In two-way relay network (TWRN), end nodes may
have different quality-of-service (QoS) requirements according
to their priority, traffic demand, and/or their downlink and
uplink split ratio. In this paper, the heterogeneity among network
users that have different traffic load/demands is considered by
assuming a weighted fairness between the two end nodes. An
energy efficient design is proposed for two-way relaying (TWR)
with time division broadcast (TDBC) protocol that minimizes
the allocated power to the two transceivers and the relay node
under a weighted quality-of-service (QoS) bidirectional data rates
requirement with weighting factor (α). This design utilizes the
signal combining process at the relay node in TDBC, also known
as relay power allocation (RPA), to provide a new simpler way
to ensure the weighted rates without increasing the complexity
to control different power allocation of the three nodes. Adaptive
calculation of the relay power allocation factor, epsilon, is adopted for combining the two received signals to satisfy the QoS requirements. Simulation results show an improvement in the efficiency in terms of the average allocated power and a perfect users fairness compared with scenarios where a predetermined fixed value of epsilon is used. |
