Synchronized Estimation Pilot Transmission for Accurate SINR
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Solution Overview
Problem
In wireless communication networks with smart antenna technology, errors in estimating downlink communication quality lead to inefficiencies in frequency utilization, particularly due to uncertainties in intercell interference and beam pattern synchronization, resulting in reduced throughput at cell edges.
Innovation Solution
The solution involves synchronizing base stations to transmit estimation pilots using the same directional beams as data transmission, ensuring correct SINR estimation by considering intercell interference, and using time or frequency division multiplexing to avoid interference, thus ensuring accurate communication quality feedback for adaptive modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If base stations transmit estimation pilots using different directional beams independently, then each base station can perform beamforming optimization, but intercell interference estimation becomes inaccurate and frequency utilization efficiency decreases
Solution Approach 1:
The patent merges the beam pattern selection of multiple base stations by synchronizing them to use the same directional beam for estimation pilot transmission. This coordination eliminates intercell interference estimation errors that occur when base stations use different beams, thereby improving both measurement precision and frequency utilization efficiency.
Solution Approach 2:
The patent implements a feedback mechanism where mobile stations measure the downlink communication quality based on synchronized estimation pilots and feed back this information to base stations. This feedback enables accurate SINR estimation, which is then used for adaptive modulation and coding decisions, resolving the contradiction between measurement accuracy and system efficiency.
2Adaptability or versatility
If base stations use different directional beams for estimation pilot transmission, then beamforming flexibility is maintained, but SINR estimation errors occur due to beam pattern desynchronization
Solution Approach 1:
The patent applies preliminary action by having base stations pre-synchronize their beam pattern selections before transmitting estimation pilots. This advance coordination ensures that all base stations use the same directional beam for pilot transmission, eliminating SINR estimation errors while maintaining the ability to adapt to different channel conditions through coordinated beam selection.
3Ease of operation
If packet scheduling is performed without synchronized beam patterns, then scheduling flexibility is preserved, but communication quality feedback becomes inaccurate at cell edges
Solution Approach 1:
The patent applies local quality by implementing beam synchronization specifically for estimation pilot transmission while maintaining independent packet scheduling flexibility. This localized coordination ensures accurate communication quality feedback at cell edges where intercell interference is most significant, without constraining the overall packet scheduling operations.
Data Source
AI summary
A wireless communication system comprises radio base station apparatuses each of which transmits an estimation pilot in advance for estimating the quality of a downlink communication after a spatial signal processing performed after a time unified among the radio base station apparatuses; and radio terminal apparatuses each of which receives the estimation pilot to determine the quality of the downlink communication, thereby reporting the determined downlink communication quality to the radio base station apparatus via an uplink channel. The estimation pilot is transmitted at the same time and frequency established among the radio base station apparatuses by use of the same directivity beam as used for transmitting the data after the unified time.