Asymmetrical Sub-Sector Antennas for Cellular Capacity
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Solution Overview
Problem
Existing wireless communication systems face limitations in frequency spectrum efficiency and transmission power, leading to co-channel interference and reduced subscriber capacity, especially in densely populated areas where traditional sectorization and cell splitting become inefficient and costly.
Innovation Solution
The introduction of asymmetrical sub-sector antennas that replace traditional sector antennas, allowing for tailored beam patterns to enhance coverage and capacity where needed, reducing handover zones and interference while maintaining network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional sector antennas with symmetrical coverage areas are used, then coverage area is provided, but handover zones become excessively large causing handover overhead and interference
Solution Approach 1:
The patent applies asymmetry by designing sector antennas with non-uniform radiation patterns where different azimuthal directions have different beamwidths. Specifically, the antenna provides narrower beamwidth in directions where sector boundaries create handover zones, and wider beamwidth in directions requiring broader coverage. This asymmetric radiation pattern reduces the area of handover zones between adjacent sectors while maintaining overall coverage area, thereby reducing handover overhead and co-channel interference.
Solution Approach 2:
The patent implements local quality by allowing different parts of the radiation pattern to have different characteristics. The antenna structure enables independent control of beamwidth and gain in different azimuthal directions through techniques such as element weighting, phase shifting, or spatial filtering. This allows the radiation pattern to be optimized locally at sector boundaries to minimize handover zones while maintaining adequate coverage in other directions.
2Productivity
If the number of sectors N is increased to improve spectral efficiency, then subscriber capacity increases, but control channel bandwidth consumption increases without significant capacity gain
Solution Approach 1:
The asymmetric radiation pattern reduces the number of sectors needed to achieve a given capacity target by minimizing handover overhead. With optimized sector boundaries and reduced handover zones, fewer sectors are required to cover the same area efficiently, thereby reducing the number of control channels needed while maintaining or improving subscriber capacity.
3Productivity
If cell splitting is performed to increase network capacity in densely populated areas, then subscriber capacity increases, but network deployment cost and complexity increase
Solution Approach 1:
The patent changes the radiation pattern parameters of existing sector antennas from symmetrical to asymmetric patterns. This parameter change allows existing cell structures to achieve improved capacity in densely populated areas without physical cell splitting or additional infrastructure deployment, thereby increasing network capacity while avoiding the complexity and cost of network expansion.
Data Source
AI summary
A method and apparatus for increasing capacity and performance of a base station for a sectorized cellular wireless network is disclosed in which one of the sector antennas is replaced or supplanted by a novel sub-sector antenna that generates a plurality of asymmetrical sub-sector coverage areas that collectively substantially cover the coverage area of the replaced sector antenna. The use of asymmetrical coverage areas permits the total coverage area to closely approximate the symmetrical sector coverage area without creating excessively large sub-sector handover zones or introducing severe degradation in the network performance. This in turn permits the selective replacement of a single sector antenna rather than the wholesale replacement of all sector antennas in a region, leading to lower transitional costs and the ability to provide a focused approach to capacity planning.