CQI RS Allocation in Multi-Antenna Systems
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Solution Overview
Problem
In multi-antenna wireless communication systems, existing methods struggle to effectively deploy and transmit reference signals as the number of antennas increases beyond the conventional 4, particularly in next-generation systems using up to 8 antennas, requiring innovative approaches to manage channel quality indication and interference.
Innovation Solution
The method involves selecting OFDM symbols in a subframe, allocating a channel quality indication reference signal (CQI RS) to non-overlapping OFDM symbols, allowing adaptive transmission based on available radio resources, and using CQI RS deployment patterns across multiple antennas to avoid interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of antennas is increased beyond 4 to 8 antennas in multi-antenna systems, then the communication capacity and data transfer rate are improved, but the deployment complexity and interference management of reference signals worsen
Solution Approach 1:
The patent segments the reference signal deployment into different OFDM symbols and resource elements across multiple antennas. Each antenna is assigned specific resource elements in a segmented manner, allowing the system to handle 8 antennas by dividing the reference signal resources rather than treating them as a monolithic complex structure
Solution Approach 2:
The patent introduces additional dimensions for reference signal deployment by utilizing both time domain (different OFDM symbols) and frequency domain (different resource elements) dimensions. This multi-dimensional approach allows efficient management of reference signals for 8 antennas by distributing them across multiple dimensions rather than concentrating them in a single dimension
2Measurement precision
If reference signals are allocated to multiple OFDM symbols for 8 antennas, then channel estimation accuracy is improved, but the overhead and resource consumption increase
Solution Approach 1:
The patent applies local quality by allocating reference signals with different properties to different antennas and resource elements. Each antenna receives appropriate reference signal resources based on its specific channel characteristics and interference environment, optimizing channel estimation accuracy locally for each antenna while managing overall overhead
Solution Approach 2:
The patent implements partial action by selectively allocating reference signals to specific OFDM symbols and resource elements rather than uniformly across all resources. This partial allocation strategy provides sufficient channel estimation accuracy for 8 antennas while avoiding excessive reference signal overhead by being selective about where reference signals are placed
3Productivity
If CQI RS is transmitted in overlapping OFDM symbols, then resource utilization is improved, but interference between reference signals increases
Solution Approach 1:
The patent uses orthogonal resource elements as intermediaries to separate CQI RS transmissions for different antennas. By assigning different resource elements (frequency-time pairs) to different antennas within the same OFDM symbol, the system enables overlapping OFDM symbol usage while preventing interference through the intermediary resource element allocation
Solution Approach 2:
The patent changes the parameters of reference signal transmission by varying the resource element assignments across different antennas and OFDM symbols. This parameter change strategy allows multiple antennas to transmit CQI RS in overlapping OFDM symbols by adjusting the frequency and time parameters of their respective reference signals to avoid collision
Data Source
AI summary
A method for transmitting a reference signal in a multi-antenna system is provided. The method includes: selecting at least one orthogonal frequency division multiplexing (OFDM) symbol in a subframe containing a plurality of OFDM symbols; allocating a channel quality indication reference signal (CQI RS) capable of measuring a channel state for each of a plurality of antennas to the selected at least one OFDM symbol; and transmitting the CQI RS, wherein the CQI RS is allocated to an OFDM symbol which does not overlap with an OFDM symbol to which a common reference signal to be transmitted to all user equipments in a cell or a dedicated reference signal to be transmitted to a specific user equipment in the cell is allocated.