Wireless Relay ACK/NACK Multiplexing for UL Resource Efficiency
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Solution Overview
Problem
In wireless communication systems using high-frequency bands, the coverage area is reduced due to signal attenuation with increased transmission distance, necessitating more base stations, and the TD relay technique faces inefficiencies in using UL resources due to timing overlaps between backhaul and access link allocations.
Innovation Solution
A wireless communication device and method that determine and multiplex ACK/NACK signals in available subframes, allowing efficient use of UL resources by identifying suitable subframes for access link allocation based on process delays and backhaul UL grant availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If TD relay technique is used to extend coverage area, then the coverage area is improved, but the UL resource usage efficiency deteriorates due to timing overlaps between backhaul and access link allocations
Solution Approach 1:
The patent applies dynamics by making the relay station's transmission/reception timing adaptive rather than fixed. The relay station dynamically determines whether to transmit or receive in each subframe based on real-time availability of backhaul UL grants and access link allocation status, allowing the system to flexibly adjust to varying traffic conditions and resolve timing conflicts between backhaul and access links
Solution Approach 2:
The patent changes the parameter of subframe allocation timing by allowing the relay station to transmit ACK/NACK in subframes that are not strictly predetermined. By modifying the timing parameter based on the actual allocation status of backhaul UL grants and access links, the system avoids resource conflicts and improves overall UL resource usage efficiency while maintaining extended coverage
2Reliability
If more base stations are installed to compensate for signal attenuation, then the communication reliability is improved, but the system cost increases
Solution Approach 1:
The patent introduces a relay station as an intermediary device between the base station and mobile stations. This relay station receives signals from the base station and retransmits them to mobile stations in areas with poor direct coverage, effectively extending the base station's coverage area without requiring additional base stations, thereby maintaining communication reliability while reducing system cost
Solution Approach 2:
The patent extends the coverage area by adding a spatial dimension through relay stations deployed at intermediate locations. Instead of installing more base stations at the network core, the solution distributes relay stations throughout the coverage area, creating a hierarchical network structure that reduces the number of expensive base station installations while maintaining comprehensive coverage and reliability
Data Source
AI summary
A wireless communication device according to the invention includes a reception section that receives a downlink signal in a first subframe from another wireless communication device; an ACK/NACK generation section that generates ACK/NACK which indicates an error determination result of the received downlink signal; a determination section that determines, when an uplink signal directed to the other wireless communication device is not allocated in a second subframe, whether a different uplink signal is allocated in a third subframe subsequent to the first subframe by a predetermined number of subframes and previous to the second subframe; a multiplexing section that multiplexes the ACK/NACK to the different uplink signal in the third subframe when the determination section determines that the different uplink signal is allocated in the third subframe; and a transmission section that transmits the different uplink signal in which the ACK/NACK is multiplexed by the multiplexing section.