Smart Downlink Scheduling for Multimedia Streaming over LTE Networks with Hard Hand-Off

This paper presents a novel smart down-link scheduling scheme to enhance the performance of multimedia transmission over LTE (Long Term Evolution) networks. LTE represents a promising framework for next generation broadband multimedia services because of its significantly increased data rate over 3G cellular networks. However, the current LTE scheduling scheme has been designed largely for general data traffic without adequate consideration of multimedia characteristics. Moreover, the “hard” hand-off (HO) procedure adopted in LTE will further degrade the multimedia services when the mobile user moves from one cell to another. Even with increased data rate, current LTE systems still cannot meet the expected quality-of-service (QoS) to the mobile users under various mobility scenarios, especially when the hard HO is evoked. Aiming at overcoming these major challenges, we develop in this research a QoS-driven smart down-link scheduling scheme for enhanced multimedia transmission over LTE network.

The proposed design shall consider the following QoS metrics: 1) The delay constraint of voice-over-IP (VoIP) flow; 2) The packet deadline of video flow; 3) The service degradation induced by hard HO procedure. We achieve the design objectives by creating three QoS driven operational control modules: a transmission delay control module to ensure the on-time arrival of various types of multimedia data, a HO control module to warrant continuous multimedia services when the user moves across a cell boundary, and a resource allocation module to strategically map the requested flows to best-fit radio resource blocks. Simulation results confirm the performance gain of the proposed scheme.