Systematic Inner Coding for OFDM Packets With Early Decoding
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Solution Overview
Problem
Current wireless communications networks face challenges in balancing energy efficiency and range extension for Internet of Things (IoT) devices, particularly in link adaptation and channel coding, where robust modulation and coding schemes consume excessive energy and are not adaptable to sporadic device activity, and existing solutions like repetition codes increase energy consumption without addressing efficient decoding for devices with good channel conditions.
Innovation Solution
Implementing a method that uses systematic inner encoding in transmitting nodes to generate OFDM symbols, allowing receiving nodes to decode payload data from either the initial set of systematic bits or additional parity bits, enabling extended coverage range while providing energy-efficient decoding for nodes not needing range extension, by splitting channel coding into outer and inner encoders and transmitting these sets separately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If repetition code is added to extend range, then coverage range is improved, but energy consumption increases
Solution Approach 1:
The patent segments the coded bits into systematic bits and parity bits, transmitting systematic bits first. Receiving nodes with good channel conditions can decode using only systematic bits, while nodes needing range extension receive additional parity bits. This segmentation allows differentiated energy consumption based on actual decoding needs.
Solution Approach 2:
The patent applies local quality by providing different levels of coding protection to different receiving nodes based on their channel conditions. Nodes with good channel conditions receive minimal protection (systematic bits only), while nodes with poor conditions receive full protection (systematic + parity bits), optimizing energy efficiency for each local situation.
2Reliability
If robust modulation and coding schemes are used, then reliability is improved, but energy consumption increases
Solution Approach 1:
The patent implements partial action by transmitting only the necessary coding bits for each receiving node's needs. Instead of always transmitting full redundancy for maximum reliability, the system transmits systematic bits first and only adds parity bits when needed, achieving adequate reliability with minimal energy consumption for each node.
Solution Approach 2:
The patent introduces dynamics by making the transmission adaptive to channel conditions. The receiving node dynamically determines whether to request additional parity bits based on successful decoding of systematic bits alone, allowing the system to adjust the level of reliability protection in real-time based on actual channel quality.
3Area of stationary object
If packet length is doubled for range extension, then coverage range is improved, but transmission time increases
Solution Approach 1:
The patent segments the extended packet into two parts: systematic bits transmitted first, followed by optional parity bits. This segmentation allows receiving nodes with good channel conditions to decode successfully using only the first part, effectively reducing their transmission time despite the overall packet being extended for range coverage.
Solution Approach 2:
The patent applies preliminary action by transmitting systematic bits first, which contain sufficient information for decoding under good channel conditions. This preliminary transmission allows early decoding success for nodes with good channel quality, avoiding the need to wait for the full extended packet to be transmitted.
Data Source
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AI summary
A Transmitting Node (TN) 102 and a method therein for providing enhanced channel coding of a packet transmitted in a communications network 100. The TN applies, to payload data, an outer channel encoder resulting in a plurality of outer code bits. Further the TN applies an inner channel encoder to the plurality of outer code bits. Furthermore, the TN divides resulting code bits of the inner channel encoder into a first group and one or more second groups. Yet further, the TN generates a first set of OFDM symbols carrying at least a part of the first group, and second sets of OFDM symbols carrying at least a part of the one or more second groups. The TN transmits a packet comprising the first set of OFDM symbols followed by the second sets of OFDM symbols, whereby an enhanced channel coding of the transmitted packet is provided. A receiving node (RN) 104 and a method therein for enabling enhanced channel decoding of a packet transmitted in a wireless communications network 100, wherein a TN and the receiving node RN are configured to operate in the wireless communications network. The RN receives, from the TN, parts of a packet, which packet comprises a first set of Orthogonal Frequency-Division Multiplexing, OFDM, symbols followed by one or more second sets of OFDM symbols, wherein the first set of OFDM symbols carries at least a part of a first group of bits comprising bits of a first type, and wherein the one or more second sets of OFDM symbols carry at least a part of one or more second groups of bits comprising bits of a second type. When payload data is decodable from received parts comprising the first set of OFDM symbols, the RN decodes the payload data from the first set of OFDM symbols. When payload data is unsuccessfully decoded from received parts comprising the first set of OFDM symbols, the RN decodes the payload data from the first set of OFDM symbols and the one or more second sets of OFDM symbols, and the RN stops receiving parts of the packet when the payload data is decoded. (Fig. 1)