Uplink Coverage Enhancements via TTI Bundling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems face challenges in enhancing uplink coverage, particularly for low-cost devices with machine type communications, as existing physical uplink control channels and random access channels have limitations in carrying data efficiently over multiple transmission time intervals (TTIs).
Innovation Solution
The technique involves bundling uplink control channels over multiple TTIs, using various channel formats such as PUCCH format 1a/1b, PUCCH format 3, and aggregating physical uplink control channels and physical random access channels, with outer coding for error protection, and selecting TTI bundling size based on payload size, interference level, and target latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If uplink control channels are transmitted using a single transmission time interval (TTI), then the transmission delay is reduced, but the uplink coverage is limited and the number of transmittable bits is insufficient
Solution Approach 1:
The patent segments the uplink control channel transmission across multiple TTIs, dividing the data payload into portions transmitted in different time intervals. This allows the system to transmit more bits overall by utilizing multiple transmission opportunities while maintaining low latency through efficient segmentation and parallel processing of the segmented data.
2Quantity of substance
If the uplink control channel bandwidth is increased to transmit more data, then the number of transmittable bits increases, but the device complexity and hardware requirements increase
Solution Approach 1:
The patent transitions from increasing bandwidth (frequency dimension) to utilizing multiple transmission time intervals (time dimension) as the primary method for increasing data capacity. This dimensional shift allows more bits to be transmitted without requiring additional frequency resources or complex hardware, instead leveraging time-domain multiplexing and efficient TTI bundling mechanisms.
3Reliability
If multiple channel formats are aggregated to enhance coverage, then the uplink coverage is improved, but the device complexity and processing overhead increase
Solution Approach 1:
The patent merges multiple channel formats (PUCCH format 1a/1b, PUCCH format 3, and PRACH) into a unified TTI bundling framework. This consolidation allows the system to leverage the strengths of each format while managing processing overhead through standardized bundling procedures, joint decoding mechanisms, and coordinated resource allocation that simplifies the overall processing complexity despite using multiple formats.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Aspects of the present disclosure provided techniques for enhancing uplink coverage. A method for wireless communications by a wireless device is provided. The method generally includes obtaining a payload of data to be transmitted to a base station, selecting at least one uplink control channel and a number of transmission time intervals (TTIs), and conveying the data in the at least one uplink control channel over the number of TTIs, wherein different portions of the data are conveyed in different TTIs.