W-CDMA Transport Channel Puncturing for Capacity Gain
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless communications systems, particularly those using W-CDMA, face challenges in reducing transmission power and increasing capacity due to redundancy techniques that enhance error correction but reduce system capacity when signal reception conditions are good.
Innovation Solution
Implementing a method that multiplexes multiple transport channels to create a composite channel, transmits symbols during a specific time interval, receives acknowledgment messages, and punctures symbols for acknowledged channels to terminate transmission early, thereby reducing unnecessary transmission and increasing system capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If symbol redundancy techniques are used to guard against errors in received signals, then reliability of data transmission is improved, but transmission power consumption increases and system capacity decreases
Solution Approach 1:
The patent implements dynamic puncturing where the transmission scheme adapts based on ACK feedback. When ACK is received indicating successful reception, subsequent symbols for that transport channel are punctured (removed). This dynamic adjustment allows the system to transition from redundant transmission to minimal transmission based on real-time channel conditions, reducing power consumption while maintaining reliability.
Solution Approach 2:
The patent changes the transmission parameter (symbol presence/absence) based on reception status. By using ACK messages to trigger puncturing operations, the system modifies the effective transmission rate and redundancy level dynamically. This parameter change allows optimization of power usage - full redundancy when needed, minimal redundancy when channel conditions are good.
2Reliability
If symbol redundancy techniques are used to guard against errors in received signals, then reliability of data transmission is improved, but system capacity decreases
Solution Approach 1:
The system dynamically adjusts the amount of redundancy transmitted based on ACK feedback. When data is successfully received (ACK received), the system punctures subsequent symbols, effectively reducing redundancy. This dynamic behavior allows the system to maintain high reliability when needed while maximizing capacity during periods of good channel conditions, thus resolving the contradiction between reliability and system capacity.
Solution Approach 2:
The patent implements parameter changes in the form of puncturing patterns. The effective coding rate and redundancy level are modified based on ACK reception. This allows the system to operate at different points on the reliability-capacity tradeoff curve, achieving high capacity when channel conditions permit while maintaining reliability through selective redundancy.
3Reliability
If full transmission time interval is used for all transport channels, then data integrity is ensured, but transmission efficiency decreases
Solution Approach 1:
The patent uses preliminary ACK feedback to determine whether subsequent transmission is needed. By receiving ACK messages during the TTI, the system can proactively puncture remaining symbols for successfully received transport channels. This preliminary action based on feedback ensures data integrity for acknowledged channels while improving efficiency by eliminating unnecessary transmissions.
Solution Approach 2:
The patent extracts and removes (punctures) symbols from the transmission stream for transport channels that have been successfully received and acknowledged. This extraction of unnecessary symbols maintains data integrity for required channels while removing redundant transmissions, thereby improving overall transmission efficiency without compromising necessary data delivery.
Data Source
AI summary
Techniques to increase the capacity of a W-CDMA wireless communications system. In an exemplary embodiment, early termination (400) of one or more transport channels on a W-CDMA wireless communications link is provided. In particular, early decoding (421, 423) is performed on slots as they are received over the air, and techniques are described for signaling (431, 432) acknowledgment messages (ACK's) for one or more transport channels correctly decoded to terminate the transmission of those transport channels. The techniques may be applied to the transmission of voice signals using the adaptive multi-rate (AMR) codec. Further exemplary embodiments describe aspects to reduce the transmission power and rate of power control commands sent over the air, as well as aspects for applying tail-biting convolutional codes (1015) in the system.