Implicit MCS Signaling for LTE Control Channel Overhead Reduction
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Solution Overview
Problem
Current wireless communication systems in LTE face inefficiencies due to the need for double signaling overhead when transmitting multiple codewords, as each control channel codeword must independently signal modulation and coding rate information for shared channel codewords, leading to increased bandwidth usage.
Innovation Solution
Implementing a pre-defined mapping rule to implicitly indicate the modulation and coding rate of a second shared channel codeword within the bit sequence of a first control channel codeword, reducing the need for explicit signaling in the second control channel codeword and minimizing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If explicit signaling is used for each control channel codeword to indicate modulation and coding rate, then complete transmission format information is provided to the UE, but control channel overhead increases significantly
Solution Approach 1:
The patent merges the signaling of MCS for multiple shared channel codewords into a single control channel codeword. Instead of transmitting separate MCS indications in each control channel codeword, the invention combines them into one unified signaling structure, thereby reducing the total number of bits required while maintaining complete transmission format information.
Solution Approach 2:
The single control channel codeword is designed to serve multiple functions simultaneously: it signals the MCS for the first shared channel codeword explicitly, and through a predetermined mapping rule, it also implies the MCS for the second shared channel codeword. This multi-functionality allows one signaling structure to convey information for multiple codewords.
2Quantity of substance
If implicit indication through mapping rules is used, then control channel overhead is reduced, but the system requires pre-defined mapping rules stored at both transmitter and receiver
Solution Approach 1:
The mapping rules are predetermined and pre-stored in both the transmitter and receiver before actual data transmission begins. This preliminary preparation eliminates the need for dynamic rule negotiation during transmission, reducing real-time processing complexity while enabling efficient implicit signaling.
Data Source
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AI summary
A first parameter such as an indicator of modulation and coding scheme MCS for a first shared channel SCH codeword and a second parameter for a second SCH codeword are determined. From a locally stored mapping rule a bit sequence that explicitly indicates the first parameter and that implicitly indicates the second parameter is chosen, and a first control channel CCH codeword is transmitted with the explicit bit sequence that explicitly indicates the first parameter for the first SCH codeword and a second CCH codeword is sent companion to the first CCH codeword, wherein the second parameter for the second SCH codeword is implicitly indicated by the explicit bit sequence of the first CCH codeword. The receiving party determines the second parameter by its own locally stored mapping rule, and an indicator in each CCH codeword may be used to inform the receiver that the two (or more) CCH codewords are associated with one another and to use its mapping rule to determine the second parameter.