Single H-ARQ Process for MIMO Channel Adaptation

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Solution Overview

Problem

The complexity and inefficiency of managing Hybrid ARQ (H-ARQ) in Multiple Input Multiple Output (MIMO) antenna systems, where each antenna requires separate H-ARQ processes, increasing hardware and software complexity and reception time, and varying channel quality necessitates different transmission rates and sub-block sizes.

Innovation Solution

Implementing a single H-ARQ process across all antennas using a single FEC coder, distributing coded information based on channel conditions, and recalculating sub-blocks for retransmissions to match current channel conditions, allowing flexible sub-block transmission through various antennas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If each antenna performs its own specific H-ARQ procedure in MIMO systems, then the system can handle varying channel conditions for each antenna, but the hardware and software complexity significantly increases

Engineering Contradiction:

Improvechannel condition adaptationVSAvoidhardware and software complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple per-antenna H-ARQ processes into a single centralized H-ARQ process that manages all antennas. The transmitter includes a single H-ARQ process that maintains one code block and its associated soft bits, eliminating the need for separate H-ARQ processes for each antenna while still enabling flexible distribution of code block parts across multiple antennas based on channel conditions

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single H-ARQ process is designed to be universal, handling code block transmission across multiple antennas with varying channel conditions. It maintains a single code block and can dynamically allocate parts of this code block to different antennas based on current channel quality, making the system adaptable without requiring antenna-specific H-ARQ processes

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If separate H-ARQ processes are implemented for each antenna in MIMO systems, then each antenna can be optimized for its channel conditions, but the reception time of packets at the destination increases

Engineering Contradiction:

Improveantenna-specific optimizationVSAvoidpacket reception time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

By combining multiple antenna-specific H-ARQ processes into a single unified process, the patent reduces the number of separate process management operations. The single H-ARQ process maintains one code block and can efficiently manage retransmissions across multiple antennas, reducing the overall reception time compared to coordinating multiple independent processes

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If different coding is applied to each sub-block transmitted on separate antennas, then the system can adapt to varying channel qualities, but the signaling information required increases significantly

Engineering Contradiction:

Improvechannel quality adaptationVSAvoidsignaling information overhead

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent applies local quality by distributing different parts of a single code block to different antennas based on their specific channel conditions. Each antenna transmits a portion of the code block optimized for its channel state, but all parts belong to the same code block managed by the single H-ARQ process, avoiding the need for separate coding schemes and reducing signaling overhead

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The code block is segmented into parts that can be distributed across multiple antennas. The single H-ARQ process divides the code block into transmittable units and allocates them to appropriate antennas based on channel conditions, maintaining coding efficiency while adapting to local channel variations without requiring separate coding for each antenna

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS7532600B2Method and system for using hybrid ARQ in communication systems that use multiple input multiple output antenna systems

Publication Date: 2009.05.12 NOKIA OF AMERICA CORP

AI summary

A method and system for using one H-ARQ process in communication systems having a Multiple Input Multiple Output antenna system. Information to be transmitted is first coded using a particular coding scheme and having a particular base coding rate. The coded information is then divided into groups of sub-blocks of coded information. Each group of sub-blocks of coded information contains one or more sub-blocks where the number of sub-blocks in a group is determined from current channel conditions of an antenna through which the group is to be transmitted. The groups are then rate matched and modulated based on the current channel conditions and transmitted through one or more antennas. For any retransmissions, the same coded information is used and is divided into groups of sub-blocks of coded information where at least one new group is associated with one of the plurality of antennas; the number of sub-blocks of coded information in a new group is based on current channel conditions experienced by the associated one antenna. Each group of sub-blocks is again rate matched and modulated before transmission. The rate matching and modulation parameters for any group of sub-blocks are determined by the channel conditions of the antenna through which that particular group is to be transmitted.