Asymmetric Multi-Carrier Operation with Reverse Link Multiplexing
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Solution Overview
Problem
Existing multi-carrier wireless communication systems face challenges in providing efficient and robust asymmetric modes of operation, particularly in managing forward and reverse link carriers with varying data rate requirements and reducing reverse link overhead.
Innovation Solution
The method involves assigning a long code mask to an information channel for forward link carriers and multiplexing it on a reverse link carrier using code division multiplexing, allowing for flexible operation modes that include offsetting acknowledgement information to reduce peak-to-average ratios and combining DRC and ACK information using Walsh codewords on both I- and Q-branches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple forward link carriers are supported with unique long code masks, then system capacity and data rate are improved, but reverse link overhead and complexity increase
Solution Approach 1:
The patent combines multiple information channels (DSC, DRC, ACK) onto a single reverse link carrier using code division multiplexing with unique long code masks. This merging approach allows the system to support multiple forward link carriers while transmitting all necessary feedback information through one reverse link channel, thereby maintaining high system capacity without proportionally increasing reverse link overhead.
Solution Approach 2:
The reverse link carrier is designed to perform multiple functions simultaneously by carrying DSC information, DRC information, and ACK information all through the same physical channel. This multi-functional approach eliminates the need for separate reverse link carriers for each type of feedback, reducing overall reverse link overhead while supporting asymmetric operation modes.
2Productivity
If DSC information is multiplexed on reverse link carrier, then reverse link resource efficiency is improved, but channel complexity and difficulty of detection increase
Solution Approach 1:
The patent introduces unique long code masks as intermediary spreading codes that enable clear separation of different information channels (DSC, DRC, ACK) on the same reverse link carrier. These code masks act as mediators that allow the receiver to efficiently distinguish and detect each channel type without excessive complexity, maintaining resource efficiency while managing detection difficulty.
3Use of energy by moving object
If ACK information is offset to reduce peak-to-average ratio, then power efficiency is improved, but signal processing complexity increases
Solution Approach 1:
The patent applies periodic offset patterns to ACK information transmission to distribute peak power demands across different time periods. By periodically offsetting ACK transmissions rather than concentrating them, the system reduces the peak-to-average power ratio, improving power efficiency while the periodic nature of the offset makes the signal processing manageable through regular timing patterns.
Data Source
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AI summary
A method and system for providing asymmetric modes of operation in multi-carrier wireless communication systems. A method may assign a long code mask (LCM) to an information channel associated with a plurality of forward link carriers to transmit data from an access network to an access terminal; and multiplex the information channel on a reverse link carrier. The information channel may include one of data source channel (DSC), data rate control (DRC) and acknowledgment (ACK) information, and the multiplexing may be code division multiplexing (CDM). The A may instruct the AT on whether to multiplex the DSC information based on feedback from the AT. The method may further offset the ACK information on the reverse link to reduce the reverse link peak to average, CDM the information channel on an I-branch and on a Q-branch, and transmit the code division multiplexed information channel on the reverse link carrier.