Adaptive RLP Configuration for Multi-Carrier Wireless Systems
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Solution Overview
Problem
Current radio link protocol (RLP) systems, such as IS-99, have limitations in handling varying data services with different bandwidth, delay sensitivity, and quality of service requirements, leading to inefficient retransmission requests and suboptimal configuration for high-speed data services, especially in multi-carrier wireless communication systems.
Innovation Solution
The method involves dynamically configuring RLP parameters and selectively delaying retransmission requests to optimize data service configurations, allowing for variable sequence number lengths and retransmission counts based on communication conditions, and utilizing a delay period estimation to reduce redundant requests and improve radio capacity usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed RLP configuration is used in IS-99 systems, then the protocol implementation is simple and standardized, but the system cannot efficiently handle varying data services with different bandwidth and delay sensitivity requirements
Solution Approach 1:
The patent implements dynamic RLP configuration where parameters such as sequence number length (8 or 16 bits), maximum retransmission count, and delay period are adjusted based on communication conditions and service requirements. The system transitions from fixed IS-99 configuration to adaptive configuration that responds to channel quality, data service type, and traffic conditions, enabling efficient handling of both delay-sensitive and bandwidth-intensive services
Solution Approach 2:
The patent changes key RLP parameters dynamically: sequence number field length (8/16 bits), maximum retransmission count (variable), and delay period before retransmission request (adaptive). These parameter changes allow the system to optimize performance for different service types - e.g., using longer sequence numbers and higher retransmission counts for reliable data services while using shorter sequences and lower counts for delay-sensitive services
2Reliability
If retransmission requests are sent immediately upon detecting missing data frames, then the protocol responds quickly to errors, but redundant retransmission requests are generated when data is delayed on congested subchannels
Solution Approach 1:
The patent introduces a delay period mechanism where the receiver waits for a calculated delay time before sending retransmission requests. This preliminary waiting period allows delayed data frames (currently being transmitted on congested subchannels) to arrive, preventing premature retransmission requests. The delay period is adaptively determined based on channel conditions and service requirements
Solution Approach 2:
The patent uses a delay period estimator as an intermediary between data frame reception and retransmission request generation. This intermediary mechanism evaluates channel conditions and service requirements to determine the appropriate waiting time, acting as a buffer that prevents direct coupling between error detection and immediate retransmission, thereby reducing redundant requests
3Reliability
If the sequence number field is always 16 bits, then all data frames can be uniquely identified without restart, but the frame overhead increases reducing available data bandwidth
Solution Approach 1:
The patent dynamically changes the sequence number field length from 8 bits to 16 bits (or vice versa) based on the data service type and traffic conditions. For services requiring long data sequences or high reliability, 16-bit sequence numbers are used to avoid counter restarts. For delay-sensitive or bandwidth-constrained services, 8-bit sequence numbers are used to minimize overhead, accepting periodic counter restarts. This parameter adaptation optimizes the trade-off between identification reliability and data bandwidth efficiency
Data Source
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AI summary
A method is provided for facilitating efficient usage of radio capacity in a radio communication system including a communication station operable to receive, over a plurality of subchannels of the radio communication system. In this regard, the packet-formatted data has an overall sequence, and is divided into a plurality of portions receivable by the communication station over respective subchannels, where each portion has a respective link sequence. The method includes detecting missing packet-formatted data at the communication station based upon the overall sequence or at least one of the link sequences. Then, when the missing packet-formatted data is detected based upon the overall sequence, a time period is timed, and when the communication station fails to receive the missing packet-formatted data before the step of timing times out, retransmission of the missing packet-formatted data is requested.