Rateless802.11: Architecture Design And Performance Optimization

In conventional 802.11, MAC protocol data units (MPDUs) that a receiver fails to decode will be simply discarded even when only a very few bits are corrupted. This makes conventional 802.11 hardly work when the channel fading or the interference is very severe. In this paper, we propose Rateless802.11, a novel scheme that is fully compatible with common commodity 802.11 devices, which can be used as a complement of 802.11 used in terrible channels. By concatenating LT codes with 802.11 convolutional codes, Rateless802.11 can introduce redundancy properly without the need of accurate channel status estimation, and exploit the uncorrupted bits of MPDUs adequately. To improve the decoding performance as well as reducing the decoding delay, we introduce an integrated decoder (IntBP) in Rateless802.11, which decodes convolutional codes and LT codes compactly and can be performed in an incremental manner. Evaluations based on numerical simulation and driven by universal software radio peripheral (USRP) captured real trace show that IntBP can dramatically improve decoding reliability compared with natural serial decoding approaches and compared with state-of-the-art solutions, throughput of 802.11 in terrible channels can be improved many times by Rateless802.11.