UMTS Control Data Source-Coding for Signaling Overhead Reduction
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Solution Overview
Problem
Current methods for transmitting control data in cellular networks, particularly in uplink signaling, face inefficiencies due to inadequate error protection and excessive signaling overhead, especially in soft handover scenarios where a 1-bit packet number is insufficient, leading to incorrect packet superimposition and reduced system performance.
Innovation Solution
The method involves source-coding the packet number together with other control parameters, such as the channel number and redundancy version, to optimize the available code word space, allowing for more efficient error protection and reduced signaling overhead by utilizing the code space more effectively, particularly by assigning different numbers of packet numbers and redundancy versions to different time channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a 1-bit packet number is used for control data transmission, then signaling overhead is reduced, but error protection becomes insufficient leading to incorrect packet superimposition
Solution Approach 1:
The patent combines the packet number with other control parameters (such as channel number, redundancy version, or time channel identifier) into a single source-coded control word. This merging allows the packet number to be transmitted without dedicated separate bits, reducing signaling overhead while maintaining error protection through the combined coding scheme.
Solution Approach 2:
The control parameters that are source-coded together with the packet number serve multiple functions: they control the HARQ process, identify the packet, and provide error detection capabilities. This multi-functionality allows the same coded words to achieve both packet identification and error protection without requiring additional dedicated signaling bits.
2Measurement precision
If more packet numbers are assigned to time channels, then packet identification accuracy improves, but code word space utilization becomes inefficient
Solution Approach 1:
The patent changes the parameter of packet number assignment from a fixed allocation to a dynamic assignment based on the specific time channel and transmission conditions. Different time channels can have different numbers of packet numbers assigned to them, optimized according to their respective error rates, traffic patterns, and handover probabilities, thereby improving identification accuracy where needed while conserving code word space elsewhere.
3Ease of manufacture
If separate source-coding is used for packet number and control parameters, then coding simplicity is maintained, but code space utilization becomes inefficient
Solution Approach 1:
The patent merges the source-coding of packet numbers with the source-coding of control parameters into a unified coding process. Instead of separately encoding packet numbers and then control parameters, the system performs joint source-coding that optimizes the use of available code words, thereby improving code space utilization while maintaining implementation feasibility through standardized coding procedures.
Data Source
AI summary
Apparatuses and methods for transmitting control data on a physical channel between a mobile radio device and a base station in a cellular network. In particular, in a mobile radio network according to the UMTS standard (UMTS=Universal Mobile Telecommunication System) a packet-oriented data transmission between the mobile radio device and the base station is controlled using control data, wherein the control data includes a packet number for identifying a data packet.