Embedded forward error control technique (EFECT) for low-rate but low latency communications

Abstract

In order to alleviate development cost, many application-oriented wireless networks make use of the off-theshelf wireless standards such as the Bluetooth, IEEE802.15.4 (Zigbee), and IEEE802.11, which are originally developed for personal area networks (PAN) and local area networks (LAN). Examples of such applications are medical monitoring and control. These applications do not require data rates as high as these standards, but instead they require higher reliability with lower latency. As a means to meet such requirements based on these standards, we propose an efficient error control technique named Embedded Forward Error Control Technique (EFECT). This technique enables an additional forward error correction to the existing standards without any additional costs. Some design guidelines based on Reed-Solomon (RS) codes are proposed and, as a specific example, achievable gains by applying the EFECT are studied for the Bluetooth standard.Index Terms-Bluetooth, high reliability, low latency, low-rate data applications, medical real-time life-critical applications.

Exploiting Padding Bits for Improvement of Channel Decoder Performance

“…The two identical RSC encoders are used where the constraint length is 5, and its generator polynomials are expressed as g 0 = (37) 8 for the feed-forward polynomial and g 1 = (21) 8 for the feedback polynomial. out may not be improved by the proposed decoder, while I (2) out gradually improves as L increases. This suggests that the consecutive insertion of the padding bits does not help improving the overall performance as it only leads to local trellis pruning as observed in Fig.…”

“…The blocks denoted by π and π −1 respectively represent an interleaver and a deinterleaver. The final decoded bits are estimated based on the a posteriori LLR Λ (2) in the second MAP decoder. As one can see, the proposed LLR adjustment block can be implemented independently of the MAP decoders, and when L = 0, the decoder is equivalent to the standard iterative decoder without ZP consideration.…”

“…As an approach that directly exploits the padding bits as parity bits, the method called Embedded Forward Error Control Technique (EFECT) is proposed in [2], where, targeting the existing specification such as Bluetooth, it replaces the redundant null bits in the information frame with the party bits of the systematic codes. The resulting system can be seen as an additional outer code of a concatenated code where the existing channel code serves as an inner code without any modification in the PHY layer, and thus the bit-wise reliability information of the inner code cannot be passed to the outer decoder.…”

Adaptive Packet-Level Interleaved FEC for Wireless Priority-Encoded Video Streaming

“…As an example of an existing in-vehicle system, TETRA is the leading wireless cellular system for the emergency services and in combination with TETRA Bluetooth video transmission allows the stream to be transferred within an emergency vehicle (fire-engine, police car, ambulance, etc.). In [19], application-layer FEC is applied at the subpacket-level by replacing padding bits with FEC bits. In a Bluetooth v.1 case study, embedded FEC (using RS coding) is concatenated with built-in data-link layer FEC.…”

“…In a Bluetooth v.1 case study, embedded FEC (using RS coding) is concatenated with built-in data-link layer FEC. Though this form of FEC could be extended to packet-level FEC, the authors of [19] preferred to reduce latency. Therefore, our packet content-dependent scheme could act as an extension to the work in [19].…”