Virtual Base Station Controller for Local Switching
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Solution Overview
Problem
Conventional MSC equipment struggles to manage and configure multiple types of base station subsystems, particularly in scenarios with alternative BSS configurations like microcell and picocell, and incurs high backhaul data costs due to inefficient data communication over expensive links like satellite connections.
Innovation Solution
A wireless system with a virtual base station controller (VBSC) that appears as a single BSC to the MSC, enabling local switching within base station subsystems and optimizing backhaul communication by using IP networks and media gateways to route calls within the same routing zone, thereby reducing the need for data to be sent to the MSC for switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional MSC equipment is used to manage multiple types of base station subsystems (macrocell, microcell, picocell), then the network can support diverse BSS configurations, but the MSC becomes difficult to configure and manage since it cannot be configured to work with multiple different types of BSS equipment at the same time
Solution Approach 1:
A gateway node is introduced as an intermediary between the MSC and multiple BSS types. The gateway translates and adapts signaling between different BSS configurations and the MSC, allowing the MSC to interact with a standardized interface while supporting diverse BSS equipment types behind the gateway.
Solution Approach 2:
The gateway is designed with multi-functional capabilities to handle different BSS types (macrocell, microcell, picocell) through a single interface. It performs multiple functions including signaling translation, call routing, and configuration management for various BSS configurations, eliminating the need for separate MSC configurations for each BSS type.
2Reliability
If all call data is communicated over the backhaul link to the MSC for switching, then the MSC can handle all switching operations, but the amount of data transmitted over expensive backhaul links (such as satellite links) increases significantly
Solution Approach 1:
The switching function is segmented between the MSC and the gateway. The gateway performs local switching for calls within the same BSS or adjacent BSSs, while the MSC handles inter-BSS and long-distance calls. This segmentation reduces backhaul traffic by keeping local calls local.
Solution Approach 2:
The gateway pre-processes and switches calls locally before they reach the MSC. By performing preliminary switching operations at the gateway for eligible local calls, the system avoids unnecessary backhaul transmission, reducing data volume over expensive links while maintaining centralized control for non-local calls.
3Loss of energy
If local switching is implemented within each BSS using conventional methods, then backhaul data transmission is reduced, but the MSC must be modified to include functionality that selects the appropriate local media gateway for each call
Solution Approach 1:
The gateway acts as an intermediary that autonomously determines whether to perform local switching or forward calls to the MSC. It includes intelligence to select appropriate local media gateways and make switching decisions without requiring MSC modification, simplifying the MSC while enabling local switching.
Solution Approach 2:
The gateway performs self-service by autonomously making local switching decisions based on call parameters and network conditions. It independently selects appropriate media gateways and executes local switching without requiring MSC intervention or modification, reducing backhaul traffic while maintaining simple MSC configuration.
Data Source
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AI summary
In one embodiment, a wireless system comprises a host MSC/VLR of a public land mobile network (PLMN) and a plurality of base station subsystems (BSSs). Each BSS includes a respective base station controller (BSC) and one or more base transceiver stations (BTSs). The wireless system further comprises a virtual base station controller (VBSC) communicatively coupled to the plurality of BSSs and the host MSC/VLR. The VBSC appears, from the perspective of the host MSC/VLR, to be a base station controller for the BTSs in the plurality of BSSs. The VBSC and at least some of the BSSs include functionality for locally switching calls in the BSSs.