Uplink SRS Transmission Using Frequency Comb and Cyclic Shift
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Solution Overview
Problem
Existing mobile terminals with multiple transmission antennas cannot support concurrent transmission of SRSs over multiple antennas, leading to inaccurate uplink channel status information and channel estimation due to SRSs being transmitted at long intervals, which hampers the base station's ability to perform precise channel estimation.
Innovation Solution
Configuring radio frequency transmission modules of a mobile terminal with different Transmission Comb (TC) values and Cyclic Shift (CS) values allows for concurrent transmission of SRSs over multiple antennas using Frequency Division Multiplexing (FDM) or Code Division Multiplexing (CDM), enabling the base station to receive SRSs in the same transmission cycle without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If SRSs are transmitted alternatively over multiple transmission antennas in different transmission cycles, then the device complexity is reduced and ease of operation is improved, but the measurement precision of uplink channel status information deteriorates due to long transmission intervals
Solution Approach 1:
The patent merges multiple SRS transmissions into the same transmission cycle by allowing concurrent transmission from multiple antennas. Different antennas transmit SRSs simultaneously using frequency division multiplexing (different frequency comb offsets) or code division multiplexing (different cyclic shifts), combining what was previously sequential transmissions into a single time slot.
Solution Approach 2:
The patent introduces frequency and code dimensions to resolve the time conflict. Instead of separating SRS transmissions only in time (different transmission cycles), the invention separates them in frequency (different frequency comb offsets for different antennas) and code (different cyclic shifts for different antennas), enabling simultaneous transmission while maintaining orthogonality.
2Productivity
If SRS transmission interval is increased to allow alternative transmission over multiple antennas, then the productivity of other transmissions is improved, but the measurement precision of channel estimation deteriorates
Solution Approach 1:
Multiple antenna SRS transmissions are merged into the same transmission cycle, maintaining frequent channel estimation updates while still supporting multi-antenna operation. This combines the channel estimation benefits of frequent transmission with the spatial diversity of multiple antennas.
Solution Approach 2:
The invention moves the separation mechanism from the time dimension to the frequency and code dimensions. By using different frequency comb offsets and cyclic shifts for different antennas, the system enables simultaneous multi-antenna SRS transmission without increasing time interval, thus maintaining both productivity and measurement precision.
3Measurement precision
If concurrent SRS transmission over multiple antennas is enabled, then the measurement precision of uplink channel status information is improved, but the device complexity increases due to need for different TC and CS values configuration
Solution Approach 1:
Different transmission parameters (frequency comb offsets and cyclic shifts) are assigned to different antennas based on their specific roles. Each antenna receives a locally optimized configuration that enables orthogonal transmission, with the base station managing the parameter distribution according to antenna identity and transmission requirements.
Solution Approach 2:
The invention changes the transmission parameters (frequency comb offset and cyclic shift) for different antennas to create orthogonal signals. By systematically varying these parameters across antennas, the system enables concurrent transmission while maintaining signal distinguishability, with the base station coordinating the parameter assignment.
Data Source
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AI summary
The field of wireless communications is related, especially the technique of transmitting uplink sounding reference signal (SRS) by a mobile terminal with multiple transmission antennas is related. A method for receiving uplink sounding reference signal includes the following steps: receiving the SRS signals, which are respectively transmitted from respective radio frequency transmission modules of the mobile terminal according to the respectively allocated Transmission Comb (TC) values and Cyclic Shift (CS) values when the transmission period arrives, wherein TC values and/or CS values allocated for any two radio frequency transmission modules are different; determining the radio frequency transmission module corresponding to every received SRS signal according to the TC values and CS values respectively allocated for respective radio frequency transmission modules. A device for receiving uplink sounding reference signal, a method and a device for transmitting uplink sounding reference signal are also provided. Because different TC values and/or different CS values are allocated for respective radio frequency transmission modules, (multiple) radio frequency transmission modules can transmit SRS signals through (multiple) transmission antennas during the same transmission period by way of Frequency Division Multiplex (FDM) or Code Division Multiplex (CDM).