The 3rd Generation Partnership Project (3GPP) specifies a hybrid cellular system that includes long-term evolution (LTE) cooperated with the existing universal mobile telecommunications system (UMTS). In the hybrid cellular system, the base station and user equipment (UE) use various modulation modes to support different generation cellular communications. In this case, each radio interface should be loaded in balance to achieve efficient radio resource utilization.

This paper is motivated by the idea that the load balance between different radio interfaces can be achieved with consideration of the packet loss rate, which is caused by the interference according to the mobile node’s location and high mobility speed. The paper proposes an efficient adaptive radio resource allocation algorithm that consists of four phases. In the first phases, the load on each interface is determined by computing the allocated bandwidth and subframes. In the second phase, the radio interface is selected based on the load of each interface, the mobile node’s velocity, and the reward of the required traffic. In the third and fourth phases, an optimal code set and maximum allowed number of resource blocks are determined for efficient resource allocation for UMTS and LTE, respectively. Simulation shows the proposed algorithm outperforms existing technologies in terms of fairness, system utilization, and other metrics, with various modulations, number of codes, and traffic arrival rates.

Since the mobile node’s mobility is the main consideration of the proposed algorithm, it would be more interesting if the simulation scenario included mobility. The intended audience is the researchers and engineers in the wireless communications area. The paper gives a novel idea for selecting an appropriate module based on reward for a base station supporting multiple interfaces.