Relay Station Spectrum Aggregation for Interference Reduction
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Solution Overview
Problem
Current relay station technologies in wireless communication networks face inefficiencies due to half-duplex FDD or TDD operations, leading to reduced system efficiency, frame structure modifications, difficulties in supporting synchronous HARQ, and monitoring all mobile stations.
Innovation Solution
Allocating non-overlapping frequency sub-bands for communication links between base stations, relay stations, and mobile stations, allowing simultaneous reception and transmission within these sub-bands to increase bandwidth and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If half-duplex FDD or TDD operation is used in relay stations, then self-interference between transmitter and receiver is avoided, but system efficiency is reduced
Solution Approach 1:
The available frequency spectrum is segmented into multiple non-overlapping sub-bands. The relay station is allocated a first frequency sub-band for receiving signals from the base station and a third frequency sub-band for transmitting signals to mobile stations. This frequency segmentation enables simultaneous reception and transmission operations without self-interference, resolving the contradiction between reliability and productivity.
2Reliability
If half-duplex operation is used, then self-interference is avoided, but frame structure modification is required
Solution Approach 1:
The solution moves from time-domain separation (TDD) or frequency-domain separation (FDD) to a combined approach using non-overlapping frequency sub-bands. By allocating specific sub-bands for reception and transmission simultaneously, the patent eliminates the need for frame structure modifications while avoiding self-interference, thus resolving the contradiction between reliability and device complexity.
3Reliability
If half-duplex operation is used, then self-interference is avoided, but synchronous HARQ support becomes difficult
Solution Approach 1:
The frequency spectrum is segmented into dedicated sub-bands for different communication links. The relay station uses a first frequency sub-band for receiving downlink signals and a third frequency sub-band for transmitting uplink signals simultaneously. This frequency division enables synchronous HARQ operations by maintaining continuous bidirectional communication without time slot restrictions, resolving the contradiction between reliability and ease of operation.
4Reliability
If half-duplex operation is used, then self-interference is avoided, but monitoring all mobile stations becomes difficult
Solution Approach 1:
The available bandwidth is segmented into multiple non-overlapping frequency sub-bands that are allocated to different communication links. The relay station simultaneously receives on the first frequency sub-band and transmits on the third frequency sub-band, enabling continuous monitoring of multiple mobile stations without self-interference. This frequency segmentation resolves the contradiction between reliability and ease of operation for mobile station monitoring.
Data Source
AI summary
International Mobile Telecommunications (IMT) Advanced technology, also known as 4th Generation (4G) targets to support up to 100 MHz BW. LTE currently supports single carrier bandwidths of up to 20 MHz. The present application describes a multi-carrier approach in which some embodiments of the invention provide a simple solution of aggregating multiple single carrier bandwidths to obtain a wider bandwidth (>20 MHz). Such an approach may extend Long Term Evolution (LTE) bandwidth to greater than that provided by a single carrier, yet maintain full backward compatibility with technologies that predate 4G technology and utilize smaller, single carrier bandwidths. More generally, embodiments of the invention can apply to other communication standards than only LTE.