“…In this paper, we extend our study on the RLMS algorithm [4,[10][11][12] by analyzing the effect on the convergence behavior due to the use of finite precision arithmetic for its implementation. Some approximations are introduced in order to simplify the analysis.…”

An improved exclusive region scheduling algorithm‐based timeslot allocation scheme for mmWave WPANs

“…As it is desired to utilize smart antennas array in 60-GHz band, both omnidirectional and directional antennas will be considered for analysis. Currently, there are many researches on beamforming techniquesbased spatial reuse schemes [2][3][4]. It is shown that the multibeam smart antennas are more suitable for 60-GHz WPANs based on the considerations of low cost and low complexity.…”

An improved ER scheduling algorithm based spatial reuse scheme for mmWave WPANs

“…Currently, there are many researches on spatial reuse schemes based on beamforming techniques [2,3]. Although the short wavelength of the 60GHz band makes it possible to realize small size of antenna array at terminal devices, it appears some other problems.…”