Jianxiong Huang

ABEP of amplify-and-forward cooperation in Nakagami-m fading channels with arbitrary m

An asymptotic average bit error probability (ABEP) analysis is presented for amplify-and-forward (AF) cooperation with multi-branch dual-hop relays in independent Nakagami-m fading channels. The approximate probability density function (PDF) of the instantaneous dual-hop link power at high SNR region is derived, and indicates that the relay link is dominated by the more severely faded hop. Simple and general asymptotic ABEP expressions are presented for all-participate AF (AP-AF) and selective AF (S-AF) cooperation employing general Gray bitmapped constellation. The results are quite simple and general for arbitrary value of severity parameter m ges 0.5. It is shown that S-AF does not necessarily outperform AP-AF in terms of coding gain under conventional equal power allocation as in the Rayleigh fading environment. Whether or not S-AF outperforms AP-AF depends only upon the fading severity parameters and is irrelevant to the channel gains. Simulation results verify the tightness of the presented analysis at high SNR region.

Opportunistic cooperation and optimal power allocation for wireless sensor networks

Cooperative communications is a promising technology to improve the performance of wireless sensor networks. In this paper, a dual-hop wireless cooperative network with opportunistic amplify-and-forward relaying is investigated over independent and non-identically distributed Nakagami-m fading channels. Due to the complicated form of the probability density function of the instantaneous signal-to-noise ratio (SNR), the symbol error rate and outage probability expressions are difficult to obtain in closed form. Taking advantage of Maclaurin series expansion of the probability density function of the output instantaneous SNR, we present the asymptotic symbol error rate and outage probability expressions at medium and high SNR regions, and the optimal power allocation scheme between the source and opportunistic relay is also proposed to minimize the outage probability. Simulation results demonstrate that the derived symbol error rate and outage probability matches well with the Monte-Carlo simulations. In addition, it is verified that the optimal power allocation scheme outperforms the equal power allocation scheme in terms of outage probability.

Symbol error rate of selective cooperation in Nakagami-m environments

In this paper, we present asymptotic symbol error rate (SER) analysis for selective amplify-and-forward (AF) cooperative systems with arbitrary number of relays. Any relay channel involved experiences independent and non-identically distributed Nakagami-m fading. Due to the complicated form of the probability density function (PDF) of the instantaneous dual-hop link signal-to-noise ratio (SNR), we provide its tight approximation at high SNR regions. The result reveals that the dual-hop relay link is dominated by the more severely fading hop and is extendable to multiple-relay scenarios. Further, SER is obtained for selective relaying systems, which is in quite simple and generalized form. Its indicated that although selection among relays achieves the same diversity gain as the conventional all-participate schemes, it results in significant coding gain improvements. Simulation results verify the tightness of presented analysis at medium to high SNR regions in Nakagami-m environments with arbitrary severity parameter m ≥ 0.5.

Performance analysis of opportunistic cooperative communication over Nakagami-m fading channels

In this paper, a dual-hop wireless cooperative network with opportunistic amplify-and-forward (AF) relaying is investigated over independent and non-identically distributed Nakagami-m fading channels. Due to the complicated form of the probability density function of the instantaneous dual-hop link signal-to-noise ratio (SNR), the symbol error rate and outage probability expressions are difficult to obtain in closed form. Taking advantage of Maclaurin series expansion to simplify the probability density function of the output SNR, we present the tight approximate symbol error rate and outage probability expressions at medium and high SNR regions for opportunistic AF cooperative network. Computer simulation results reveal that the analysis expressions about symbol error rate and outage probability are accurate at medium and high SNR regions.

On the performance of partial relay selection in dual-hop relaying with beamforming

A scheme combining partial relay selection and beamforming in the dual-hop relaying system is proposed. We present the performance analysis of the scheme in Nakagami-m fading by providing closed-form expressions for the outage probability and average bit error probability as well as simple approximations for the two metrics to quantify the performance in high signal-to-noise ratio regime. In the numerical results, the correctness of the theoretical results is validated and the superior performance of the proposed scheme is also shown.