RLC Status Reporting Rate Control for 8C-HSDPA Throughput
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Solution Overview
Problem
Current RLC protocols in HSDPA systems limit downlink throughput due to limitations in RLC Sequence Number space and maximum configurable PDU size, preventing support for higher data rates like 8C-HSDPA without detrimental impact on user and cell capacity.
Innovation Solution
Implementing methods in mobile terminals and RNCs to dynamically control RLC status report rates based on throughput estimates, using threshold values and timer-status-prohibit values to adjust reporting frequencies, allowing for higher bit rates while minimizing uplink capacity loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RLC status reports are sent at a high rate to support 8C-HSDPA throughput, then downlink data rate is improved, but uplink capacity is consumed and cell interference increases
Solution Approach 1:
The patent implements dynamic adjustment of RLC status report timing parameters (TSP timer values) based on current downlink throughput conditions. When throughput exceeds a threshold indicating 8C-HSDPA operation, the system automatically selects shorter TSP timer values to increase status report frequency, enabling faster ARQ retransmissions. This dynamic adaptation resolves the contradiction by making the system flexible rather than fixed, allowing optimal performance across different operating conditions.
Solution Approach 2:
The patent changes the timing parameters (TSP timer values) of the RLC status reporting mechanism based on detected throughput conditions. By monitoring downlink throughput and comparing it against thresholds, the system adjusts the TSP timer parameters to match the required data rate. This parameter change enables the system to support higher downlink rates in 8C-HSDPA mode while managing uplink resource consumption through adaptive rather than static configuration.
2Speed
If RLC status reports are sent frequently to reduce retransmission delay, then data transmission speed is improved, but uplink bit rate increases causing cell interference
Solution Approach 1:
The system dynamically adjusts status report frequency based on actual throughput needs rather than using a fixed high rate. By monitoring whether throughput exceeds the 8C-HSDPA threshold, the system only increases status report frequency when genuinely needed for high-speed operation. This prevents unnecessary uplink transmissions during lower throughput conditions, reducing cell interference while maintaining fast retransmission capability when required.
Solution Approach 2:
The patent implements parameter changes in the TSP timer values based on throughput conditions. When throughput is high (indicating 8C-HSDPA operation), shorter TSP timer values are selected to enable faster status reporting and reduce retransmission delay. When throughput is lower, longer TSP timer values are used to reduce uplink bit rate and minimize cell interference. This conditional parameter adjustment resolves the contradiction between speed and interference.
3Productivity
If RLC Sequence Number space and PDU size are increased to support higher data rates, then throughput capacity is improved, but system complexity and configuration difficulty increase
Solution Approach 1:
Instead of changing the fundamental RLC parameters (SN space, PDU size) which would increase complexity, the patent changes the operational parameters (TSP timer values) that control the timing and frequency of status reports. This approach achieves the necessary throughput support for 8C-HSDPA by optimizing the temporal characteristics of the protocol rather than its structural parameters, thereby avoiding increased system complexity while still enabling higher data rates.
Data Source
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AI summary
Techniques for signaling radio Sink control (RLC) status reports to a wireless network, such as a network supporting multi-carrier High-Speed Downlink Packet Access (HSDPA). An example method performed in a mobile terminal comprises calculating a throughput estimate data transmissions to the mobile terminal, determining a rate at which to send radio link control status reports, based on the throughput estimate K and sending radio link control status reports to the wireless network node at the determined rate. In some embodiments,, the mobile terminal determines the rate at which to send radio link contra! status reports by comparing the throughput estimate to a threshold value and selecting the rate based on the comparison. The threshold value may be received from the wireless network node prior to the comparison.