Uplink SRS TD-OCC Coding for Higher Capacity and Phase Coherency
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Solution Overview
Problem
The limited capacity of SRS resources in current wireless communication systems restricts the number of UEs that can transmit simultaneously, and frequency hopping, while enhancing capacity, introduces phase coherency issues and sensitivity to interference.
Innovation Solution
Implementing Time Domain Orthogonal Cover Codes (TD-OCC) over multiple SRS repetitions, allowing UEs to indicate support for TD-OCC configurations, including repetition factors and codes, to enhance SRS capacity and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency hopping is used to enhance SRS capacity, then the number of UEs that can transmit simultaneously increases, but phase coherency between different frequency hops deteriorates and sensitivity towards interference increases
Solution Approach 1:
The patent transitions from frequency domain multiplexing (frequency hopping) to time domain multiplexing using orthogonal cover codes. By applying TD-OCC in the time domain across multiple SRS repetitions, the system achieves multi-UE multiplexing without frequency hopping, thereby maintaining phase coherency while increasing SRS capacity.
Solution Approach 2:
The patent introduces Time Domain Orthogonal Cover Codes (TD-OCC) as an intermediary mechanism to enable multiple UEs to transmit SRS simultaneously. The TD-OCC acts as a separating code that allows the base station to distinguish between different UEs' signals in the time domain, eliminating the need for frequency hopping and its associated phase coherency issues.
2Productivity
If frequency hopping is used to enhance SRS capacity, then the number of UEs that can transmit simultaneously increases, but sensitivity towards inter-cell interference increases
Solution Approach 1:
The patent moves the multiplexing mechanism from the frequency domain to the time domain using TD-OCC. This dimensional change allows multiple UEs to be multiplexed without shortening the SRS sequence length in each hop, thereby reducing sensitivity to inter-cell interference while maintaining enhanced capacity.
3Productivity
If TD-OCC is applied over multiple SRS repetitions, then SRS capacity increases and multiple UEs can transmit simultaneously, but device complexity increases due to configuration requirements
Solution Approach 1:
The patent configures TD-OCC by modifying parameters such as the repetition factor and the orthogonal cover code sequence. By changing these parameters, the system enables multiple UEs to transmit simultaneously while managing complexity through standardized configuration options rather than requiring complex custom setups.
Data Source
AI summary
Sounding Reference Signal (SRS) capacity is increased by introducing Time Domain Orthogonal Cover Codes (TD-OCC) over multiple SRS repetitions. A UE may indicate to the network a capability to support TD-OCC for SRS. In response, the network provides configurations controlling the content and format of the SRS. An SRS resource configuration may include at least an SRS Repetition Factor≥2. A TD-OCC configuration may include at least one of a TD-OCC length and a TD-OCC code. The UE C indication may indicate a maximum TD-OCC length that is supported for an SRS resource; all TD-OCC lengths that are supported; that supported TD-OCC lengths are 2n for positive integers n; that different TD-OCC codes are supported for different SRS ports of an SRS resource; or that the TD-OCC length maybe different than the SRS Repetition Factor. Techniques are disclosed herein for implementing all of these variations.