Orthogonal Frequency Division Multiple Access in WiMAX and LTE: A Comparison

Orthogonal frequency-division multiple access has been adopted by both the WiMAX and Long Term Evolution standards, which are the two main contenders in the 4G wireless scenario. In this article, we do a detailed comparison of the implementation of OFDMA in LTE and WiMAX. The multiuser diversity advantage of OFDMA is well used in LTE, whereas the frequency diversity advantage is nicely exploited in WiMAX. The physical layer overhead in LTE is significantly better than in WiMAX. The network entry process of an LTE mobile is simpler than in a WiMAX mobile. In addition, LTE systems are expected to react faster to changes in the traffic and channel conditions due to the smaller frame times. However, the OFDMA design in WiMAX will cater for more extreme channel conditions, which is perhaps more than what is expected in practice as our investigation reveals.