Pilot Symbol Allocation in MIMO Wireless Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In MIMO multi-carrier wireless communication systems, existing methods face challenges in channel estimation due to interference between pilot symbols transmitted from multiple antennas, leading to degraded performance in synchronization, signal detection, and frequency offset estimation.
Innovation Solution
The method involves generating multiple pilot symbol sequences based on a basic code sequence and processing them for allocation to multiple carriers, with each sequence being transmitted through a corresponding antenna, allowing for independent channel estimation and reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the same pilot symbol is transmitted from multiple transmitting antennas in a MIMO system, then the transmission quantity of data is increased, but interference exists between the transmitted pilot symbols which degrades channel estimation accuracy
Solution Approach 1:
The patent divides the single pilot symbol sequence into multiple distinct pilot symbol sequences, with each sequence assigned to a specific transmitting antenna. This segmentation allows the receiver to separately estimate channels from each antenna without interference, as each antenna transmits its own unique pilot sequence rather than repeating the same sequence.
Solution Approach 2:
The patent assigns different local qualities (distinct pilot symbol sequences) to different transmitting antennas. Each antenna is given a unique pilot sequence characteristic that allows the receiver to identify and separately process signals from each antenna, thereby eliminating interference while maintaining high data transmission capacity.
2Productivity
If pilot symbols are allocated between data subcarriers to increase data transmission, then the transmission quantity of data is increased, but the density of pilot symbols decreases which degrades channel estimation efficiency
Solution Approach 1:
The patent resolves the contradiction by introducing a new dimension - the antenna dimension. Instead of competing for the same frequency-time resources, multiple pilot sequences are separated by assigning them to different transmitting antennas. This allows high data transmission on data subcarriers while maintaining high channel estimation efficiency through dedicated pilot sequences on each antenna.
3Measurement precision
If a preamble with high density of pilot symbols is used for channel estimation, then channel estimation accuracy is improved, but the transmission quantity of data is reduced due to guard intervals and pilot overhead
Solution Approach 1:
The patent segments the channel estimation function across multiple antennas, each transmitting dedicated pilot sequences. This allows the system to maintain high channel estimation accuracy through antenna-specific pilot sequences while minimizing the overhead impact on data transmission, as each antenna's pilot sequence is efficiently utilized for its corresponding channel estimation.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A method of transmitting pilot symbols is disclosed. In a communication system performing communications using a plurality of antennas and multiple carriers, the present invention includes the steps of generating a plurality of pilot symbol sequences based on a basic code sequence, data-processing a plurality of the pilot symbol sequences by allocating each of a plurality of the pilot symbol sequences to the multiple carriers, and transmitting each of a plurality of the data-processed pilot symbol sequences via a corresponding one of a plurality of the antennas.