System architecture and cross-layer optimization of video broadcast over WiMAX

Video broadcast and mobile TV have received significant interests from both academia and industry recently. The emerging mobile WiMAX (802.16e) is capable of providing high data rate and flexible quality of service (QoS) mechanisms, making the support of mobile TV very attractive. However, how to efficiently deliver video broadcast over WiMAX is not straightforward, especially in the multi-BS mode. The multi-BS mode requires multiple BSs to be synchronized in the transmission of common multicast/broadcast data. In this paper, we first identify the key design issues for video broadcast over WiMAX in the multi-BS mode. Then, we present an end-to-end solution which fully addresses key issues such as synchronization, energy efficiency and robust video quality. Moreover, we propose a methodology to optimize the coverage, the spectrum efficiency and the video quality. Results show that our proposed scheme can significantly improve the coverage and spectrum efficiency while satisfying video quality requirements.

I. Introduction

Mobile WiMAX has made major strides over the past year and is rapidly proving itself as a leading solution for broadband wireless services. The Mobile WiMAX Air Interface is based on the IEEE 802.16-2004 [1] Air Interface Standard and the IEEE 802.16e Mobile Amendment [2]. Mobile WiMAX Air Interface adopts the Orthogonal Frequency Division Multiple Access (OFDMA) for improved multi-path performance in the non-line-of-sight (NLoS) environments. The inclusion of SIMO/MIMO antenna techniques along with flexible OFDMA sub-channelization schemes, advanced coding and modulation all enable the Mobile WiMAX technology to support high data rates. In addition, OFDMA subchannelization and MAP (a header part of OFDMA frame used to indicate the control information of current frame, like the allocation of subchannel and slot) based signaling schemes provide a flexible mechanism for optimal scheduling of space, frequency and time resources over the air interface on a frame-by-frame basis.