Base Station Cyclic Shift Adjustment for Frequency Deviation
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Solution Overview
Problem
The frequency deviation between the center frequency for receiving a signal by UE and the center frequency for transmitting a signal by a base station, which is greater than the subcarrier spacing, reduces the quantity of UEs that can perform orthogonal code division multiplexing through cyclic shifts, leading to reduced uplink resource utilization.
Innovation Solution
A method where the base station determines a target root indicator from a sequence indicator set to generate a signal sequence, ensuring that cyclic shifts resulting from frequency deviation and delay spread fall within allocated intervals, allowing for increased orthogonal code division multiplexing without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the frequency deviation between base station transmission center frequency and UE reception center frequency is greater than subcarrier spacing, then the cyclic shift values must be reserved to avoid interference, but the quantity of UEs that can perform orthogonal code division multiplexing is reduced
Solution Approach 1:
The patent changes the parameter of cyclic shift value calculation by introducing a frequency deviation compensation term. Instead of using fixed cyclic shift values, the system dynamically adjusts cyclic shift values based on the detected frequency deviation between base station and UE center frequencies. This compensation mechanism allows the system to maintain orthogonal code division multiplexing for more UEs even when frequency deviation exceeds subcarrier spacing, thereby resolving the contradiction between reliability and quantity.
2Reliability
If more cyclic shift values are reserved to accommodate frequency deviation, then interference between UEs is avoided, but uplink resource utilization is reduced
Solution Approach 1:
The patent dynamically adjusts the cyclic shift value parameter based on the actual frequency deviation detected in the uplink signal. By compensating for frequency deviation in real-time, the system can reuse cyclic shift values that would otherwise be reserved, thereby increasing uplink resource utilization while maintaining interference avoidance through accurate frequency alignment.
3Ease of manufacture
If cyclic shift values are allocated without frequency deviation compensation, then resource allocation is simple, but cyclic shifts from frequency deviation and delay spread overlap causing interference
Solution Approach 1:
The patent implements a feedback mechanism where the base station detects the frequency deviation in the uplink signal from each UE and uses this feedback information to adjust the cyclic shift value allocation. The base station calculates the frequency deviation by comparing the received signal frequency with the expected frequency, then compensates the cyclic shift values accordingly. This feedback-based compensation ensures that cyclic shifts from frequency deviation and delay spread do not overlap, maintaining interference freedom while keeping resource allocation manageable through automated detection and adjustment.
Data Source
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AI summary
Embodiments of the present invention disclose a signal receiving method, a signal transmission method, and a device, and relate to the communications field, so as to resolve a problem that a supported quantity of UEs that perform orthogonal code division multiplexing through cyclic shifts is relatively small when a frequency deviation between a center frequency for receiving a signal by UE and a center frequency for transmitting a signal by a base station is greater than a subcarrier spacing used for communication between the base station and the UE. A specific solution is as follows: determining, by a base station, a target root indicator from a sequence indicator set, where the sequence indicator set is {A1, B1, A2, B2,···, As, Bs}, Ai = i(mod K) Bi = -i(mod K), Ai and Bi are root indicators of ZC sequences, i is an integer greater than or equal to 1 and less than or equal to s, s is an integer greater than or equal to 1 and less than or equal to └K/2┘-1, └ ┘ indicates rounding down, and K is a length of a ZC sequence; generating, by the base station, a signal sequence based on the target root indicator; receiving, by the base station, an uplink signal; and processing, by the base station, the uplink signal based on the signal sequence. The embodiments of the present invention are used in a signal transmission process.