Uplink Carrier Selection for Multi-Carrier Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face a limitation in handling uplink transmissions using multiple carriers, as they primarily utilize a single carrier for uplink physical layer channels, which restricts the benefits of frequency diversity and throughput enhancement achieved with multiple carriers in downlink transmissions.
Innovation Solution
A method and apparatus for wireless communication systems that allow WTRUs to select and manage multiple uplink carriers for transmission, performing carrier selection based on priority data, power allocation, and transmit power control to optimize uplink transmissions, enabling efficient use of multiple carriers for enhanced throughput and diversity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single carrier is used for uplink transmissions, then device complexity is reduced and ease of operation is improved, but throughput and frequency diversity benefits are limited
Solution Approach 1:
The patent segments uplink transmissions across multiple carriers, allowing different MAC-d flows to be transmitted on different carriers. This segmentation enables throughput enhancement by utilizing multiple frequency resources simultaneously while managing complexity through structured flow-to-carrier mapping rules.
Solution Approach 2:
The patent introduces a new dimension to uplink transmission by adding carrier selection capability. Instead of single-carrier transmission, the system now operates in a multi-carrier dimension, allowing WTRUs to select appropriate carriers based on flow priority, QoS requirements, and channel conditions, thereby achieving both throughput improvement and controlled complexity.
2Reliability
If multiple carriers are used for uplink transmissions, then frequency diversity and throughput are enhanced, but device complexity and power consumption increase
Solution Approach 1:
The patent applies local quality by allowing different MAC-d flows to be transmitted on different carriers based on their specific QoS requirements and priority levels. High-priority flows can be transmitted on carriers with better channel conditions, while lower-priority flows use other carriers, thereby achieving frequency diversity for reliability while optimizing power consumption through selective transmission.
Solution Approach 2:
The patent changes the parameter of carrier selection dynamically based on flow priority, QoS requirements, and channel conditions. WTRUs can adaptively select carriers for different flows, changing the transmission parameters to optimize both reliability through frequency diversity and power consumption by avoiding unnecessary multi-carrier transmissions when not required.
3Productivity
If multiple carriers are used for uplink transmissions, then network efficiency and QoS are improved, but scheduling complexity and resource management difficulty increase
Solution Approach 1:
The patent applies preliminary action by establishing predefined rules and criteria for carrier selection before transmission occurs. Network entities configure flow-to-carrier mappings, QoS parameters, and priority levels in advance, allowing WTRUs to autonomously select appropriate carriers based on pre-configured rules rather than requiring complex real-time scheduling decisions, thereby improving network efficiency while managing scheduling complexity.
Data Source
AI summary
A method and an apparatus for uplink transmission using multiple uplink carriers are disclosed. A wireless transmit/receive unit (WTRU) selects a dedicated channel medium access control (MAC-d) flow with highest priority data to be transmitted and performs uplink carrier selection and enhanced dedicated channel (E-DCH) transport format combination (E-TFC) restriction and selection to select a carrier among a plurality of carriers and select an E-TFC based on a maximum supported payload, a remaining scheduled grant payload of the selected carrier and a remaining non-scheduled grant payload. The WTRU then generates a medium access control (MAC) protocol data unit (PDU) for E-DCH transmission via the selected carrier based on the selected E-TFC.