Dynamic resource allocation algorithms for long term evolution (LTE) wireless broadband networks

Abstract

Following the successful standardization of High-Speed Packet Access (HSPA), the 3rd Generation Partnership Project (3GPP) recently specified the Long Term Evolution (LTE) as a next generation radio network technology to meet the increasing performance requirements of mobile broadband. The results include a flexible and spectrally efficient radio link protocol design with low overhead. The first release of LTE provides peak rates of 300 Mbps in downlink and 75 Mbps in uplink. It is a significant increase in spectrum efficiency compared to the previous cellular systems. Single-Carrier Frequency Division Multiple Access (SC-FDMA) has been selected as the uplink access scheme in the LTE. With SC-FDMA, the frequency spectrum resource is divided into time-frequency grids, referred to as resource blocks (RBs). Multiple-access is achieved by distributing resource blocks to users. The function of resource block allocation algorithms is to distribute resource blocks among users in a fair and efficient manner. The Modulation and coding scheme is determined adaptively according to the time-varying channel conditions. Sounding Reference Signals (SRS) are transmitted in the uplink direction to allow for the base station to estimate the uplink channel quality at different frequencies. The LTE system supports wideband SRS and narrowband SRS. We have developed an in-house simulation program in C++ to evaluate and compare the performance of CASA and ICAS algorithms in terms of packet loss ratio, delay, and throughput. Simulation results show that the proposed algorithms are able to satisfy the QoS requirements. Both of proposed algorithms support multiple CoSs simultaneously without impeding the first class (Expedited Forwarding) transmission. Also, both of the proposed algorithms achieve high throughput in a large range cell.