OFDM Reception Window Timing for Phase-Rotation-Free Demodulation
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Solution Overview
Problem
The increased accuracy requirements for phase errors in OFDM communication systems, particularly in 5G systems, lead to phase rotation issues that degrade communication quality without additional phase correction functions.
Innovation Solution
A communication system that adjusts the demodulation reception window to match phase rotations across frequencies by controlling the rotation amount using RRC messages or control signals, and sets the window head based on CP length and multipath considerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a user equipment connects to multiple cell groups for communication, then communication reliability is improved, but uplink synchronization maintenance becomes complex and power consumption increases
Solution Approach 1:
The patent extracts the uplink synchronization maintenance function from the user equipment and centralizes it in the network device. The network device independently determines uplink timing adjustment parameters and sends them to the user equipment, eliminating the need for the user equipment to perform complex synchronization calculations across multiple cell groups.
Solution Approach 2:
The network device acts as an intermediary that manages uplink synchronization for multiple cell groups. It receives uplink data from user equipment through different cell groups, determines the appropriate timing adjustment parameters, and controls the reception timing, thereby simplifying the user equipment's operation.
2Productivity
If a user equipment transmits uplink data through multiple cell groups simultaneously, then communication efficiency is improved, but determining accurate reception timing becomes difficult
Solution Approach 1:
The network device provides feedback in the form of timing adjustment parameters (K1, K2 values) to the user equipment. These parameters indicate the timing relationship between uplink data transmission and downlink acknowledgment, enabling the user equipment to accurately determine when the network device will receive the data despite transmissions through multiple cell groups with different latencies.
Solution Approach 2:
The network device pre-determines and communicates the timing adjustment parameters to the user equipment before the actual data transmission. This allows the user equipment to proactively adjust its transmission timing to ensure accurate reception at the network device across multiple cell groups.
3Ease of operation
If uplink data transmission timing is not adjusted across different cell groups, then transmission simplicity is maintained, but data arrives at different times causing processing delays
Solution Approach 1:
The patent introduces dynamic timing adjustment parameters that adapt to the specific characteristics of different cell groups. The network device determines appropriate K1 and K2 values based on the latency characteristics of each cell group, allowing flexible timing control that optimizes data arrival synchronization without requiring complex user equipment-side coordination.
Data Source
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AI summary
Provided is a technology capable of securing communication quality without providing an additional function such as phase correction. A base station device and a communication terminal device when operating as a transmitting device rotate inverse fast fourier transform (IFFT) output, and copy a last portion of the rotated IFFT output to a head of the rotated IFFT output as a cyclic prefix (CP) to thereby generate a transmission signal so that there is no phase rotation at a head of a demodulation reception window set in a receiving device.