Cluster-Based Spectrum Allocation for CBSD Networks
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Solution Overview
Problem
In CBRS networks, there is a significant under-utilization of spectrum due to individual CBSDs being assigned more spectrum than they can utilize, leading to inefficiencies and increased control signaling overhead, especially when dealing with a large number of devices.
Innovation Solution
Grouping CBSDs into clusters to determine and communicate their collective spectrum needs to the SAS, allowing for more efficient spectrum allocation and distribution within the cluster, thereby reducing the need for extensive signaling between CBSDs and the SAS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spectrum is assigned to each individual CBSD, then each CBSD receives dedicated spectrum resources, but spectrum utilization becomes inefficient and control signaling overhead increases
Solution Approach 1:
Multiple CBSDs are grouped into a cluster and treated as a single entity for spectrum allocation purposes. The cluster collectively receives spectrum grants from the SAS, allowing shared utilization of spectrum resources among member CBSDs. This merging approach resolves the contradiction by improving spectrum utilization efficiency while maintaining reliable allocation through centralized cluster-level management.
Solution Approach 2:
The spectrum allocation mechanism is designed to serve multiple CBSDs simultaneously through a universal cluster-based approach. A single spectrum grant to a cluster can be utilized by multiple CBSDs within that cluster, enabling the system to adapt to varying traffic demands across different devices. This multi-functionality improves productivity while maintaining allocation reliability.
2Productivity
If spectrum allocation signaling frequency is increased, then spectrum utilization efficiency improves, but control signaling overhead becomes impractical for large numbers of CBSDs
Solution Approach 1:
Multiple CBSDs are merged into a single cluster entity that communicates with the SAS. Instead of each CBSD individually requesting and reporting spectrum needs, the cluster collectively manages spectrum allocation. This significantly reduces the quantity of control signaling messages between CBSDs and SAS while maintaining efficient spectrum utilization through coordinated cluster-level resource sharing.
Solution Approach 2:
The cluster acts as an intermediary between individual CBSDs and the SAS. Internal cluster coordination handles resource distribution among members, reducing the need for frequent individual signaling to the SAS. This intermediary approach maintains productivity by enabling efficient resource allocation while dramatically reducing control signaling overhead to practical levels.
3Adaptability or versatility
If more CBSDs are deployed in the network, then network coverage and capacity improve, but spectrum waste increases due to under-utilization
Solution Approach 1:
As more CBSDs are deployed and grouped into clusters, the cluster-based allocation enables efficient sharing of spectrum resources across all members. This merging approach allows the network to expand adaptively by adding more CBSDs to existing clusters or creating new clusters, while the shared spectrum pool ensures that resources are utilized efficiently across the expanded network, preventing spectrum waste even as network size increases.
Data Source
AI summary
A first citizens broadband radio service device (CBSD), which is part of a first cluster of CBSDs, determines total needed spectrum for the first cluster, based on a determination of its own spectrum needs and received information from other CBSDs in the cluster communicating their determined spectrum needs. The first CBSD communications the total spectrum needs for the first cluster to a spectrum access system (SAS). The first CSBD receives a spectrum allocation for the first cluster from the SAS, which allocates spectrum on a per cluster basis. The first CSBD selects a first portion of spectrum for itself from the received allocation and communicates the SAS first cluster spectrum allocation and the first CSBD selected first portion of spectrum to a second CBSD in the cluster. The second CBSD determines the remaining spectrum of the SAS allocation and selects a second portion of spectrum from remaining spectrum for itself.