UE Power Allocation for D2D and Cellular in LTE
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Solution Overview
Problem
In LTE systems with D2D sub-frames, UEs face challenges in managing transmission power when simultaneously handling cellular network communication channels and D2D signals across different serving cells, particularly in overlapping areas, where the total power required exceeds the maximum configured power, and prioritization of services is needed.
Innovation Solution
A power control method that calculates and allocates transmission power to each serving cell based on the total required power and maximum configured power, prioritizing important services by determining which channels or signals can be transmitted simultaneously and adjusting power levels accordingly, using tables to determine compatibility and allocation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a UE transmits cellular network communication channels/signals and D2D signals/channels simultaneously in different serving cells within the same uplink sub-frame or in overlapping areas, then the service coverage and communication capability are improved, but the total transmission power required exceeds the maximum transmission power configured in the UE
Solution Approach 1:
The patent segments the transmission power allocation by dividing serving cells into first serving cells (for cellular network communication) and second serving cells (for D2D communication). This segmentation allows independent power control for each type of communication, enabling the UE to manage total power consumption while maintaining service coverage across multiple cells.
Solution Approach 2:
The patent applies local quality by configuring different power control parameters specifically for second serving cells engaged in D2D communication. The network device can independently adjust power control parameters (such as target received power, path loss compensation factors) for D2D channels/signals in second serving cells, allowing optimized power distribution that ensures D2D communication quality while controlling overall power consumption within the UE's maximum power limit.
2Adaptability or versatility
If a UE allocates transmission power to multiple channels/signals simultaneously, then the communication functionality is improved, but the difficulty of power allocation management increases
Solution Approach 1:
The patent simplifies power allocation management by segmenting serving cells into distinct categories (first serving cells for cellular communication, second serving cells for D2D communication). This segmentation creates separate power control domains, allowing the UE to manage power allocation independently for each category rather than handling all channels/signals uniformly, thereby reducing the complexity of power allocation management.
Solution Approach 2:
The network device performs preliminary action by pre-configuring power control parameters for second serving cells before the UE engages in D2D communication. This advance configuration includes setting target received powers, path loss compensation factors, and other power control parameters, which simplifies the UE's real-time power allocation decisions and reduces the complexity of dynamic power management during simultaneous cellular and D2D operations.
Data Source
AI summary
The present disclosure provides a power control method applicable to a system configured with serving cells having D2D sub-frames. The method includes: a user equipment (UE) calculates transmission power required by each of serving cells configured for the UE; the UE determines a signal or channel that is possible to be transmitted in each of the serving cells and allocates transmission power to the signal or channel according to conditions of the serving cells configured for the UE and a relation between the amount of total transmission power required by all of the serving cells configured for the UE and the amount of maximum transmission power configured in the UE; the UE transmits the signal or channel of a serving cell configured for the UE according to the transmission power allocated to the signals or channels. The present disclosure also provides an user equipment. According to the present disclosure, important signals or channels can have priority in power allocation. As such, performances of important signals and channels are firstly ensured.