Superposition Coded Multicast for Wireless Data

Description

UW researchers have developed a method for achieving efficient and reliable data communication which can be applied to wireless communications across a diversity of different receiver channel quality states which significantly improves the quality of the end-users experience while optimizing the use of the service provider’s bandwidth in multicast applications.

Background

Wireless-channel fading and the loss of the integrity of transmitted data is a major problem for all wireless communication systems especially when it comes to broadcasting bandwidth-demanding video content associated with the emergence of Internet Protocol TV (IPTV) services. Channel fading can occur for a variety of reasons (eg. distance of user from base station, moving vehicle transmission, city buildings, etc.) which makes efficient multicasting a major challenge for wireless service providers.

In wireless video multicast, it is necessary to pick a certain transmission rate that majority of receivers in each coverage area could be able to receive the data with minimal loss. This will lead to underutilizing the capacity of the end-users with good wireless channel condition. At the same time, end-users with low wireless channel quality might still suffer of poor signal reception. In general, the transmission speed (modulation scheme) would be selected very conservatively to assure the reception of the signal by the majority of subscribers. This conservative transmission rate selection is the main cause of insufficient use of frequency spectrum and would waste a lot of service providers’ infrastructure capacity.

To address this channel quality problem, coding/decoding techniques for optimizing bandwidth utilization have been used; however the overall performance is still heavily dependent on the quality of the receiver’s wireless channel. UW researchers have developed a novel methodology that generates a proprietary coded intelligent multicast signal that combines Scalable Video Coding (SVC), Multiple Description Coding (MDC) and Superposition Coding (SPC) together to maximize the received video quality for all intended receivers, regardless of receiver channel quality status.

Advantages/Uses

1.        Efficient wireless video multicast in entertainment and advertising industry (optimal use of service providers’ frequency spectrum and bandwidth/minimal airtime usage for advertising)

2.        Efficient wireless multicast for live or scheduled video contents

3.        Optimal quality for end-users (both fixed and mobile)

4.        Compatible with major emerging wireless broadband technologies such as WiMAX, LTE and WCDMA