UMTS Compressed Mode Gap Patterns for Voice Services
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Solution Overview
Problem
The existing compressed mode operation for dedicated channel DCH in circuit switched CS voice services is not compatible with the uplink control channel structure, leading to inefficient transmission gaps and inadequate support for network measurements, particularly for LTE systems.
Innovation Solution
Implementing a Frame Early Termination (FET)-less operation for uplink transmission, where voice frames are transmitted in 10 ms, and only the uplink control channel is transmitted until downlink acknowledgement, ensuring a guaranteed 14-slot gap, and power boosting to compensate for reduced slots during compressed mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the typical compressed mode gap pattern (14-slot gap) is used for CS voice services, then measurement gaps are provided for inter-frequency measurements, but the uplink control channel structure cannot transmit all TFCI information (only 8 slots available instead of required 10 slots)
Solution Approach 1:
The patent applies dynamics by making the compressed mode gap pattern adaptable to different service requirements. Specifically, it introduces a new gap pattern (pattern 2) with 6 slots before gap and 8 slots after gap, which is dynamically selected based on whether the service is CS voice or packet data. This dynamic adaptation resolves the contradiction by providing sufficient slots for TFCI transmission in packet data services while maintaining measurement capabilities.
Solution Approach 2:
The patent changes the parameter of gap pattern configuration from a fixed 14-slot gap to multiple configurable patterns. By introducing different gap patterns with varying slot distributions (pattern 1: 14-slot gap, pattern 2: 6+8 slot distribution, pattern 3: 8+6 slot distribution), the system can adjust the number of slots allocated to control channel transmission versus measurement, thereby resolving the information loss problem while preserving measurement functionality.
2Measurement precision
If the compressed mode with 14-slot gap is used, then measurement gaps are guaranteed, but the data transmission efficiency is reduced due to loss of slots
Solution Approach 1:
The patent applies local quality by optimizing the gap structure specifically for different service types rather than using a uniform approach. For packet data services, it uses pattern 2 or 3 which distribute gap slots more favorably for data transmission. For CS voice services, it maintains pattern 1 which guarantees measurement gaps. This localized optimization resolves the contradiction by improving data transmission efficiency where possible while maintaining measurement guarantees where required.
Solution Approach 2:
The system dynamically selects different gap patterns based on service type requirements. The network can switch between pattern 1, 2, and 3 depending on whether the active service is CS voice or packet data, thereby optimizing data transmission efficiency for packet data while maintaining measurement gap guarantees for voice services.
3Loss of information
If the enhanced DCH structure requiring 10 slots for TFCI is used, then complete control information can be transmitted, but the typical compressed mode gap pattern provides only 8 slots
Solution Approach 1:
The patent makes the gap pattern dynamic and service-dependent. For packet data services where complete TFCI information is critical, it selects pattern 2 or 3 that provide at least 8 slots before gap (plus additional slots after gap), ensuring sufficient space for control information. This dynamic selection resolves the contradiction by providing complete control information transmission when needed without permanently increasing transmission time.
Solution Approach 2:
The patent changes the temporal parameters of the gap structure by introducing multiple patterns with different slot distributions. By adjusting the number of slots before and after the gap, the system can provide sufficient time for complete TFCI information transmission (10 slots) in packet data services while maintaining the measurement gap functionality in voice services.
Data Source
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AI summary
The present invention addresses methods, apparatuses and computer program products for improved compressed mode operation for enhanced dedicated channel DCH in circuit switched CS voice services/transmissions. A compressed mode of a user equipment is configured during performing a circuit switched voice service over a dedicated channel according to Wideb and Code-Division Multiple Access operation upon demand for network specific measurement, whereby measurement gaps are created in the data transmission. In uplink, transmission of a voice frame to be compressed is performed using a 10ms transmission, whereas in downlink, transmission of a voice frame to be compressed is stopped after a fixed number of slots have been transmitted, wherein the fixed number of slots is set such as to ensure a measurement gap with at least 14 slots.