Uplink Transmission Gaps for eMTC Frequency Offset Correction
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Solution Overview
Problem
Current wireless communication systems, particularly in enhanced machine type communication (eMTC), face challenges with uplink transmission gaps, which affect the ability of low-cost user equipment (UE) to correct frequency offsets due to long uplink transmission periods, leading to potential communication disruptions.
Innovation Solution
A method for uplink transmission gap negotiation between user equipment (UE) and base stations (BS), where the UE transmits a random access preamble, receives a random access response, and sends an uplink message indicating its capability to use uplink gaps, with the BS providing configuration information for uplink gap usage, enabling the UE to correct frequency errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uplink transmission periods are extended to support low-cost UE operations, then device complexity and energy consumption are reduced, but frequency offset correction capability deteriorates
Solution Approach 1:
The system performs frequency offset correction in advance during downlink reception before uplink transmission begins. The UE measures downlink frequency offset and applies compensation beforehand, eliminating the need for continuous frequency tracking during extended uplink periods.
Solution Approach 2:
The frequency correction function is segmented into separate downlink measurement and uplink transmission phases. Downlink frequency offset measurement and compensation are performed as a preliminary separate action, allowing extended uplink transmission without continuous correction mechanisms.
2Measurement precision
If uplink transmission gaps are introduced to enable frequency error correction, then frequency offset correction improves, but communication efficiency and continuity deteriorate
Solution Approach 1:
Frequency offset measurement and correction are performed preliminarily during downlink reception before uplink transmission. This eliminates the need for interrupting uplink transmission with correction gaps, as correction is already completed in advance.
Solution Approach 2:
Uplink transmission proceeds continuously without interruption for frequency correction. The useful action of data transmission maintains continuity by performing all necessary frequency compensation during the downlink phase beforehand.
3Reliability
If uplink transmission gaps are used for frequency correction, then communication reliability improves, but transmission time and latency increase
Solution Approach 1:
Frequency offset correction is performed preliminarily during downlink reception before uplink transmission begins. This advance correction ensures reliable uplink communication without requiring time-consuming correction gaps during transmission.
Solution Approach 2:
Frequency offset measurement and correction functions are merged into the downlink reception phase. By combining these functions with existing downlink operations, no additional time is required beyond what is already spent receiving downlink signals.
Data Source
AI summary
Aspects of the present disclosure provide techniques and apparatus for uplink transmission gaps in enhanced machine type communications (eMTC). In one aspect, a method is provided which may be performed by a wireless device such as a user equipment (UE), which can be a low cost eMTC UE. The method generally includes transmitting a random access preamble, receiving a random access response in response to the random access preamble, transmitting an uplink message containing an indication of a capability of the UE to transmit using uplink gaps, and receiving signaling of configuration information regarding uplink gaps.