Control Channel Slot Structure for Shared Spectrum Communication
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Solution Overview
Problem
Current cellular systems, such as LTE and LTE-A, face challenges in utilizing Industrial, Scientific, and Medical (ISM) bands due to the need for continuous and synchronous resource allocation for control channels, which is problematic with shared spectrum resources like those used in WLAN and Bluetooth communication, leading to inefficient use of frequency resources.
Innovation Solution
Implementing a communication system that controls transceivers to use shared data channels with a sensing period and data period, and common and dedicated control channels on shared spectrum with control channel slots, where the uplink part occurs at the same time as the sensing period of a data channel slot, utilizing frequency hopping to manage resource allocation and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous and synchronous resource allocation is used for control channels in LTE/LTE-A systems, then control channel reliability is improved, but interference with other shared spectrum users increases and spectrum efficiency deteriorates
Solution Approach 1:
The patent implements periodic sensing periods interspersed with data periods instead of continuous control channel transmission. The sensing period occurs at regular intervals (e.g., every other slot) where devices perform LBT, followed by data periods for actual transmission. This periodic structure maintains control channel functionality while reducing continuous interference with other shared spectrum users like WLAN systems.
Solution Approach 2:
The patent introduces dynamic resource allocation where control channel resources are not fixed but adaptively assigned based on sensing results and traffic conditions. The network can dynamically adjust which slots are allocated for control channels versus data transmission, allowing the system to respond to changing spectrum conditions and minimize interference with other users of the shared spectrum.
2Productivity
If more frequency resources are allocated to support increased data traffic, then data traffic capacity is improved, but spectrum efficiency deteriorates due to limited available frequency resources
Solution Approach 1:
The patent segments the spectrum resources both in frequency and time domains. Instead of allocating contiguous frequency blocks, the system divides resources into multiple smaller slots that can be independently allocated. This segmentation allows more flexible and efficient utilization of limited spectrum resources, supporting increased data traffic capacity without requiring additional frequency bandwidth.
Solution Approach 2:
The patent transitions from primarily frequency-domain resource allocation to time-domain resource allocation. By introducing the time dimension with slot-based allocation, sensing periods, and data periods, the system can support increased traffic capacity through temporal multiplexing rather than requiring additional frequency resources, thereby improving spectrum efficiency.
3Productivity
If license-exempt bands are used for offloading traffic, then core network congestion is reduced, but control channel transmission becomes challenging due to shared spectrum characteristics
Solution Approach 1:
The patent implements preliminary sensing actions before data transmission. Devices perform listen-before-talk (LBT) during sensing periods to check if the channel is clear before attempting control channel or data transmission. This preliminary action prevents collisions and ensures reliable control channel operation in the shared license-exempt spectrum, enabling effective traffic offloading despite the challenging environment.
Solution Approach 2:
The patent creates a universal resource allocation framework that handles both control channels and data channels using the same slot-based structure and sensing mechanism. This multi-functional approach simplifies the overall system complexity by providing a unified method for resource management in license-exempt bands, rather than requiring separate complex mechanisms for control and data channels.
Data Source
AI summary
Apparatus and method for communication are provided. The solution includes controlling the communication of a transceiver on shared data channels using a data channel slot including a sensing period and a data period and controlling a transceiver to communicate on common and dedicated control channels on a shared spectrum using control channel slots, each control channel slot including a downlink part and an uplink part, wherein the uplink part occurs at the same time as the sensing period of a data channel slot.