Coded Caching Scheduler for Wireless Video Streaming
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Solution Overview
Problem
Current wireless communication networks face challenges in meeting increasing video traffic demand due to limited resource blocks and fading environments, where per-user throughput decreases as the number of users increases, and existing solutions like opportunistic scheduling and coded caching do not effectively exploit receiver device memory and channel variations.
Innovation Solution
A network entity that distributes files to multiple receiver devices by segmenting files, using caches on receiver devices to decode encoded file segments, and employing a scheduler to dynamically assign transmission queues based on channel quality and priority, combining files into codewords for multicast transmissions to optimize throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coded caching is applied to fading environments, then receiver devices can store and decode file segments, but transmissions must be at the bitrate supported by the worst channel quality, bringing down total system performance
Solution Approach 1:
The patent implements dynamic queue assignment where transmission queues are reassigned to different receiver devices based on varying channel conditions. The scheduler monitors channel quality and dynamically adjusts which receiver devices receive which encoded file segments, allowing the system to adapt to fading environments and exploit temporal channel variations rather than being constrained by worst-case channel conditions.
Solution Approach 2:
The system changes the parameter of transmission bitrate by allowing different queues to be transmitted at different bitrates appropriate for each receiver device's current channel quality. Instead of using a single conservative bitrate for all transmissions, the patent enables parameter adaptation where each queue can be transmitted at an optimal bitrate based on the assigned receiver device's channel conditions.
2Productivity
If opportunistic scheduling is used to handle increased data demand, then radio resource efficiency improves, but per-user throughput scales badly with the number of users at best as loglog(K)/K
Solution Approach 1:
The patent segments files into multiple encoded file segments and distributes them across multiple transmission queues. Each receiver device receives a specific subset of these segments based on its cache contents and channel conditions. This segmentation allows the system to serve multiple users simultaneously with different queue assignments, improving both resource efficiency and maintaining per-user throughput as the number of users increases.
Solution Approach 2:
The patent creates a multi-functional system where transmission queues serve multiple purposes: some queues are dedicated to specific receiver devices while others can be dynamically assigned to different devices based on channel conditions. This universal queue structure allows the system to efficiently handle varying user demands and channel conditions, maintaining good per-user throughput scaling.
3Quantity of substance
If the number of transmission queues increases to support more receiver devices, then system capacity increases, but device complexity and scheduling overhead increase
Solution Approach 1:
The patent implements a dynamic queue assignment mechanism where the scheduler adapts queue assignments to current channel conditions and user demands. This dynamic approach allows the system to efficiently manage a moderate number of queues by reusing them across different receiver devices at different times, achieving high system capacity without requiring an excessive number of permanent queues and associated complexity.
Data Source
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AI summary
The invention relates to a network entity (101) configured to distribute a plurality of files to a plurality of receiver devices (103a-c), including a first receiver device (103a) and a second receiver device (103b), wherein each of the plurality of files can be segmented into a plurality of file segments and each of the plurality of receiver devices (103a-c) comprises a cache (107a) for caching one or more of the plurality of file segments. The network entity (101) comprises: a processing unit (101a) configured to encode for one or more of the plurality of files one or more file segments of the plurality of file segments of the respective file; and a scheduler (101b) configured to schedule the transmission of the plurality of file segments to the plurality of receiver devices (103a-c) using a plurality of queues of file segments, including a first queue and a second queue, wherein the number of the plurality of queues is larger than or equal to the number of the plurality of receiver devices (103a-c) and smaller than twice the number of the plurality of receiver devices (103a-c), and wherein the scheduler (101b) is further configured to assign the plurality of queues to the plurality of receiver devices (103a-c) such that the first queue comprises file segments for the first receiver device (103a) and the second queue comprises file segments for the second receiver device (103b) and encoded file segments decodable by the first receiver device (103a) and the second receiver device (103b). Moreover, the invention relates to a corresponding method for distributing a plurality of files to a plurality of receiver devices (103a-c).