Hierarchical RAN and Gateway Caching for Wireless Backhaul Reduction
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Solution Overview
Problem
Conventional network-level caching in wireless communication networks leads to back-haul link congestion, degrading the quality of experience for users due to bandwidth constraints, especially for high-bandwidth services like HD movie streaming, and exacerbates issues during 'flash crowd' events where many users request content simultaneously.
Innovation Solution
Implementing content caching at the edge of the wireless communication network by operating RAN caches within the RAN portion of the network under the control of a gateway cache at the packet data network interface level, allowing for proxied content requests and serving content from the RAN cache based on control signaling, thereby reducing the need for back-hauling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If content caching is implemented at the network level (GGSN), then content delivery is improved, but back-haul link congestion occurs due to bandwidth constraints
Solution Approach 1:
The patent divides the network caching system into two segments: a network-level cache at the GGSN and a RAN-level cache at the radio access network. This segmentation allows content to be cached at multiple levels, reducing the burden on back-haul links by serving content from the RAN cache when available, while maintaining network-level caching for broader content availability.
Solution Approach 2:
The patent introduces a new spatial dimension for caching by placing a cache at the RAN level, which is geographically closer to end users than the traditional network-level cache. This dimensional addition creates a hierarchical caching structure that reduces back-haul traffic by serving content locally at the RAN edge.
2Reliability
If content is cached at the network level, then content availability is improved, but latency increases due to back-haul transport requirements
Solution Approach 1:
The patent implements preliminary caching of content at the RAN level, anticipating user requests by pre-positioning content closer to the edge of the network. This preliminary action at the RAN cache eliminates the need for real-time back-haul transport when content is requested, significantly reducing latency while maintaining content availability.
Solution Approach 2:
The RAN cache acts as an intermediary between the network-level cache and end users. It receives content from the network-level cache and serves it locally to users, mediating the content delivery process to reduce latency by eliminating direct back-haul transport for cached content.
3Quantity of substance
If RAN cache is introduced, then back-haul loading is reduced, but device complexity increases due to additional cache management
Solution Approach 1:
The patent merges the functionality of the network-level cache and RAN cache into a coordinated hierarchical system. The GGSN and RAN cache work together with defined roles: the GGSN manages network-level caching and content distribution, while the RAN cache handles local content serving. This merging reduces back-haul traffic by utilizing the RAN cache for local content, while maintaining manageable complexity through clear functional division.
4Loss of information
If network-level caching is used, then billing visibility is maintained, but user experience deteriorates during flash crowd events
Solution Approach 1:
The patent segments the caching function between network-level and RAN-level caches, allowing the RAN cache to handle local flash crowd events independently. This segmentation enables the RAN cache to serve local users during flash crowds without affecting network-level billing visibility, as the GGSN retains control over content distribution and can monitor usage for billing purposes.
Solution Approach 2:
The RAN cache serves as an intermediary that handles local content requests during flash crowd events, preventing back-haul congestion and maintaining user experience. Simultaneously, the network-level cache and GGSN maintain billing visibility by tracking content distribution and usage patterns, ensuring both user experience and billing requirements are met.
Data Source
AI summary
The teachings herein describe methods and apparatuses for caching content at the “edge” of a wireless communication network, based on operating one or more RAN caches within the RAN portion of the network under the control of a gateway cache that operates at the packet data network interface level within the CN portion of the network. Each RAN cache operates as subordinate of the gateway cache, based on intercepting content requests from wireless devices operating within the RAN, providing corresponding proxied content requests to the gateway cache, and serving or not serving requested content from the RAN cache in dependence on control signaling from the gateway cache. Such operation permits all decision making to reside in the gateway cache, thereby retaining full visibility for critical billing and lawful intercept functions, while obviating in many instances the need to back haul such content.