OFDM Channel Coding Segmentation for IoT Range Extension
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Solution Overview
Problem
Current wireless communications networks face challenges in balancing energy efficiency and range extension for IoT devices, particularly in IoT applications where devices are battery-powered and require efficient channel coding to minimize energy consumption while maintaining effective range extension.
Innovation Solution
The implementation of enhanced channel coding in wireless communications networks involves applying an outer channel encoder followed by an inner channel encoder, dividing the resulting code bits into two types, and generating OFDM symbols to transmit a packet with both types of bits, allowing receiving nodes to decode payload data efficiently based on channel conditions, thereby extending range without increasing awake time for nodes with good channel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a repetition code is added to extend range, then range is increased, but energy consumption is doubled
Solution Approach 1:
The packet is segmented into two types of OFDM symbols: first type symbols that can be decoded independently, and second type symbols that provide additional redundancy. Receivers with good channel conditions decode only the first type symbols, while receivers with poor channel conditions decode both types, enabling range extension without forcing all receivers to process the entire extended packet.
Solution Approach 2:
Different portions of the packet are assigned different qualities/redundancy levels. The first type OFDM symbols contain essential data that can stand alone, while the second type symbols contain additional redundant information. This local differentiation allows receivers to adapt their decoding behavior to their specific channel conditions, consuming only the energy necessary for their range requirements.
2Length of stationary object
If packet length is doubled for range extension, then range is increased, but awake time is doubled
Solution Approach 1:
The packet is divided into first type OFDM symbols and second type OFDM symbols. Receivers can segment their processing accordingly - those with good channel conditions process only the first type symbols and wake up for a shorter duration, while receivers needing range extension process both types and wake up for the full duration. This segmentation resolves the contradiction by making awake time conditional rather than universal.
Solution Approach 2:
The system introduces dynamic behavior where receivers adapt their packet processing duration based on their channel conditions. Instead of a static packet structure that forces all receivers to wake for the same duration, the dynamic decoding approach allows each receiver to wake and process only as much as needed, converting a static time cost into a dynamic one that matches actual requirements.
3Reliability
If robust channel coding is applied, then reliability is improved, but energy efficiency deteriorates
Solution Approach 1:
Different redundancy levels are applied to different portions of the transmission. The first type OFDM symbols provide baseline reliability for all receivers, while the second type symbols provide enhanced reliability only where needed. This local quality differentiation ensures that energy-efficient receivers don't waste power processing excessive redundancy, while reliability-critical receivers receive the robust coding they need.
Solution Approach 2:
The system applies partial redundancy - not full repetition coding to the entire packet, but rather a selective application of redundant symbols. The first type symbols provide necessary reliability, and the second type symbols provide additional reliability only for receivers that need it. This partial action approach achieves adequate reliability for most receivers without the excessive energy cost of full repetition coding for all.
Data Source
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.