SRS Transmission in Special Subframes for Massive MIMO
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Solution Overview
Problem
The existing solutions for sending a Sounding Reference Signal (SRS) in LTE and LTE-Advanced systems are imperfect, particularly in scenarios involving multiple antennae and time-domain symbol usage, which limits the number of users that can be multiplexed and does not effectively meet the requirements of full-dimension-MIMO or massive-MIMO configurations.
Innovation Solution
The method involves sending an SRS on a time-domain symbol of a special subframe, specifically utilizing one or more time-domain symbols occupied by an UpPTS, with the number of such symbols ranging from 3 to 12, and determining the time-domain symbol location based on the parity or range of the subframe sequence number, or predefined configuration information including SRS sending period and subframe offset configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing SRS sending solutions are used in LTE and LTE-Advanced systems, then the system can maintain basic compatibility, but the number of users that can be multiplexed is limited and full-dimension-MIMO or massive-MIMO configurations cannot be effectively supported
Solution Approach 1:
The patent extends SRS transmission from traditional uplink subframes to include UpPTS (Uplink Pilot Time Slot) in special subframes, adding a new time dimension for SRS transmission. This allows SRS to be sent in both regular uplink subframes and special subframes, effectively increasing the time resources available for SRS and enabling support for more users and advanced MIMO configurations without interfering with existing uplink-downlink scheduling
Solution Approach 2:
The patent introduces dynamic configuration mechanisms where the network can flexibly configure whether SRS is transmitted in UpPTS based on traffic conditions, user requirements, and system load. The SRS transmission in UpPTS can be dynamically activated or deactivated, allowing the system to adapt to changing conditions and optimize performance for different scenarios including full-dimension-MIMO and massive-MIMO deployments
2Productivity
If additional time-domain symbols are utilized for SRS transmission in UpPTS, then SRS sending capability and user multiplexing are improved, but the system complexity increases due to additional configuration and coordination requirements
Solution Approach 1:
The patent modifies existing SRS configuration parameters to accommodate UpPTS transmission. It reuses and extends parameters such as srs-ConfigIndex, srs-SubframeConfig, and srs-ConfigZero to control SRS transmission in both regular uplink subframes and UpPTS. By parameterizing the configuration, the system can enable or disable UpPTS SRS transmission without changing the fundamental protocol structure, thus managing complexity while improving capability
Solution Approach 2:
The patent makes the existing SRS configuration mechanism universal by enabling it to handle both traditional uplink subframe SRS transmission and the new UpPTS SRS transmission. The same configuration parameters and signaling mechanisms are used for both cases, eliminating the need for separate dedicated configuration systems and reducing overall system complexity despite the enhanced functionality
Data Source
AI summary
The invention provides a method of transmitting a sounding reference signal (SRS) and a device utilizing the same. The method comprises: a user equipment transmits, to a base station, a sounding reference signal (SRS) on a time domain symbol in a special subframe, wherein the time domain symbol comprises one or more time domain symbols of time domain symbols occupying an uplink pilot time slot; and a number of the time domain symbols occupying the uplink pilot time slot is N, N is an integer, and 3≤N≤12. The embodiment resolves a problem of an incomplete scheme of transmitting an SRS on a time domain symbol, and realizes transmission of an SRS on increased time domain symbols.