Analysis and performance evaluation of scalable video coding over heterogeneous cellular networks

Deployment of small cells along with macro base stations is considered as one of the most promising solutions for increasing the capacity and coverage of the wireless networks. Wireless networks comprising of various levels of base stations are called heterogeneous cellular networks (HCN). In this paper, the structure of HCNs is utilized for transmission of scalable video coding (SVC). In such networks, higher density of the stations increases the probability of handover for mobile users. Packet loss, delay, and failure in handover degrade the quality of media streaming services. In the proposed scheme, for two-layer spatially scalable coded video, due to the umbrella coverage of a macrocell, macro base station (MBS) is suitable for transmission of the base layer content to the users within its coverage area to minimize the costs of handover. Moreover, the enhancement layer is transmitted by an access point (AP) offering maximum biased received power. To evaluate the performance of the proposed scheme, first, the data rate distributions for a stationary user are modeled. Then, using the tools from stochastic geometry, theoretical expressions are derived for both horizontal and vertical handover probabilities experienced by a mobile user. In addition, two performance metrics are quantified to analyze the performance of the proposed scheme. These are the standard-definition (SD) outage probability and the high-definition probability. In this paper we show that using SVC over HCNs the SD outage probability is reduced by 50% to 55% compared to the conventional methods, where all layers receive from one AP.