Reverse Link Feedback Multiplexing Using Code Division Masks

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Solution Overview

Problem

In wireless communication systems, particularly those employing CDMA protocols, there is a need to efficiently multiplex reverse link feedback channels to support multiple forward link frequencies, as the number of forward link channels often exceeds the number of reverse link channels, leading to challenges in managing bandwidth and reducing interference.

Innovation Solution

The method involves assigning reverse link frequencies to mobile stations and using code division multiplexing to combine multiple reverse link feedback channels on a single reverse link frequency, employing different long code masks for each forward link frequency to separate and transmit feedback information effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple reverse link feedback channels are assigned to support multiple forward link frequencies, then the system can support more forward link channels, but the reverse link bandwidth requirement increases

Engineering Contradiction:

Improvesupport for multiple forward link channelsVSAvoidreverse link bandwidth

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent combines multiple reverse link feedback channels (DRC channels for different forward link frequencies) into a single reverse link frequency by using code division multiplexing. Different feedback channels are assigned different long code masks, allowing them to be transmitted simultaneously on the same frequency without interference, thus reducing reverse link bandwidth requirements while maintaining support for multiple forward link channels.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from frequency-domain separation to code-domain separation. Instead of assigning separate frequencies for each feedback channel, the invention uses different long code masks (code dimension) to separate multiple feedback channels transmitted on the same frequency, effectively adding a code dimension to the transmission system.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If separate reverse link frequencies are used for each forward link frequency, then interference between channels is reduced, but the system complexity and resource allocation becomes more complex

Engineering Contradiction:

Improveinterference between channelsVSAvoidchannel management complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges multiple reverse link feedback channels onto a single reverse link frequency, reducing the number of frequency resources to manage. By using orthogonal long code masks, the system maintains low interference between channels while simplifying frequency allocation and channel management.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces long code masks as an intermediary mechanism to separate and identify different feedback channels. These code masks act as unique identifiers that allow the base station to distinguish and separately process feedback from different forward link frequencies even when transmitted on the same reverse link frequency.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If code division multiplexing is used to combine multiple feedback channels on a single frequency, then bandwidth efficiency improves, but the processing complexity at the receiver increases

Engineering Contradiction:

Improvebandwidth efficiencyVSAvoidreceiver processing complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by assigning specific long code masks to different feedback channels in advance, before transmission occurs. This pre-assignment of orthogonal codes allows the receiver to efficiently separate channels using simple correlation operations, rather than requiring complex real-time processing.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for efficient use of bandwidth by multiplexing multiple reverse link feedback channels on a single frequency, reducing interference and enhancing communication efficiency in multicarrier systems.

Implementation Method 1

code division multiplexing a plurality of the reverse link feedback channels on the reverse link frequency

Methodology Applied

Scientific EffectCode division multiplexing:

Data Source

PatentUS8868118B2Multiplexing on the reverse link feedbacks for multiple forward link frequencies

Publication Date: 2014.10.21 QUALCOMM INC

AI summary

The present patent application comprises a method and apparatus for multiplexing reverse link feedback channels on a single reverse link frequency supporting multiple forward link frequencies for forward link channels, comprising assigning the reverse link frequency to a mobile station, assigning one or more of the forward link frequencies to the reverse link frequency, and code division multiplexing a plurality of the reverse link feedback channels on the reverse link frequency.