TCP-Aware Forward Error Correction for Wireless Networks

This paper studies TCP performance improvement in wireless and heterogeneous networks using Forward Error Correction (FEC) technique driven by TCP semantics. In the proposed scheme, called TCP-aware FEC, the amount of redundancy added to a packet at the sender node corresponds to the level of error protection and is computed as a function of TCP congestion window. The TCP-aware FEC becomes stronger for low congestion window values (experienced after a packet loss is detected), while the amount of added redundancy is reduced for the large window values approaching the capacity of the end-to-end link. The design of TCP-aware FEC adaptability is driven by the mechanics of TCP congestion and flow control mechanisms, and it is based on the notion that link losses become more dangerous when congestion window and sending rate are low. The proposed FEC scheme can be implemented either end-to-end as a part of TCP sender and receiver protocol stacks, or locally, covering the wireless part of the connection only. The performance results obtained through simulations confirm the design assumptions and underline the benefits of the proposed approach with respect to traditional FEC schemes.