Distributed RRM Resource Allocation via Event-Triggered Signaling
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Solution Overview
Problem
In distributed Orthogonal Frequency Division Multiple Access (OFDMA) wireless communication networks, frequent message exchanges between Base Stations lead to high signalling load and inability to avoid Co-Channel Interference (CCI) due to lack of information about reserved or preferred subchannels.
Innovation Solution
Implementing a method where Base Stations send RRM Request messages with a new trigger event to notify neighbors of resource allocation changes, allowing them to send Spare Capacity Report messages only when necessary, and including a 'Permutation Zone Subchannels Bitmap' to prevent reuse of same radio resources, thereby reducing signalling load and CCI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If frequent message exchanges are implemented to maintain updated resource allocation information, then information freshness is improved, but signalling load increases
Solution Approach 1:
The patent implements event-triggered periodic action where RRM Request messages are sent only when specific events occur (resource allocation changes, interference detection, or periodic updates), rather than continuous frequent exchanges. This reduces signalling load while maintaining information freshness when actually needed.
Solution Approach 2:
The patent introduces a trigger event mechanism that changes the behavior of message exchange based on parameter states. When resource allocation parameters change or interference thresholds are exceeded, the system transitions from idle to active message exchange, optimizing the balance between information freshness and signalling overhead.
2Device complexity
If distributed RRM is implemented without centralized coordination, then system complexity is reduced, but Co-Channel Interference cannot be avoided
Solution Approach 1:
The patent implements feedback mechanisms where Base Stations exchange RRM Request and Response messages to share resource allocation information. This distributed feedback allows each BS to adjust its resource allocation based on neighbor BS information, avoiding CCI while maintaining distributed architecture without centralized coordination complexity.
Solution Approach 2:
The patent uses RRM Request and Response messages as intermediaries to facilitate communication between distributed Base Stations. These standardized message structures enable information exchange about resource allocation, allowing distributed BSs to coordinate resource usage and avoid interference without requiring a centralized controller.
3Adaptability or versatility
If standardized RRM primitives are used for information exchange, then interoperability is improved, but ability to convey detailed resource allocation information is limited
Solution Approach 1:
The patent segments the resource allocation information into structured fields within standardized RRM primitives. The RRM Request and Response messages contain specific information elements such as resource block indicators, allocation patterns, and interference metrics, allowing detailed information to be conveyed through standardized segmented fields that maintain interoperability.
Data Source
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AI summary
A method for improving distributed resource allocation in OFDMA based wireless communication networks such as WiMAX IEEE 802.16 for either fixed or mobile subscriber stations SSs (90', 91') is executed by neighbour Base Stations BSs (100', 101') serving the SSs. Each BS controls the allocation of respective permutation zones and radio resources encompassing different radio subchannels within each permutation zone. In this task the BS avails of RRM primitives and instances of a NCMS functionality promoting direct BS-to-BS communication, which can be exploited in a distributed RRM profile. A BS playing the role of RRC sends to Neighbour BSs a unique RRM Request (102') for receiving event-driven Spare Capacity Reports. Among driving events, "Change of Radio Resources Allocation" is included. Neighbour BSs, at every allocation change is detected, send to the requester BS a Spare Capacity Report (104') including a Bitmap indicating subchannels used for transmission in each Permutation Zone. In order to eliminate Co-Channel Interference CCI, the requester BS avoids using same subchannels already indicated in the received Bitmap (fig.5).