Joint optimization with power and rate control in HARQ system
Zhaoyang Zhang · Journal of Zhejiang University(Engineering Science) · 2009
The relation among maximum retransmission times,power in every transmission,sub-packet length,modulation bits,coding rate in hybrid automatic repeat request(HARQ) transmission mode and the system throughput was studied.A feed-back mode with channel parameters was proposed based on IEEE 802.16e protocol to enhance the throughput of wireless transmission system.The constraint of power allocation and packet error rate in the mode was given,which is different from that in transmission mode with fixed parameters.A model under additive white Gaussian noise channel was established to analyze the influence on the throughput caused by different parameters and the corresponding optimization dependent on certain parameter.A sub-optimal algorithm was proposed to adaptively update parameters.Simulation results show that the algorithm can achieve much higher system performance than the traditional algorithm with constant parameters.The system throughput dynamically increases when channel condition gets better.The algorithm can get high system throughput with low complexity when channel condition can be precisely detected by the receiver.