Broadcast Control Channel Multiplexing for Shared Spectrum Access
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently accessing and managing shared spectrum carriers, particularly in unlicensed bands, due to unpredictable usage by other networks and devices, leading to restricted resource scheduling and increased interference.
Innovation Solution
The implementation of a broadcast, common control channel that is multiplexed with a unicast control channel over a shared spectrum carrier, utilizing semi-static resource allocation based on parameters like cell ID, system bandwidth, and subframe number, along with various modulation and coding schemes such as sequence-based mapping, coherent modulation, and differential modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a broadcast control channel is implemented for shared spectrum access, then access control efficiency is improved, but system complexity increases due to multiplexing with unicast control channel
Solution Approach 1:
The patent combines broadcast control channel and unicast control channel into a single multiplexed transmission structure. The broadcast control channel carries common control information for shared spectrum access while the unicast control channel carries device-specific information, both transmitted over the same physical medium using resource allocation mechanisms that divide time-frequency resources between the two channel types.
Solution Approach 2:
The control channel structure is designed to serve multiple functions simultaneously: it provides both broadcast functionality for common control information dissemination and unicast functionality for device-specific control information, thereby improving access control efficiency without requiring completely separate transmission paths.
2Device complexity
If semi-static resource allocation is used for broadcast control channel, then resource scheduling flexibility is reduced, but implementation complexity decreases
Solution Approach 1:
The patent employs semi-static resource allocation where resource blocks for broadcast control channel are predetermined based on system bandwidth and other parameters. This preliminary configuration simplifies the scheduling process by establishing resource allocation patterns in advance, reducing the computational complexity required for real-time resource management while maintaining adequate adaptability through periodic updates.
3Reliability
If coherent modulation is used for broadcast control channel, then transmission reliability is improved, but reference signal overhead increases
Solution Approach 1:
The patent utilizes coherent modulation schemes for the broadcast control channel, which require reference signals for accurate demodulation. By carefully managing the reference signal density and positioning within the allocated resource blocks, the system achieves reliable coherent demodulation while controlling the overhead proportion relative to the total resource allocation for the control channel.
Data Source
AI summary
Aspects of the disclosure relate to wireless communication over a shared spectrum carrier utilizing a broadcast, common control channel. The broadcast control channel may be multiplexed with a unicast control channel. Further, a scheduling entity may allocate a semi-static set of resources for the broadcast control channel, providing a shared search space on the shared spectrum carrier. The resource allocation for the shared search space may be based on one or more parameters, which may be cell-specific parameters. This shared search space may include resources distributed across the shared spectrum carrier, or a contiguous set of resources that spans only a portion of the carrier. The broadcast control channel may be configured for high reliability, and may carry time-critical control information relating to access control for the shared spectrum carrier. Other aspects, embodiments, and features are also claimed and described.