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 HSUPA, the quality of systematic bits significantly influences decoding quality, leading to inefficient retransmissions and reduced throughput 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 and throughput, by mapping parity bits in initial transmission units and systematic bits in retransmission units, and adjusting transmission power accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If systematic bits are transmitted first in the IR scheme, then the transmission structure is simple and parity bits can be transmitted in retransmissions, but the received quality of systematic bits deteriorates under poor channel conditions leading to useless retransmissions

Engineering Contradiction:

Improvetransmission structureVSAvoidreceived quality of systematic bits

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent inverts the conventional transmission order by transmitting parity bits first instead of systematic bits. This inversion allows the system to protect the more critical systematic bits through enhanced power control in retransmissions, resolving the contradiction between simple structure and reliable reception under fading conditions.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent dynamically changes transmission parameters including power allocation and mapping patterns based on channel conditions. By adjusting the ratio of systematic to parity bits and modifying power distribution according to received quality feedback, the system maintains reliability while adapting to varying channel states.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If systematic bits are transmitted with fixed power, then power control is simple, but throughput performance deteriorates when channel conditions fade

Engineering Contradiction:

Improvepower control mechanismVSAvoidthroughput performance

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent implements feedback-based power control where the receiving side measures received quality of systematic bits and feeds back this information to the transmitting side. This feedback loop enables dynamic adjustment of transmission power for systematic bits, ensuring adequate received quality while improving throughput under fading conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent transitions from fixed power control to dynamic power control where transmission parameters are continuously adjusted based on channel conditions. The system dynamically modifies power allocation ratios and mapping patterns to optimize throughput while maintaining simple operational procedures.

Inventive Principle:

Principle #15Dynamics

3Reliability

If parity bits are transmitted in retransmissions, then incremental redundancy is achieved, but the number of retransmissions increases when systematic bits are deteriorated

Engineering Contradiction:

Improveerror correction capabilityVSAvoidnumber of retransmissions

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary protection of systematic bits by transmitting them with enhanced power control and optimized mapping before retransmission is needed. This preliminary action ensures that systematic bits arrive with sufficient quality, reducing the need for additional retransmissions while maintaining incremental redundancy benefits.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7844881B2Transmitting apparatus and transmitting method

Publication Date: 2010.11.30 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

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).