Multi-mode WTRU UCI Multiplexing Across LTE and HSPA
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Solution Overview
Problem
Wireless communication systems face challenges in optimizing network coverage and capacity, particularly due to underutilization of radio resources and spectrum, especially when transitioning between different radio access technologies like LTE and HSPA, where carrier aggregation is limited, leading to inefficiencies in bandwidth usage and capacity utilization.
Innovation Solution
A multi-mode wireless transmit/receive unit (WTRU) capable of operating on multiple component carriers across various radio access technologies (RATs) is developed to send uplink control information (UCI) by multiplexing UCI from different RATs onto a single carrier, prioritizing UCI transmission based on specific rules, and using different frequencies to enhance bandwidth usage and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If carrier aggregation is limited to 2-3 component carriers per RAT, then device complexity is reduced, but bandwidth usage and capacity utilization deteriorate
Solution Approach 1:
The patent enables a single uplink carrier to serve multiple RATs (LTE and HSPA) simultaneously by multiplexing UCI from different RATs onto the same physical uplink resources. This multi-functional approach allows the uplink channel to handle control information for both LTE and HSPA without requiring separate dedicated carriers for each RAT, thereby increasing bandwidth utilization while maintaining manageable device complexity.
Solution Approach 2:
The patent combines UCI transmission resources for multiple RATs into a single shared uplink carrier. By merging the control channels of LTE and HSPA onto the same physical uplink resources, the system achieves more efficient spectrum utilization and avoids the underutilization that occurs when each RAT has limited dedicated carriers.
2Reliability
If separate uplink carriers are allocated for each RAT, then reliability of UCI transmission is improved, but loss of time and resource underutilization worsen
Solution Approach 1:
The patent introduces a multiplexing mechanism that acts as an intermediary between multiple RATs and the shared uplink carrier. This mediator manages the allocation and prioritization of UCI from different RATs (LTE and HSPA) on the same physical resources, ensuring reliable transmission while maximizing resource utilization and avoiding the time loss associated with idle carriers.
3Quantity of substance
If carrier aggregation supports more component carriers, then bandwidth usage improves, but device complexity increases
Solution Approach 1:
Instead of allocating separate dedicated carriers for each RAT's control information, the patent makes a single uplink carrier universal by enabling it to carry UCI from multiple RATs simultaneously. This approach achieves high bandwidth utilization without requiring the device to manage multiple separate carrier allocations, thereby avoiding the complexity increase that would result from extensive carrier aggregation.
Data Source
AI summary
A method and apparatus for sending uplink control information by a multi-mode wireless transmit/receive unit (WTRU) including receiving radio resource control (RRC) configuration information indicating use of a first transmission for uplink control information (UCI) for a first group of downlink carriers and use of a second transmission for UCI for a second group of downlink carriers. The WTRU receives, in a downlink control channel, a message explicitly indicating a timing for transmitting UCI for the first group of downlink carriers and transmitting UCI for transmitting UCI for the second group of downlink carriers and transmits the UCI for the different carriers according to the indicated timing.