Base Station Superposition Transmission Power Offset
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Solution Overview
Problem
In mobile communication systems, superposition transmission of unicast (PDSCH) and MBMS using the same time-frequency resource leads to reduced transmission power for PDSCH, resulting in deteriorated demodulation performance due to low demodulation reference signal power, affecting channel estimation accuracy.
Innovation Solution
A base station and radio terminal configuration that performs superposition transmission by setting the demodulation reference signal power higher than PDSCH data power and using an MBSFN reference signal for demodulating MBMS data, while excluding overlapping time-frequency resources from the boost process, to enhance channel estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If superposition transmission of MBMS and PDSCH using the same time-frequency resource is implemented, then resource utilization efficiency is improved, but transmission power for PDSCH is reduced leading to deteriorated demodulation performance
Solution Approach 1:
The patent changes the power allocation parameters by introducing a power offset parameter that allows the demodulation reference signal to have higher power than the PDSCH data. This parameter adjustment resolves the contradiction by ensuring sufficient reference signal power for accurate channel estimation while maintaining the superposition transmission structure that improves resource utilization.
Solution Approach 2:
The patent applies local quality by differentiating power allocation between different signal components within the superposition transmission. Specifically, the demodulation reference signal is allocated higher power locally compared to the PDSCH data, ensuring that the critical channel estimation function is maintained while overall resource efficiency is improved through superposition.
2Measurement precision
If demodulation reference signal power is increased to maintain channel estimation accuracy, then demodulation performance is improved, but available transmission power for PDSCH data is reduced
Solution Approach 1:
The patent introduces a power offset parameter that explicitly controls the power relationship between the demodulation reference signal and PDSCH data. By setting this parameter appropriately, the system ensures sufficient reference signal power for accurate channel estimation while maintaining adequate power for data transmission, resolving the contradiction between measurement precision and available power.
3Adaptability or versatility
If MBMS transmission is introduced using superposition transmission, then service diversity is improved, but unicast transmission capacity may be affected
Solution Approach 1:
The patent uses power offset parameters to dynamically adjust the power distribution between MBMS and unicast PDSCH transmissions. This allows the system to maintain sufficient unicast transmission capacity while introducing MBMS service diversity, as the parameters can be tuned to ensure both services receive adequate power resources.
Data Source
AI summary
A base station according to one embodiment performs superposition transmission that is a scheme for performing MBMS transmission and PDSCH transmission by using the same time-frequency resource. The base station performs the processes of; transmitting PDSCH data to a radio terminal by the PDSCH transmission and transmitting a demodulation reference signal for demodulating the PDSCH data; and transmitting, to the radio terminal, information indicating a ratio or an offset of a transmission power of the demodulation reference signal with respect to a transmission power of the PDSCH data.