Topology Control for Wireless Networks Using Sectorized Antennas
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Solution Overview
Problem
Current topology control solutions for IEEE 802.11 wireless networks using sectorized antennas rely on simplistic interference models and idealized antenna designs, failing to effectively minimize interference and maximize capacity in dense deployments, as they are primarily evaluated through simulations and do not account for practical considerations such as physical layer capture and sector independence.
Innovation Solution
A measurement-based approach for topology control using low-cost multi-sector antennas, formulated as a quadratic integer program to minimize network interference, which is then reduced to a linear integer program for optimization, allowing for the use of standard Linear Programming solvers and implementation with commodity IEEE 802.11 hardware without modifying the MAC protocol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If sectorized antennas are used to reduce wireless interference through higher spatial reuse, then interference is reduced and capacity is improved, but device complexity and implementation difficulty increase due to requirements for directional MAC protocol modifications
Solution Approach 1:
The patent segments the wireless network into multiple sectors using sectorized antennas, dividing the omnidirectional coverage into directional segments. This segmentation enables spatial reuse by allowing simultaneous transmissions in different sectors, reducing interference while maintaining standard MAC protocol operation without requiring complex protocol modifications.
Solution Approach 2:
The patent introduces a topology control protocol as an intermediary layer between the physical sectorized antennas and the standard MAC protocol. This intermediary handles sector activation and coordination, enabling interference reduction through spatial reuse while preserving compatibility with existing IEEE 802.11 MAC protocols without requiring their modification.
2Productivity
If directional MAC protocols are used to achieve higher spatial reuse by switching between sectors, then spatial reuse is improved, but ease of operation deteriorates due to requirements for fast switching and protocol modifications
Solution Approach 1:
The patent employs dynamic sector activation where sectors are activated or deactivated based on current network conditions and topology requirements. This dynamic approach allows the system to adapt to changing traffic patterns and interference conditions, achieving high spatial reuse when needed while maintaining operational simplicity through automated control rather than manual configuration.
Solution Approach 2:
The patent implements feedback mechanisms where the topology control protocol continuously monitors network conditions, interference levels, and sector performance. Based on this feedback, the protocol automatically adjusts sector activation patterns to optimize spatial reuse while maintaining ease of operation through closed-loop control rather than requiring complex manual protocol modifications.
3Ease of operation
If topology control protocols activate multiple sectors simultaneously at slower time scales, then MAC protocol modifications are avoided, but performance deteriorates due to slower response time
Solution Approach 1:
The patent employs periodic topology control operations where sector activations are updated at appropriate time scales. This periodic approach balances the need for protocol compatibility (avoiding continuous rapid changes that would require MAC modifications) with the need for responsive performance by refreshing sector configurations at intervals that capture network condition changes while maintaining standard protocol operation.
4Device complexity
If simplified interference models and graph theoretic algorithms are used for topology control, then device complexity is reduced, but measurement precision and effectiveness in dense deployments deteriorate
Solution Approach 1:
The patent changes the parameters used in interference modeling from simplified theoretical models to measurement-based parameters derived from actual wireless channel conditions. By using real measurements of signal strength, interference levels, and sector performance from dense deployments, the topology control algorithm achieves higher precision in modeling actual network behavior while maintaining reasonable computational complexity through efficient processing of measurement data.
Data Source
AI summary
The invention concerns a method for optimizing antenna pattern assignment for a first wireless communication device forming a wireless network with at least one second wireless communication device, each of said communication device being equipped with a multi-sector antenna, an antenna pattern being a combination of said antenna sectors, said communication devices being adapted for sending a request and for receiving a response using a current antenna pattern assignment, said method comprising a step of:evaluating by said first communication device a first value;sending by said first communication device to said second communication device a broadcast request comprising said valuereceiving by said first communication device, a response to said broadcast request, said response being sent by said second communication device, said response depending on a second value evaluated by said second device;Switching or not, by said first communication device, to a new antenna sector assignment depending on said response;According to the invention the first value is evaluated by minimizing a first local function according to the received signal strength received by said first communication device having said current antenna pattern assignment and the second value is evaluated by minimizing a second local function according to the received signal strength received by said second communication device for its own current antenna pattern assignment.