Achievable rate and error performance of an amplify and forward multi-way relay network in the presence of imperfect channel estimation

2016 ◽  
Vol 10 (3) ◽  
pp. 272-282 ◽  
Author(s):  
Shama Naz Islam
Keyword(s):  
Channel Estimation ◽  
Relay Network ◽  
Achievable Rate ◽  
Amplify And Forward ◽  
Error Performance ◽  
Imperfect Channel Estimation

scholarly journals Superimposed Training-Based Channel Estimation for MIMO Relay Networks

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Xiaoyan Xu ◽  
Jianjun Wu ◽  
Shubo Ren ◽  
Lingyang Song ◽  
Haige Xiang
Keyword(s):  
Channel Estimation ◽  
Multiple Input Multiple Output ◽  
Estimation Algorithm ◽  
Relay Network ◽  
Mimo Channel ◽  
Amplify And Forward ◽  
Error Performance ◽  
Superimposed Training ◽  
Training Strategy ◽  
The Individual

We introduce the superimposed training strategy into the multiple-input multiple-output (MIMO) amplify-and-forward (AF) one-way relay network (OWRN) to perform the individual channel estimation at the destination. Through the superposition of a group of additional training vectors at the relay subject to power allocation, the separated estimates of the source-relay and relay-destination channels can be obtained directly at the destination, and the accordance with the two-hop AF strategy can be guaranteed at the same time. The closed-form Bayesian Cramér-Rao lower bound (CRLB) is derived for the estimation of two sets of flat-fading MIMO channel under random channel parameters and further exploited to design the optimal training vectors. A specific suboptimal channel estimation algorithm is applied in the MIMO AF OWRN using the optimal training sequences, and the normalized mean square error performance for the estimation is provided to verify the Bayesian CRLB results.

scholarly journals Individual Channel Estimation in a Diamond Relay Network Using Relay-Assisted Training

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Xianwen He ◽  
Gaoqi Dou ◽  
Jun Gao
Keyword(s):  
Channel Estimation ◽  
Relay Node ◽  
Spatial Diversity ◽  
Relay Network ◽  
Destination Node ◽  
Training Design ◽  
Amplify And Forward ◽  
Relay Nodes ◽  
Training Scheme ◽  
Data Signal

We consider the training design and channel estimation in the amplify-and-forward (AF) diamond relay network. Our strategy is to transmit the source training in time-multiplexing (TM) mode while each relay node superimposes its own relay training over the amplified received data signal without bandwidth expansion. The principal challenge is to obtain accurate channel state information (CSI) of second-hop link due to the multiaccess interference (MAI) and cooperative data interference (CDI). To maintain the orthogonality between data and training, a modified relay-assisted training scheme is proposed to migrate the CDI, where some of the cooperative data at the relay are discarded to accommodate relay training. Meanwhile, a couple of optimal zero-correlation zone (ZCZ) relay-assisted sequences are designed to avoid MAI. At the destination node, the received signals from the two relay nodes are combined to achieve spatial diversity and enhanced data reliability. The simulation results are presented to validate the performance of the proposed schemes.

scholarly journals The Optimal Power Allocation with Hybrid Relaying Based on Channel Condition

2018 ◽  
Author(s):  
Junpyo Jeon ◽  
Yeonggyu Shim ◽  
Hyuncheol Park
Keyword(s):  
Power Allocation ◽  
Relay Network ◽  
Achievable Rate ◽  
Optimal Power Allocation ◽  
Allocation Scheme ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Transmit Power ◽  
Optimal Power ◽  
Af Relay

This paper considers a hybrid relay network consisting of the source, the amplify-and-forward (AF) relay, the decode-and-forward (DF) relay, and the destination. We propose the optimal power allocation schemes between two different relays which maximize the achievable rate under a sum relay power constraint for given channel gains and transmit power from source. By solving the optimization problem to maximize the achievable rate for each relay network, the transmit power values in closed-form are derived. When the channel gains are the same, the optimal power allocation scheme for AF-DF relay network proves that a more power should be allocated at the first relay to maximize the achievable rate. In case of the DF-AF relay network, we derive the optimal power allocation scheme for the possible four cases. Under the same SNR condition at the first hop, we show that the achievable rate of AF-DF relay network is greater than that of DF-AF relay network when the channel gain between two relays is higher than that between the second relay and destination. Simulation results show that the proposed power allocation schemes provide a higher achievable rate than the equal power allocation schemes.

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