Dual Band Transmission Reliability via ARQ Fallback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing techniques for protecting uplink and downlink transmissions in cellular networks, particularly in unlicensed spectrum using LAA-LTE, face challenges in reliability due to shared medium access and interference from other devices, leading to unpredictable ARQ processes.
Innovation Solution
A communication device and method that employ dual frequency bands, using a first automatic repeat request (ARQ) scheme in a licensed frequency band and a second ARQ scheme in an unlicensed frequency band, with fallback mechanisms based on acknowledgement status to ensure reliable data packet transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LAA-LTE is used to transmit data packets in unlicensed frequency bands, then spectrum utilization is improved and capacity is augmented, but transmission reliability deteriorates due to shared medium access and interference from third parties
Solution Approach 1:
The patent changes the parameter of frequency band selection dynamically. The system monitors acknowledgment status of data packets transmitted in unlicensed bands and switches the frequency band parameter (from unlicensed to licensed) when transmission reliability deteriorates, thereby maintaining both high spectrum utilization and acceptable transmission reliability
Solution Approach 2:
The patent introduces an intermediary mechanism (acknowledgment checking and frequency band switching) between the data packet transmission and the unlicensed medium. This intermediary monitors transmission success and mediates the selection between licensed and unlicensed bands, protecting against the harmful effects of uncontrolled shared medium access
2Reliability
If ARQ scheme is implemented in unlicensed bands with shared medium access, then transmission protection is provided, but the ARQ process becomes less predictable due to uncontrolled medium usage
Solution Approach 1:
The patent makes the ARQ process dynamic by conditionally applying it based on frequency band and acknowledgment status. The system dynamically adjusts whether to apply ARQ retransmission in unlicensed bands or switch to licensed bands, making the overall process more predictable despite the underlying uncontrolled medium
Solution Approach 2:
The patent segments the ARQ process into two distinct paths: one for unlicensed bands with limited retransmission attempts and one for licensed bands with full ARQ protection. This segmentation allows each path to be optimized independently, improving overall predictability
3Reliability
If data packets are retransmitted in unlicensed frequency bands, then transmission reliability is improved, but signaling load on the licensed LTE band increases
Solution Approach 1:
The patent applies partial ARQ action in unlicensed bands by limiting the number of retransmission attempts rather than implementing full ARQ protection. This partial action reduces signaling load on the licensed band while still providing some transmission reliability improvement in unlicensed bands
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Communication between a cellular network (102) and a communication device (101 ) occurs in a first frequency band (1 1 1 ) and a second frequency band (1 12), the second frequency band (1 12) being at least partly different from the first frequency band (1 1 1 ). A data packet is sent in the first frequency band (1 1 1 ). Depending on an acknowledgment of receipt of the data packet, the data packet is selectively sent in the second frequency band (1 12).