Reference Signal Sequence Selection via Cyclic Shift
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Solution Overview
Problem
In wireless communications, existing reference signal sequences can cause significant degradation in time domain frequency offset estimations and cross-interference between user equipment (UEs), particularly in high Doppler scenarios and shared channel transmissions.
Innovation Solution
The implementation of a method to identify a reference signal sequence from a set of predefined sequences, where each wireless device selects a sequence based on a cyclic redundancy check (CRC) and cyclic shift associated with the control channel, reducing the likelihood of using sequences that cause degradation and minimizing cross-interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing reference signal sequences are used, then channel estimation can be performed, but significant degradation occurs in time domain frequency offset estimations and cross-interference between UEs increases
Solution Approach 1:
The patent applies parameter changes by modifying the reference signal sequence selection based on cyclic shift values. Instead of using fixed reference signal sequences, the system dynamically selects sequences from a set of predefined sequences using different cyclic shifts (e.g., 0, 3, 6, 9) as parameters. This parameter variation reduces cross-interference between UEs and improves time domain frequency offset estimation accuracy by avoiding sequences that cause degradation in high Doppler scenarios.
2Ease of manufacture
If a fixed reference signal sequence is used, then implementation is simple, but degradation in time domain frequency offset estimations occurs in high Doppler scenarios
Solution Approach 1:
The patent implements dynamics by transitioning from static fixed reference signal sequences to dynamic sequence selection based on cyclic shift parameters. The system dynamically chooses reference signal sequences from a predefined set using cyclic shifts derived from control channel assignments. This dynamic approach maintains implementation simplicity through predefined sequences while significantly improving frequency offset estimation accuracy in high Doppler scenarios by adapting sequence selection to specific transmission conditions.
3Ease of operation
If reference signal sequences are selected without considering cyclic shift, then sequence selection is straightforward, but cross-interference between UEs using shared channels increases
Solution Approach 1:
The patent applies local quality by assigning different cyclic shift parameters to different UEs based on their specific control channel assignments and resource allocations. Each UE uses a locally optimized reference signal sequence selected according to its unique cyclic shift value, which is determined by factors such as resource block assignment and UE identification. This localized parameter customization reduces cross-interference between UEs while maintaining straightforward sequence selection through predefined patterns.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A first wireless device may identify a reference signal sequence (e.g., a demodulation reference signal (DMRS) sequence) based on a cyclic shift associated with a control channel for communications with a second wireless device. For example, the first wireless device may identify the cyclic shift associated with transmitting a message to the second wireless device via the control channel. In another example, the first wireless device may estimate the cyclic shift associated with receiving a message from the second wireless device via the control channel. The first wireless device may then communicate with the second wireless device based on the reference signal sequence. For example, the first wireless device may transmit or receive (e.g., via a shared channel) the reference signal sequence to or from the second wireless device.