Base Station Phase Rotation for Multicarrier Symbol Coherence
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Solution Overview
Problem
In multicarrier communication systems, the repetition technique leads to cancellation between same symbols transmitted from adjacent base stations, resulting in reduced received power and degraded performance due to phase variations in channels.
Innovation Solution
The base station applies phase rotations to repeated symbols such that the phase rotation differences between symbols in adjacent cells or sectors are distinct, ensuring that symbols remain in phase at the mobile station, thereby preventing cancellation and maintaining diversity gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the repetition technique is used to transmit the same symbols from multiple base stations, then diversity gain can be obtained, but phase variations in the channel cause cancellation between symbols resulting in reduced received power
Solution Approach 1:
The patent applies phase rotation to the repeated symbols before transmission. By changing the phase parameter of the symbols transmitted from different base stations, the invention ensures that symbols arrive at the mobile station with consistent phases, preventing cancellation and maintaining received power while preserving diversity gain
Solution Approach 2:
The patent preemptively applies phase rotation to counteract the phase variations that occur during transmission through the channel. By pre-adjusting the phase of transmitted symbols, the invention prevents the harmful cancellation effect before it occurs at the receiving end
Data Source
AI summary
A base station is provided to suppress a drop of receiving power and deterioration of receiving characteristics by cancellation between the same symbols in the case of application of a repetition technology to multiple-carrier communication. In this base station (100), a repetition unit (103) for reproducing (making repetition of) each data symbol input from a modulating unit (102) to make out a plurality of identical data symbols, and a phase rotating unit (106) for giving a phase rotation to a data symbol input from a multiplexing unit (105). This time the phase rotating unit (106) provides the identical symbols made out by the repetition with the phase rotation which has a phase rotating difference different from phase rotating differences among a plurality of identical symbols transmitted with the ones identical to a plurality of the identical symbols at time and a frequency identical to those of a plurality of the identical symbols in adjacent cells or adjacent sectors.