M. K. Arti

Performance Analysis of AF Based Hybrid Satellite-Terrestrial Cooperative Network over Generalized Fading Channels

In this paper, the transmission of signals in a hybrid satellite-terrestrial link is considered. In particular, we address the problem of amplify-and-forward (AF) relaying in a hybrid satellite-terrestrial link, where a masked destination node receives the relayed transmission from a terrestrial link and direct transmission from the satellite link. The satellite-relay and satellite-destination links are assumed to follow the Shadowed-Rician fading; and the channel of the terrestrial link between the relay and destination is assumed to follow the Nakagami-m fading. The average symbol error rate of the considered AF cooperative scheme for M-ary phase shift keying constellation is derived for these generalized fading channels. Moreover, analytical diversity order of the hybrid system is also obtained.

Beamforming and Combining in Hybrid Satellite-Terrestrial Cooperative Systems

In this paper, we consider the transmission of signals in a hybrid satellite-terrestrial cooperative system. In particular, we address the problem of beamforming and combining based amplify-and-forward (AF) relaying in a hybrid satellite-terrestrial cooperative system. In this set-up, a multiple antenna based relay node forwards the received satellite signals to the destination, by using a beamforming vector, and multiple antenna based destination node uses maximal ratio combining. The approximate average symbol error rate of the considered beamforming and combining based hybrid AF cooperative scheme for M-ary phase shift keying constellation is derived; analytical diversity order of the hybrid system is also obtained. Moreover, diversity calculations for some specific antenna configurations are shown for providing useful insight of the proposed scheme, at high signal-to-noise ratio.

On the Closed-Form Performance Analysis of Maximal Ratio Combining in Shadowed-Rician Fading LMS Channels

In this paper, the maximal ratio combining (MRC) scheme in Shadowed-Rician (SR) fading land mobile satellite (LMS) channels is studied. The MRC scheme for SR fading LMS channels has been studied in existing literature; however, most of the existing analytical results are in the form of infinite power series, which are not in closed-form. In this paper, we derive approximate closed-form expressions of the probability density function and cumulative distribution function of the received signal-to-noise ratio of the MRC based receiver in SR fading LMS channels. Then we provide approximate closed-form expressions of the bit error rate (BER), outage probability, and capacity of the considered scheme. One of the derived closed-form BER expressions is found useful for obtaining the analytical diversity order and coding gain of the considered MRC scheme.

Selection Beamforming and Combining in Decode-and-Forward MIMO Relay Networks

In this paper, decode-and-forward (DF) based cooperation in a multiple antenna based wireless communication system is studied. In particular, we address the problem of beamforming and combining in a DF multiple-input multiple-output (MIMO) relay network with transmission path selection. A maximum eigenvalue based criterion is used for selection of best transmission path between source and destination nodes. We derive the average bit error rate of the considered cooperative scheme for binary phase shift keying constellation over Rayleigh fading channels. In addition, analytical diversity order of the beamforming and combining based DF MIMO relay system is obtained, for some special cases.

Performance Analysis of Hybrid Satellite-Terrestrial FSO Cooperative System

In this letter, the transmission of signals in a hybrid satellite-terrestrial free space optical (FSO) cooperative link is considered. In particular, we address the problem of amplify-and-forward (AF) relaying in a hybrid satellite-terrestrial FSO cooperative link, where a masked destination node receives the relayed transmission from an FSO link. The satellite-relay link is assumed to follow the shadowed-Rician fading, and the irradiance of the FSO link between the relay and destination is assumed to follow the gamma-gamma distribution. The approximate average symbol error rate of the considered AF cooperative scheme for M-ary phase shift keying constellation is derived; analytical diversity order of the hybrid cooperative system is also obtained.

Beamforming and Combining in Two-Way AF MIMO Relay Networks

In this letter, we propose a beamforming and combining scheme for a two-way amplify-and-forward (AF) multiple-input multiple-output (MIMO) relay network. An approximate expression for the symbol error rate of the scheme in Rayleigh fading for M-ary phase-shift keying is obtained based on the moment generating function of the instantaneous received signal-to-noise ratio. The diversity order is also analytically derived. It is shown by simulations that the proposed scheme outperforms existing schemes for beamforming and combining in two-way AF MIMO relay systems. We also discuss beamforming and combining in a two-way AF MIMO relay system with estimated channel gains.

Performance Analysis of Hop-by-Hop Beamforming and Combining in DF MIMO Relay System over Nakagami-m Fading Channels

In this paper, we study hop-by-hop beamforming and combining in a decode-and-forward (DF) multiple-input multiple-output (MIMO) relay network, with two antennas at each node, over Nakagami-m fading channels. We derive a closed-form expression of the approximate average bit error rate of the considered cooperative scheme with M-ary phase shift keying constellation. In addition, analytical outage probability and diversity order of the considered DF MIMO relay system are also obtained.

Performance Analysis of Two-Way AF MIMO Relaying of OSTBCs With Imperfect Channel Gains

In this paper, we consider the relaying of orthogonal space-time block codes (OSTBCs) in a two-way amplify-and-forward (AF) multiple-input-multiple-output (MIMO) relay system with estimated channel state information (CSI). A simple four-phase protocol is used for training and OSTBC data transmission. Decoding of OSTBC data at a user terminal is performed by replacing the exact CSI by the estimated CSI in a maximum-likelihood (ML) decoder. Tight approximations for the moment-generating function (MGF) of the received signal-to-noise ratio (SNR) at a user is derived under Rayleigh fading by ignoring the higher order noise terms. Analytical average error performance of the considered cooperative scheme is derived by using the MGF expression. Moreover, the analytical diversity order of the considered scheme is also obtained for certain system configurations. It is shown by simulations and analysis that the channel estimation does not affect the diversity order of the OSTBC-based two-way AF MIMO relay system.

Multi-User Relaying of High-Rate Space---Time Code in Cooperative Networks

In this paper, we propose high-rate space–time coding for cooperative wireless networks to reduce the overall delay incurred in relaying signals to multiple receivers. The relay structure is optimized in order to achieve maximum SNR at the receiver nodes. The proposed scheme provides a significant reduction in the delay required for the relaying and transmission of the signals to the multiple receivers with a minute loss in performance. We have also shown by simulation that this loss in the performance could be recovered by selecting more number of relays. We propose two relaying strategies for high-rate space–time codes, which are very useful in providing high data-rate in wireless cooperative networks.

Relay Strategies for High Rate Space-Time Code in Cooperative MIMO Networks

In this paper, we combine the idea of high rate space-time codes with the cooperative MIMO wireless networks to reduce the overall delay incurred in relaying signals to more than one receiver. The relay structure is optimized in order to achieve maximum SNR at the receiver nodes. This combination provides a significant reduction in the delay required for the relaying and transmission of the signals to the multiple receivers with a minute loss in performance. We have also shown that this loss in the performance could be recovered by selecting more number of relays. We propose three different relaying strategies for high rate space-time codes, which are very useful in providing faster handoffs for wireless networks.