Ideal Forward Error Correction Codes for High-Speed Rail Multimedia Communications

In recent years, application-layer forward error correction (AL-FEC), particularly rateless AL-FEC, has received much attention due to its superior performance in both transmissional and computational efficiency. Rateless AL-FEC (e.g., Raptor code or Luby transform (LT) code) can protect a large data block with an overhead somewhat close to ideal codes. In the meantime, its data processing rates of both encoding and decoding are quite efficient even in software implementations. However, we found that conventional rateless AL-FEC schemes may not be the best candidates when considering streaming over Worldwide Interoperability for Microwave Access (WiMAX) networks for high-speed rail reception in Taiwan. In this paper, we propose a new ideal AL-FEC scheme based on the Chinese remainder theorem (CRT) to facilitate streaming service delivery for high-speed rail reception. The proposed scheme can support the rateless property, but it requires less transmission overhead than conventional rateless codes. Although it requires higher computational cost than conventional rateless codes, the cost is affordable for commodity laptops. In addition to measuring the FEC computation, storage, and decoder overhead, we also evaluate its performance in an emulation environment for simulating high-speed rail reception over WiMAX networks. The emulation result shows that the proposed scheme can achieve the same error protection as Raptor codes, but it requires less transmission overhead, which is suitable for protecting data transmission over bandwidth-limited high-mobility erasure channels.