Dual-Hop Amplify-and-Forward Relay Systems with EGC over M2M Fading Channels Under LOS Conditions: Channel Statistics and System Performance Analysis

Abstract

Dual-Hop Amplify-and-Forward Relay Systems with EGC over M2M Fading Channels Under LOS Conditions http://dx.doi. org/10.5772/55333 201 in parallel between the source mobile station and the destination mobile station, as illustrated in Fig. 1. It can be seen in this figure that the direct transmission link from the source mobile station to the destination mobile station is also unobstructed. It is assumed that all mobile stations in the network, i.e., the source mobile station, the destination mobile station, and the K mobile relays do not transmit and receive a signal at the same time in the same frequency band. This can be achieved by using the time-division multiple-access (TDMA) based amplify-and-forward relay protocols proposed in [41,42]. Thus, the signals from the K + 1 diversity branches in different time slots can be combined at the destination mobile station using EGC.Let us denote the signal transmitted by the source mobile station as s(t). Then, the signal r (0) (t) received at the destination mobile station from the direct transmission link between the source mobile station and the destination mobile station can be written asρ (t)s(t) + n (0) (t)where µρ (t) models the complex channel gain of the fading channel from the source mobile station to the destination mobile station under LOS propagation conditions. The non-zero-mean complex Gaussian process µ source mobile station to the destination mobile station, i.e., µ (0) ρ (t) = µ (0) (t) + m (0) (t). In addition, n (0) (t) denotes a zero-mean additive white Gaussian noise (AWGN) process with variance N 0 /2, where N 0 is the noise power spectral density.Similarly, we can express the signal r (k) (t) received from the kth diversity branch at the destination mobile station aswhere ς (k) ρ (t) (k = 1, 2, . . . , K) represents the complex channel gain of the kth subchannel from the source mobile station to the destination mobile station via the kth mobile relay under LOS propagation conditions. Furthermore, n (k) T (t) ∀ k = 1, 2, . . . , K is the total noise in the link from the source mobile station to the destination mobile station via the kth mobile relay. This noise term is analyzed below.Each fading process ς (2) is modeled as a weighted non-zero-mean complex double Gaussian process of the formfor k = 1, 2, . . . , K. In (3), each µ (i) ρ (t) is a non-zero-mean complex Gaussian process. For all odd superscripts i, i.e., i = 2k − 1 = 1, 3, . . . , (2K − 1), the Gaussian process µ (i) ρ (t) describes the sum of the scattered component µ (i) (t) and the LOS component m (i) (t) of the ith subchannel between the source mobile station and the kth mobile relay, i.e., µ (i) ρ (t) = µ (i) (t) + m (i) (t). Whereas, for all even superscripts i, i.e., i = 2k = 2, 4, . . . , 2K, the Gaussian process µ (i) ρ (t) denotes the sum of the scattered component µ (i) (t) and the LOS component m (i) (t) of the ith subchannel between the kth mobile relay and the destination mobile station. Each scattered component µ (i) (t) (i = 0, 1, 2, . . . , 2K)...

On Selection Combining Diversity in Dual-Hop Relaying Systems Over Double Rice Channels: Fade Statistics and Performance Analysis

“…respectively. In addition, for DPSK modulation (M = 2), the results obtained from ( 48), (49), and (50), are, as expected, in agreement with [32, eq. ( 19)], [32, eq.…”

“…Under such condition, the SEP to be presented can be seen as a lower bound of that corresponding to the case where the noise of the relays cannot be ignored. Besides, the subsequent performance analysis applies also if the overall additive noise, corresponding to the relaying path, is Gaussian [49].…”