Resource allocation considerations for multi-carrier LTE-Advanced systems operating in backward compatible mode

In this paper we focus on LTE-Advanced with backward compatibility, which serves a mixture of LTE-Advanced and LTE-Rel´8 users. Aggregation of multiple component carriers (CCs) to form a wide spectrum is assumed in order to fulfill the bandwidth requirement for the next generation systems, thereby leading to a multi-carrier system. Although a LTE-Advanced user can simultaneously access all the CCs, a LTE-Rel´8 user is restricted to operate on a single CC at a time. Different methods for balancing the load across these CCs will affect the system performance. This is investigated through both analytical methods and system level simulations. Bearing in mind that the LTE-Advanced users are scheduled on more CCs than the LTE-Rel´8 users, we propose a simple cross CC packet scheduling algorithm that improves the resource allocation fairness among the two categories of users. This simple scheduling algorithm is shown to be effective in providing better coverage performance with no loss of the overall cell throughput, as compared to independent scheduling per CC.