An adaptive receiver of joint data and channel estimation for meteor burst communications

SUMMARYThe swift growth of the mobile users and limited availability of bandwidth lead to the requirement of effective channel allocation process. Channel allocation becomes tedious in vehicular ad hoc network, as the mobility of the nodes is high. So, in this paper, we propose a method called as cross layer based channel reservation with preemption (CCRP) method that performs channel allocation process by estimating the handoffs in vehicular ad hoc networks. The time estimated is communicated from physical layer to medium access control layer using a cross-layer design. The reusability concept is used, and the channels are divided into three groups. The different cells acquire different groups based on the database status and exclusively to avoid interference. Preemption is incorporated to give the highest priority to real time originating calls and real time handoff calls. The performance of the proposed method, CCRP, is compared with the legacy systems such as cooperative reservation of service channels and very fast handover scheme in terms of dropping probability, blocking probability, and handoff latency. The results show that the proposed algorithm, CCRP, performs better in comparison.

Section: Related Workmentioning

confidence: 99%

An efficient cross layer based channel reservation method for vehicular networks

Saritha

Viswanatham

2013

“…Adaptive system identification (ASI) includes many applications such as interference cancelation [1][2][3], spectral subtraction [4,5], wireless localization [6][7][8][9], channel equalization [10][11][12][13], and adaptive beamforming [14]. One of most popular algorithms is least mean square (LMS), which is proposed by Widrow et al [15].…”

Section: Introductionmentioning

confidence: 99%

Adaptive system identification using robust LMS/F algorithm

Gui

Peng

Adachi

2013

Adaptive system identification (ASI) problems have attracted both academic and industrial attentions for a long time. As one of the classical approaches for ASI, performance of least mean square (LMS) is unstable in low signal-to-noise ratio (SNR) region. On the contrary, least mean fourth (LMF) algorithm is difficult to implement in practical system because of its high computational complexity in high SNR region, and hence it is usually neglected by researchers. In this paper, we propose an effective approach to identify unknown system adaptively by using combined LMS and LMF algorithms in different SNR regions. Experiment-based parameter selection is established to optimize the performance as well as to keep the low computational complexity.

“…We only assume that the path delay is known. Several methods for estimating the path delay is presented in [26][27][28][29][30]. In a DS-CDMA system, because of the orthogonality between the spreading codes, the desired signal power is much larger than each interference signal power after despreading.…”

Section: Introductionmentioning

confidence: 99%

Three novel simple beamforming algorithms for CDMA communication systems

Tavassoli

Abolhassani

Oraizi

et al. 2012

SUMMARYTo apply a beamforming algorithm with a linear array of N antennas in real wireless communication systems, two main issues should be addressed: Algorithm complexity and number of antennas. In this paper, we propose three simple beamforming algorithms for direct sequence code division multiple access systems. We first propose a new framework to obtain the updating equation for the weight vector using PCA. Then, using this framework, four different objective functions are used as examples to illustrate how to obtain new adaptive algorithms. We demonstrate that these objective functions lead to three novel blind algorithms, with two of them resulting in the same algorithm. Moreover, they have considerably low complexities, requiring only 2N–1 complex additions and either 2N+1 or 2N complex multiplications for a single run. We evaluate the performances of these algorithms in estimating the angle‐of‐arrival of the desired signal and in producing the array beam pattern, and in alleviating the BER in Rayleigh fading and AWGN channels. In summary, these new beamforming algorithms obtained based on the proposed framework operate as blind algorithms, have low computational complexities, and offer desirable performances even if N is restricted.Copyright © 2012 John Wiley & Sons, Ltd.