Uplink SRS Sub-channel Allocation for MTC Bandwidth Reduction
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Solution Overview
Problem
Machine Type Communication (MTC) devices face challenges in reducing radio frequency bandwidth usage to communicate effectively within traditional LTE systems, limiting their ability to use existing uplink or downlink resource mappings, which affects their cost and operational efficiency.
Innovation Solution
The method involves allocating a first uplink sub-channel to an MTC device for SRS transmission, determining a preferred uplink sub-channel based on received SRS transmissions, and configuring frequency hopping to optimize SRS frequency positions, allowing the MTC device to operate with a reduced bandwidth while maintaining communication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If MTC devices use reduced radio frequency bandwidth to reduce cost and power consumption, then device cost and energy efficiency are improved, but the ability to use existing uplink or downlink resource mappings deteriorates
Solution Approach 1:
The system segments the uplink bandwidth into multiple uplink sub-channels, each capable of carrying SRS transmissions. This segmentation allows MTC devices with reduced RF bandwidth to operate on specific sub-channels while the overall system maintains full bandwidth capability, resolving the contradiction between device bandwidth reduction and system resource mapping compatibility
Solution Approach 2:
The patent introduces a new dimension to SRS resource allocation by enabling SRS transmissions on uplink sub-channels that are separate from traditional uplink data channels. This dimensional separation allows MTC devices to use reduced bandwidth for control signaling while traditional UEs continue using full bandwidth for data transmissions, maintaining compatibility across different device types
2Measurement precision
If MTC devices are allocated specific uplink sub-channels for SRS transmission, then channel measurement precision is improved, but device complexity increases
Solution Approach 1:
The system enables self-service by allowing MTC devices to autonomously select and transmit SRS on appropriate uplink sub-channels based on simple configuration parameters received from the base station. The devices do not require complex processing to determine SRS resources, as the network provides clear allocation instructions, thereby maintaining low device complexity while achieving precise channel measurements
3Measurement precision
If frequency hopping is configured for SRS transmissions, then channel measurement coverage is improved, but signaling overhead increases
Solution Approach 1:
The patent applies local quality by configuring frequency hopping parameters specifically for MTC devices based on their individual channel conditions and service requirements. Not all devices require the same hopping configuration, allowing the system to optimize measurement coverage for each device while minimizing unnecessary signaling overhead for devices with stable channel conditions
Data Source
AI summary
According to some embodiments, a method of operating a wireless device in a wireless system comprises allocating a first uplink sub-channel to the wireless device in a first subframe associated with the wireless device. The first uplink sub-channel comprises a portion of an uplink system bandwidth, and portions of the uplink system bandwidth outside of the first uplink sub-channel are not available for transmission in the first subframe by the wireless device. The method further comprises determining a first sounding reference signal (SRS) sub-channel. The first SRS sub-channel comprises a portion of the first uplink sub-channel in frequency domain, and the SRS sub-channel is available for transmitting SRS in the first subframe by the wireless device.