Direct Communication Power Control via Bounded Transmission Slots
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Solution Overview
Problem
Direct communication systems face inefficiencies due to the lack of centralized power control, leading to collisions and reduced spectrum efficiency, especially in random access phases, as all devices transmit at maximum power, resulting in failed transmissions and inadequate frequency reuse.
Innovation Solution
Implementing a direct communication method with contention slots and transmission slots having different transmission power upper bounds, allowing devices to adjust their power levels within these bounds to reduce interference and enhance spectrum efficiency, using a TDM-based Interference Control mechanism to manage power and priority levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all communication devices transmit at the largest power in the random access phase, then the chance of successful transmission is improved, but transmission collisions increase and spectrum efficiency deteriorates
Solution Approach 1:
The patent changes the transmission power parameter from a fixed maximum value to a dynamically controlled value with an upper bound. The coordinator device sets a transmission power upper bound for contention slots, and communication devices adjust their transmission power to be less than or equal to this bound, transforming the power transmission mode from uncontrolled maximum power to controlled bounded power, thereby resolving the contradiction between successful transmission rate and spectrum efficiency
Solution Approach 2:
The coordinator device acts as an intermediary between communication devices during the random access phase. It broadcasts the transmission power upper bound for contention slots, mediating the power control between multiple devices. This intermediary control mechanism prevents the 'listen-before-talk' collision problem by ensuring all devices transmit within acceptable power bounds, thus improving both successful transmission rates and spectrum efficiency
2Length of stationary object
If transmission power is increased to extend transmission range, then the coverage area is improved, but interference to other devices increases and frequency reuse decreases
Solution Approach 1:
The patent controls the transmission power parameter within a bounded range rather than using maximum power. By setting an upper bound on transmission power for contention slots, the system ensures that transmission range is sufficient for successful communication while limiting the harmful interference generated to other devices, thus resolving the contradiction between transmission range and interference levels
Solution Approach 2:
The patent applies different transmission power upper bounds to different contention slots, creating local quality variations in power transmission. The coordinator device can assign appropriate power bounds to different slots based on local interference conditions and device distributions, allowing optimal transmission range in each local context while minimizing overall interference
Data Source
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AI summary
A direct communication method, a direct communication device, and a coordinator device using the same method are provided. The direct communication method may be adapted for direct communications between devices with multiple priorities/power upper bounds/ranges. Multiple contention/transmission slots with different power upper bounds or priorities are used as a configuration to allocate resource for the direct communication. The associated configuration acquisition is also disclosed. The direct communication method may also adopt relative periodicity of occurrence of the contention/transmission slots, and may adaptively vary the relative periodicity. The direct communication method may include an associated monitor scheme for spectrum regulation.