Resource allocation in OFDMA-based distributed antenna systems

This paper proposes and investigates an optimal resource allocation scheme in the downlink multiuser distributed antenna system (DAS), which is one of the promising systems to provide high data rate in wireless communications. Compared with the conventional cellular system, the resource allocation in the multiuser DAS must consider the conditions of multiple channels between multiple remote antenna unites (RAUs) and any user, which increases the complexity of the resource allocation. Orthogonal frequency division multiple access (OFDMA) is also considered for the resource allocation in the downlink DAS. Therefore, subcarrier allocation, power allocation and bit allocation are studied in the OFDMA-based DAS. To reduce the complexity of the resource allocation in the downlink OFDMA-based DAS, the chunk allocation technique is also adopted by grouping a set of neighboring subcarriers into one chunk and allocating resources to users chunk by chunk. In order to provide insights in the OFDMA-based DAS, the effect of the number of RAUs used to communicate with each user is investigated. The numerical results show that based on the proposed resource allocation scheme, the location of the user can impact the number of RAUs that a user needs to connect.