HARQ Bit Mapping and Power Control for Systematic Bit Quality
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Solution Overview
Problem
In high-speed packet transmission schemes like HSDPA and LTE, the Hybrid-ARQ IR scheme's quality of systematic bits significantly influences decoding quality, leading to inefficient retransmissions and throughput issues when systematic bits are deteriorated due to channel conditions, even with high-quality parity bits.
Innovation Solution
A transmitting apparatus and method that control the mapping of systematic and parity bits using incremental redundancy parameters and adjust transmission power based on received quality information to improve systematic bit quality, employing a configuration with a coding section, incremental redundancy parameter controlling section, and transmission power controlling section to optimize bit mapping and power allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If systematic bits are transmitted first and parity bits are transmitted in retransmissions, then the initial transmission structure is simple and follows conventional ARQ procedures, but the received quality of systematic bits deteriorates under poor channel conditions leading to useless retransmissions and throughput deterioration
Solution Approach 1:
The patent inverts the conventional transmission order by transmitting parity bits first in the initial transmission and systematic bits in retransmissions. This inversion ensures that when retransmissions occur, the critical systematic bits receive enhanced protection through power control, preventing quality deterioration and enabling successful decoding.
Solution Approach 2:
The patent dynamically changes transmission parameters by adjusting the power allocation for systematic bits based on channel conditions. When systematic bits are transmitted in retransmissions, their power is controlled to ensure minimum quality thresholds, adapting to fading and interference conditions to maintain reliability.
2Ease of operation
If parity bits are transmitted in retransmissions without power control, then the retransmission procedure follows conventional ARQ, but the systematic bits in retransmissions suffer from channel fading and interference reducing decoding success
Solution Approach 1:
The patent implements feedback-based power control where the receiver measures the quality of received systematic bits and feeds back this information to the transmitter. Based on this feedback, the transmitter adjusts the power allocation for systematic bits in subsequent retransmissions to ensure they meet minimum quality thresholds despite channel variations.
Solution Approach 2:
The patent introduces dynamic power control for systematic bits transmitted in retransmissions. The transmission power is not fixed but is adjusted in real-time based on channel conditions and feedback, making the retransmission process adaptive to fading and interference while maintaining systematic bit quality.
3Reliability
If transmission power is increased for all bits to ensure systematic bit quality, then received quality improves, but transmission power consumption increases and system efficiency decreases
Solution Approach 1:
The patent applies local quality enhancement by selectively increasing power only for systematic bits during retransmissions rather than uniformly increasing power for all transmitted bits. This targeted approach ensures that the critical systematic bits achieve sufficient quality while minimizing overall power consumption and avoiding unnecessary energy expenditure on already-received parity bits.
4Device complexity
If conventional IR scheme is used with fixed power allocation, then the transmission protocol is simple and easy to implement, but throughput performance deteriorates due to useless retransmissions when systematic bits are deteriorated
Solution Approach 1:
The patent introduces feedback mechanisms where the receiver evaluates the quality of received systematic bits and communicates this information back to the transmitter. This feedback enables the transmitter to make informed decisions about power allocation and retransmission strategies, reducing useless retransmissions and improving throughput while maintaining manageable protocol complexity.
Solution Approach 2:
The patent transforms the fixed power allocation scheme into a dynamic one where power levels for systematic bits are adjusted based on channel conditions and reception quality. This dynamic adaptation allows the system to optimize throughput by preventing useless retransmissions while keeping the protocol structure relatively simple through standardized power control procedures.
Data Source
AI summary
A transmitting apparatus and a transmitting method wherein the systematic bit reception quality can be improved and the throughput performance can be improved. An IR parameter control part (101) controls, based on the number of retransmissions, the ratio of systematic bits to parity bits in mapping them to packets, and controls to map a parity bit to an initially transmitted packet, while mapping a systematic bit to a retransmitted packet. An encoding part (102) generates the systematic bits and parity bits and maps them to the packets in accordance with the IR parameters. A transmission power calculating part (105) calculates, based on reception quality information of the initially transmitted packet fed back from a receiving end, the transmission power of the transmitted packet to which the systematic bit is mapped. A transmission power control part (106) controls the transmission power of the retransmitted packet such that it is equal to the transmission power as calculated by the transmission power calculating part (105).