Abstract:

This paper studies a resource allocation problem for heterogeneous services in amplify-and-forward
OFDM relay system under separate power constraints. A resource allocation scheme is proposed to maximize
the data rate of non-realtime service (NRTS) users while satisfying the requirement of realtime service (RTS)
users. The problem is decomposed into two sub-problems: resource allocation for RTS and NRTS. The problem
of RTS is solved with the Lagrangian method, while for NRTS, each subcarrier is allocated to the user with the
best channel gain, and a two-step method is proposed for power allocation. First, the initial power allocation
is done under the total power constraint. The subcarrier power is adjusted to satisfy the separate power
constraints. A low complexity algorithm is proposed for subcarrier set allocation. Simulation results show that
the proposed scheme optimizes the system performance with low complexity while satisfying the requirements
of heterogeneous services users.

Key words: OFDMA, relay system, resource allocation, amplify-and-forward, heterogeneous services