Adaptive Preamble Length for Uplink Control Channels
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Solution Overview
Problem
In mobile/wireless communications, continuously transmitting control channels during periods of inactivity leads to significant overhead and power consumption, especially in bursty packet services, affecting uplink capacity and power control accuracy.
Innovation Solution
Adaptive preamble length adjustment for control channels based on multipath fading, throughput, and transmission gap length, allowing for optimized power control and channel estimation while minimizing unnecessary transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DPCCH is continuously transmitted during periods of inactivity, then power control accuracy and channel estimation are maintained, but control overhead and power consumption increase significantly
Solution Approach 1:
The patent implements dynamic DPCCH transmission by adjusting the preamble length based on channel conditions, throughput requirements, and transmission gap length. The system transitions from continuous transmission to adaptive discontinuous transmission, where the DPCCH is transmitted only when necessary with optimized preamble lengths (1-4 slots), thereby reducing power consumption while maintaining power control accuracy through conditional transmission based on fading degree and channel state
Solution Approach 2:
The patent changes the transmission parameters of DPCCH by dynamically adjusting preamble length according to multiple criteria including degree of fading, throughput relative to nominal throughput, and transmission gap length. This parameter adaptation allows the system to maintain reliability when needed while minimizing overhead during stable conditions, directly addressing the contradiction between continuous transmission reliability and energy efficiency
2Reliability
If DPCCH is continuously transmitted, then power control and channel estimation are maintained, but uplink capacity is reduced due to control overhead
Solution Approach 1:
The system dynamically adjusts DPCCH transmission based on actual channel conditions and traffic patterns. By using adaptive preamble length (1-4 slots) rather than continuous transmission, the system maintains channel estimation accuracy when channel conditions warrant it while freeing up uplink resources for data transmission during stable conditions, thereby increasing overall uplink capacity
Solution Approach 2:
The patent applies partial action by transmitting DPCCH only to the extent necessary for maintaining reliability. Instead of continuous transmission, the system uses selective transmission with optimized preamble lengths based on fading degree and transmission gap length, providing just enough control signaling to maintain channel estimation accuracy while minimizing overhead that would reduce uplink capacity
3Loss of energy
If transmission gap is increased to reduce overhead, then power savings and capacity increase, but power control accuracy deteriorates
Solution Approach 1:
The system dynamically adjusts preamble length in response to transmission gap length and channel conditions. When transmission gaps occur, the system transmits DPCCH with optimized preamble lengths (1-4 slots) to maintain power control accuracy during the gap and upon resumption, thereby achieving power savings through discontinuous transmission while preventing deterioration of power control precision through adaptive preamble transmission
Solution Approach 2:
The patent uses preliminary action by transmitting optimized DPCCH preambles before and during transmission gaps to maintain power control state information. This preliminary and conditional transmission ensures that when transmission resumes after gaps, power control accuracy is maintained without requiring continuous DPCCH transmission, thus achieving both power savings and measurement precision
Data Source
AI summary
The specification and drawings present a new method, system, apparatus and software product for defining an adaptive preamble length of a preamble for a continuous connectivity transmission using a control channel, e.g., a UL (uplink) dedicated physical control channel (DPCCH), for transmitting the preamble. Such a preamble would reduce the accuracy requirement for the initial power setting after a transmission gap and also help the channel estimation and the synchronization of a data channel, e.g., an enhanced dedicated channel (E-DCH). The preamble length can be optimized and defined using a predetermined criterion depending on: a) a degree of fading of a multipath channel which is used for transmitting data on the data channel and/or b) a throughput relative to a nominal throughput in the data channel.