Relay User Selection and Downlink Resource Allocation

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Solution Overview

Problem

In relay communication systems, overlapping cell-specific reference signals from base stations and relay stations degrade channel estimation and data demodulation performance, leading to interference and errors in reception demodulation, especially when users are close to the service area of the relay station.

Innovation Solution

A method for relay user selection and downlink resource allocation is introduced, where the base station determines the relay user and allocates resources based on the pattern of the cell-specific reference signal and reception demodulation scheme, including the use of a threshold to account for interference and tolerance items to reduce overlapping signal interference, and instructs the relay station to remove overlapping cell-specific reference signals in specific frequency bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If cell-specific reference signals are transmitted over the entire bandwidth by both base station and relay station, then channel estimation can be performed over the entire bandwidth, but overlapping reference signals cause interference and degrade reception demodulation performance

Engineering Contradiction:

Improvechannel estimation qualityVSAvoidinterference from overlapping reference signals

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The bandwidth is segmented into multiple frequency bands, with each band assigned to either the base station or relay station for reference signal transmission. This prevents overlapping reference signals while maintaining comprehensive channel estimation coverage across the entire bandwidth through coordinated transmission planning.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different frequency bands are allocated different reference signal transmission responsibilities (base station or relay station) based on local conditions. This allows each transmitter to optimize its reference signal transmission in its assigned band without causing interference to the other, while the receiver can perform channel estimation across all bands.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If relay station transmits cell-specific reference signal in the same resource unit as base station, then relay user can perform demodulation, but base station users experience interference when frequency bands overlap

Engineering Contradiction:

Improverelay user demodulation capabilityVSAvoidinterference to base station users

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system segments the frequency spectrum into distinct bands for base station and relay station reference signal transmission. Relay users can still perform demodulation by utilizing reference signals from their serving relay station in the allocated band, while base station users are protected from interference by the frequency separation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The frequency band allocation acts as an intermediary mechanism that enables relay user demodulation capability while simultaneously protecting base station users from interference. By mediating the resource allocation, the system allows both functions to coexist without direct conflict.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If cell-specific reference signal covers entire bandwidth at same power, then all users can use it for channel estimation, but reference signals from relay station corrupt the estimation when adjacent frequency bands overlap

Engineering Contradiction:

Improveuniversal channel estimation capabilityVSAvoidchannel estimation accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The universal channel estimation capability is maintained by segmenting the bandwidth into non-overlapping frequency bands for base station and relay station reference signals. Users can perform channel estimation across the entire bandwidth by combining estimates from both bands, while the segmentation prevents corruption from overlapping signals.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9094093B2Method, apparatus and device for relay user selection and downlink resource allocation

Publication Date: 2015.07.28 ALCATEL-LUCENT USA LNC

AI summary

The present invention proposes a method, apparatus and device for relay user selection and downlink resource allocation in a base station of a relay communication system. Specifically the base station performs relay user selection and downlink resource allocation according to a pattern of a cell-specific reference signal thereof and/or a reception demodulation scheme of a mobile terminal. With the method, apparatus or device according to the invention, it is possible to alleviate and even eliminate influence of overlapping cell-specific reference signals upon the performance of reception demodulation at a user terminal.