SRS Sequence Mapping for Multi-Antenna Channel Estimation
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Solution Overview
Problem
In mobile wireless communication systems, particularly in LTE, UE with multiple antennas face challenges in simultaneously transmitting SRS due to limitations in power amplifier configuration, leading to inefficient channel estimation and data decoding.
Innovation Solution
The method involves configuring cyclic shifts for each antenna, generating unique SRS sequences, and mapping them to resource elements, allowing simultaneous SRS transmission across multiple antennas with potentially different bandwidths, enabling efficient channel estimation and data decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If SRS is transmitted alternately through multiple antennas using time division multiplexing, then device complexity is reduced and power amplifier configuration is simplified, but channel estimation efficiency deteriorates and measurement time increases
Solution Approach 1:
The patent segments the SRS transmission by assigning different cyclic shift values to different antennas. Each antenna transmits an SRS sequence with a unique cyclic shift, allowing the base station to distinguish and estimate channels for each antenna simultaneously. This resolves the contradiction by enabling parallel channel estimation without requiring complex power amplifier configurations for simultaneous transmission.
Solution Approach 2:
The patent changes the cyclic shift parameter of the SRS sequence for each antenna. By configuring different cyclic shift values (e.g., 0, 3, 6, 9 for four antennas), the system enables simultaneous transmission differentiation without hardware complexity. The base station uses these distinct cyclic shifts to separately estimate channels for each antenna, improving channel estimation efficiency while maintaining simple power amplifier configuration.
2Loss of information
If SRS is transmitted alternately through multiple antennas, then additional signaling is reduced, but measurement time increases and data decoding reliability deteriorates
Solution Approach 1:
The patent segments the channel estimation process by using cyclic shift differentiation. Each antenna's SRS transmission is uniquely identified by its cyclic shift value, allowing the base station to simultaneously estimate all antenna channels in one measurement period. This eliminates the need for alternating transmissions, reducing measurement time while maintaining low signaling overhead, thereby improving data decoding reliability.
Solution Approach 2:
The patent applies preliminary action by pre-configuring distinct cyclic shift values for each antenna before transmission. This allows the base station to prepare the channel estimation process in advance, simultaneously processing all antenna channels without sequential delays. The reduced measurement time and eliminated signaling overhead directly improve data decoding reliability.
3Measurement precision
If multiple antennas transmit SRS simultaneously with different bandwidths, then channel estimation precision is improved, but device complexity and resource allocation difficulty increase
Solution Approach 1:
The patent applies local quality by allowing different bandwidth configurations for different antennas based on their specific channel conditions and requirements. Each antenna can be configured with an appropriate bandwidth (e.g., antenna 0 with bandwidth B0, antenna 1 with bandwidth B1), optimizing channel estimation precision for each local scenario. The cyclic shift differentiation simplifies resource allocation by providing a clear distinction mechanism, reducing overall device complexity despite the varied bandwidth requirements.
Data Source
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AI summary
Disclosed is a method for transmitting a sounding reference signal from a mobile terminal that includes plural antennas. Different plural sounding reference signal sequences that have mutual orthogonality are mapped to each antenna, and then transmitted. Or, the same sounding reference signal sequence is mapped to the plural antennas after precoding or cyclic delay diversity processing, and then transmitted.