Inter-cell interference avoidance via codebook vector selection
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Solution Overview
Problem
In wireless communication networks, inter-cell interference between base stations serving nearby user equipment (UEs) using the same frequency band constrains network throughput, as UEs receive unintended signals from neighboring base stations, leading to low signal-to-interference-and-noise ratios (SINR) and reduced cell-edge throughput.
Innovation Solution
A subscriber station equipped with multiple receive antennas and a processor performs channel estimation to generate and transmit compressed feedback information, including threshold and codebook vector information, to help base stations select codebook vectors that minimize interference, thereby avoiding interference in communications between the serving and interfering base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If base stations use the same frequency band for downlink transmission to nearby UEs, then network coverage and service capacity are improved, but inter-cell interference increases and throughput is constrained
Solution Approach 1:
The patent changes the codebook vector parameters at the transmitting base station based on feedback from the subscriber station. The feedback includes interference level measurements and recommended codebook vectors, allowing the base station to adjust transmission parameters to minimize interference while maintaining throughput
Solution Approach 2:
The patent implements a feedback mechanism where the subscriber station measures interference from neighboring base stations and sends compressed feedback information to the serving base station. This feedback includes threshold information and codebook vector recommendations that enable the base station to adapt its transmission to avoid causing interference
2Ease of manufacture
If base stations transmit using standardized codebooks, then device complexity is reduced and ease of manufacture is improved, but interference avoidance capability deteriorates
Solution Approach 1:
The patent allows base stations to use standardized codebooks as a base, but introduces dynamic parameter changes based on feedback. The codebook vector selection is adjusted by selecting specific vectors from the standardized codebook that minimize interference, rather than using fixed predetermined vectors
Solution Approach 2:
The subscriber station performs self-service by measuring interference levels and autonomously determining recommended codebook vectors. The station compresses and sends this information to the base station, enabling the base station to self-adjust its transmission parameters without complex centralized coordination
3Measurement precision
If subscriber stations report detailed channel state information, then base stations can optimize transmission accuracy, but feedback overhead and loss of information increase
Solution Approach 1:
The patent extracts only the essential information needed for interference avoidance from the full channel state information. Instead of reporting complete CSI, the subscriber station identifies and reports only the threshold information and codebook vector recommendations that are critical for preventing inter-cell interference
Solution Approach 2:
The patent applies different levels of information reporting quality to different purposes. For interference avoidance, only compressed feedback with threshold and codebook vector information is sent. For other transmission optimizations, full channel state information can be reported, allowing each feedback channel to have appropriate quality levels
Data Source
Figure 1A~1B
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AI summary
A system and method for inter-cell interference avoidance. An apparatus of a base station, BS, in a wireless communications network comprising a plurality of BSs, the apparatus comprising a receiver configured to receive feedback information from at least one user equipment, UE, wherein the feedback information comprises at least one of two sets and wherein a first set of the two sets corresponds to a recommend set of codebook information that will cause an interference in received signals of the at least one UE from at least one serving BS to be less than a threshold and wherein a second set of the two sets corresponds to a restricted set of codebook information that will cause an interference in received signals of the at least one UE from the at least one serving BS to be greater that the threshold, a controller configured to identify the at least one of two sets and select codebook vector information based on the identified at least one set in order to avoid interference.