In a radio network with single source-destination pair and some relays, a link between any two nodes is considered to have same or zero path loss. However in practice some links may have considerably high path loss than others but still being useful. In this report, we take into account signals received from these links also. indent Our system model consists of a source-destination pair with two layers of relays in which weaker links between source and second layer and between the first layer and destination are also considered. We propose some protocols in this system model, run simulations under optimum power allocation, and compare these protocols. We show that under reasonable channel strength of these weaker links, the proposed protocols perform ($ approx 2$ dB) better than the existing basic protocol. As expected, the degree of improvement increases with the strength of the weaker links. We also show that with the receive channel knowledge in relays, the reliability and data rate are improved.
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