Abstract

Multicast services are well supported by geostationary satellites as a result of their broadcasting capability over large coverage areas. However, in this context the reliability management must be accurately analysed, since satellite resources are expensive and link quality degrades significantly during adverse weather conditions. In this paper, we show that the conventional layered approach of reliability management can be adapted and optimized for multicast over satellite. Our proposal consists in removing, at low layers, most of packet discardings, and introduces the MPHP mechanism which protects protocol headers. At transport level, for full reliability, we adapt conventional erasure decoding used with packet-level FEC and on this basis we propose a hybrid-ARQ protocol with a specific error and erasure decoding. The performance analysis shows that applications like real-time multimedia delivery using UDP-lite for partial reliability can benefit from a reduced error rate, and applications like massive file transfers requiring full reliability are less demanding in terms of network resources.

Keywords: Multicast; Satellite; FEC; Hybrid-ARQ; Header protection

Article Outline

1. Introduction and problem statement

2. Conventional reliability management in IP multicast over DVB-S

2.1. Reliability management at low layers

2.2. Reliability management at transport layer

2.2.1. Fully reliable delivery

2.2.2. Partially reliable delivery

2.3. Limits of conventional reliability management

3. Cross-layer reliability management for partially reliable multicast satellite service

3.1. Limited packet discarding

3.2. Multi-protocol header protection (MPHP)

3.3. Packet loss rate evaluation

4. A type II Hybrid-ARQ transport protocol for fully reliable multicast satellite service

4.1. Hybrid-ARQ scheme

4.2. Interleaving

4.3. FEC adaptation

4.3.1. Decoding

4.3.2. Implementation issues

4.3.2.1. Few or no extra parity data received

4.3.2.2. MPHP coverage

4.4. Redundant transmissions management

4.5. Implementation

4.5.1. Types of message and protocol operations

5. Performance evaluation

6. Concluding remarks and future work

References

Vitae