Uplink Grant Sounding Trigger via Unused States
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Solution Overview
Problem
In wireless communication systems, particularly in LTE and LTE-Advanced, there is a need to efficiently trigger uplink sounding using Demodulation Reference Signals (DMRS) without concurrent data transmission on the Physical Uplink Shared Channel (PUSCH), which current methods fail to address effectively, leading to inefficiencies and increased complexity for single antenna port UEs.
Innovation Solution
The method involves using existing unused states in information elements within the Uplink grant, such as Precoder Matrix Index - Rank Index (PMI/RI) and Modulation and Coding Selection (MCS), to trigger sounding without adding additional overhead, by encoding specific states as requests for sounding, allowing for the reuse of unutilized DMRS cyclic shifts for sounding transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional information elements or bits are added to trigger sounding, then sounding can be dynamically activated, but overhead in the UL grant increases
Solution Approach 1:
The patent makes existing information elements in the UL grant (such as PMI/RI and MCS) serve dual purposes: their original functions for data transmission scheduling and an additional function for triggering aperiodic sounding. By reusing these existing fields to carry sounding trigger indications, the system achieves dynamic sounding activation without adding dedicated overhead bits, thus resolving the contradiction between adaptability and overhead.
2Adaptability or versatility
If multiple UL grant formats are used for single antenna port UEs, then all UEs can be supported, but system complexity increases
Solution Approach 1:
The patent enables a single UL grant format to support both single antenna port UEs and multi-antenna UEs by making the information elements serve multiple functions. The same grant format can trigger sounding for single antenna UEs while simultaneously providing scheduling information for multi-antenna UEs, eliminating the need for separate grant formats and reducing system complexity.
Solution Approach 2:
The patent changes the interpretation or state of existing parameters (PMI/RI, MCS) to convey different meanings. By utilizing unused states or reinterpreting existing parameter combinations, the system can indicate sounding triggers without changing the fundamental grant format structure, thus supporting different UE types with a unified format.
3Productivity
If unused DMRS cyclic shifts are reused for sounding, then resource utilization improves, but interference management becomes more challenging
Solution Approach 1:
The patent changes the parameter state by utilizing previously unused or underutilized DMRS cyclic shifts for sounding transmissions. This reparameterization of the cyclic shift resource allows the system to increase SRS utilization without requiring additional orthogonal resources, effectively resolving the contradiction between resource utilization and interference management by using previously idle resource states.
Data Source
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AI summary
Uplink sounding comprising sending one or more representations of a sounding request or a sounding request and configuration information indicator of uplink sounding in a wireless radio communication system is disclosed.