Radio Resource Allocation in Fixed Wireless Access Networks
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Solution Overview
Problem
Modern wireless communication networks face challenges in efficiently allocating radio resources in fixed wireless access networks, particularly in reducing signalling overhead and improving spectral efficiency compared to mobile networks.
Innovation Solution
A method and scheduler for allocating radio resources in a fixed wireless access network, which involves determining whether a subscriber module is suitable for frequency re-use or frequency partition based on specific criteria, and then allocating resources accordingly, with a two-stage decision process to reduce signalling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency re-use factor of 1 is used for all users, then spectral efficiency is improved, but interference between adjacent cells increases causing degradation in communication quality for users at cell boundaries
Solution Approach 1:
The patent applies different frequency re-use factors to different spatial locations within the network. Users at cell boundaries experience lower frequency re-use (higher reuse factor) to reduce interference, while users in inner regions experience higher frequency re-use (lower reuse factor) to maximize spectral efficiency. This local differentiation resolves the contradiction by optimizing both communication quality and spectral efficiency for different spatial zones.
Solution Approach 2:
The patent dynamically adjusts the frequency re-use factor based on user equipment's SINR measurements and reported CQI values. The base station adapts the frequency allocation in real-time according to channel conditions, allowing the system to transition between different re-use factors (1, 3, or higher) depending on the user's location and signal quality, thereby resolving the static contradiction between spectral efficiency and communication quality.
2Reliability
If higher frequency re-use factor is used for users with lower SINR, then communication quality is improved, but spectral efficiency decreases due to reduced frequency utilization
Solution Approach 1:
The patent implements local quality optimization by assigning higher frequency re-use factors specifically to users experiencing poor channel conditions (low SINR, typically at cell boundaries), while maintaining lower re-use factors for users with good channel conditions. This spatially-selective approach ensures that communication quality is improved where needed without unnecessarily sacrificing spectral efficiency in regions where it can be maintained.
Solution Approach 2:
The patent changes the frequency re-use parameter dynamically based on the SINR parameter. When SINR falls below a threshold, the system increases the frequency re-use factor to improve communication quality. When SINR is above the threshold, the system decreases the re-use factor to maximize spectral efficiency. This parameter-based adaptation resolves the contradiction by linking resource allocation to actual channel conditions.
3Reliability
If robust modulation and error correction schemes are used for users at cell boundaries, then communication reliability is improved, but data throughput decreases
Solution Approach 1:
The patent dynamically selects modulation and error correction schemes based on the user's SINR and reported CQI. Instead of always using robust but low-throughput schemes for cell boundary users, the system adapts the modulation order and coding rate to match the actual channel conditions, achieving the minimum required reliability while maximizing throughput within those constraints.
Solution Approach 2:
The patent changes modulation and coding parameters based on the SINR parameter. For users with poor channel conditions, more robust schemes are selected to ensure reliability. For users with good channel conditions, less robust but higher-throughput schemes are selected. This parameter adaptation resolves the contradiction by optimizing both reliability and throughput according to actual channel quality.
4Reliability
If directional antennas are used by subscriber modules, then signal gain and interference rejection are improved, but system complexity increases due to precise alignment requirements
Solution Approach 1:
The patent enables subscriber modules to autonomously determine their SINR and report CQI values to the base station without requiring complex external alignment systems. The directional antennas self-adjust to provide signal gain and interference rejection based on the fixed installation geometry, while the intelligent resource allocation algorithm compensates for any misalignment by adapting frequency and power allocation, thereby reducing the need for precise manual alignment.
Data Source
AI summary
Radio resource is allocated to a subscriber module in a fixed wireless access cellular wireless system comprising an access point and a plurality of subscriber modules at static locations, each subscriber module having a directional antenna aligned with the access point, and the area of coverage of the access point having a plurality of sectors. It is determined, at a first repetition rate, whether the subscriber module is suitable for frequency re-use based on a first criterion. If so, radio resource is allocated for communication to the subscriber module that is also allocated to adjacent sectors. Otherwise, a measure of quality of communication on a channel between the subscriber module and the access point is determined, more frequently than the first repletion rate, and radio resource is allocated for communication to the subscriber module, that is also allocated to an adjacent sector, dependent on the measure meeting a second criterion.