Antenna Subsets for Reduced Channel Estimation
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Solution Overview
Problem
Conventional mobile communications systems, such as those based on LTE, require complex channel estimation for receivers to detect data from multiple antennas, which increases processing load and costs, making it challenging for simpler, low-cost devices like MTCs to effectively receive signals in challenging radio conditions.
Innovation Solution
The infrastructure equipment transmits reference signals from multiple antennas in different communications resource elements, allowing receivers to estimate channels with reduced complexity by switching data segments between subsets of antennas in time or frequency, thereby reducing the number of channel estimates required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signals are transmitted from multiple antennas simultaneously in the same resource elements, then data transmission reliability is improved through antenna diversity, but receiver complexity increases due to the need for sophisticated detection techniques and multiple channel estimates
Solution Approach 1:
The data stream is segmented into multiple data segments that are transmitted from different antenna subsets at different times or frequencies. Each data segment is associated with a specific antenna subset, allowing the receiver to process one antenna's signal at a time rather than simultaneously processing multiple antenna signals, thus reducing receiver complexity while maintaining diversity benefits
Solution Approach 2:
The infrastructure equipment periodically switches between different antenna subsets to transmit different data segments. This time-division or frequency-division approach creates a periodic transmission pattern where each antenna subset transmits in designated time slots or frequency resources, enabling the receiver to use simpler detection techniques adapted to this periodic structure
2Reliability
If antenna diversity techniques are employed to improve signal integrity, then transmission reliability is enhanced, but the cost and complexity of the communications device increases
Solution Approach 1:
By segmenting data transmission across different antenna subsets and time/frequency resources, the system provides diversity benefits without requiring the receiver to implement complex simultaneous multi-antenna detection algorithms, thereby reducing manufacturing costs for simple MTC devices
Solution Approach 2:
The patent enables simple, low-cost receiver designs that can be manufactured inexpensively for MTC applications. The receiver uses basic detection techniques rather than sophisticated algorithms, making the device comparable to disposable or low-cost components while still achieving reliable communication through the structured antenna switching approach
3Measurement precision
If multiple channel estimates are required for data detection from multiple antennas, then detection accuracy is improved, but processing load and computational complexity increase
Solution Approach 1:
The channel estimation process is segmented by antenna subset and time/frequency resource. Instead of estimating channels from all antennas simultaneously across all resources, the receiver estimates channels for the active antenna subset in the current time slot or frequency resource, significantly reducing the number of concurrent channel estimates required and lowering processing load
Data Source
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AI summary
An infrastructure equipment for a mobile communications network includes a plurality of antennas, and is configured, in a first mode of operation, to transmit, from each of the plurality of antenna, reference signals in communications resource elements of the wireless access signals allocated to each of the plurality of antennas. The reference signals are transmitted from each of the antennas in different communications resource elements of the wireless access interface for each antenna, so that a receiver can estimate a communications channel for each of the plurality of antenna, from the antenna to the receiver, from the transmitted reference signals. The infrastructure equipment transmits in the first mode of operation, from each of the plurality of antennas, signals representing data in communications resource elements allocated for transmitting the data to one of the communications devices, the signals representing the data being transmitted contemporaneously in the same communications resource elements from each antenna. In a second mode of operation, the infrastructure equipment is configured to determine a mapping for transmitting different data segments from each of a plurality of subsets of the plurality antennas to a second communications device using communications resource elements, which, for each antenna subset, are separated in at least one of time or frequency and to transmit an indication of the mapping for transmitting the data segments from each of the subsets of antennas to the second communications device. The infrastructure equipment is configured to switch between transmitting signals representing the different data segments between the subsets of the plurality of antennas to the second communications device, the signals being transmitted from each antenna subset representing different data segments for transmission to the second communications device, the transmitted signals being switched in at least one of time or frequency in accordance with the mapping so that to detect the data a receiver is required to generate a smaller number of channel estimates than the receiver would be required to estimate if the data was transmitted in the first mode. The communications resource elements which are used to transmit the reference signals from each antenna are the same in the first mode of operation as the second mode of operation.