Resource allocation for goodput optimization in parallel subchannels with error correction and selective repeat ARQ

This paper deals with the problem of allocating bits and power among a set of parallel frequency-flat subchannels. The objective is to maximize the number of information bits delivered without error to the user by unit of time, or good-put. We consider a frame-oriented transmission with convolutional coding, hard Viterbi decoding, and selective repeat automatic repeat request (ARQ) retransmission protocol. An expression for the goodput of the considered communication system is derived. Different bit and power allocations strategies are proposed and compared to one another using simulations. It turns out that the best trade-off between performance and complexity is achieved by allocating the power in such a way that the bit error rate is equal on all subchannels, and by allocating the bits by rounding the solution to the problem obtained by relaxing the constraint of integer constellation sizes.