Cross-Gray Coded Space-Time Matrix for MIMO Interference
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Solution Overview
Problem
In wireless communication systems, MIMO technology faces challenges with channel-channel interference, leading to reduced reliability, especially for high-speed data transmission, as it requires accurate channel state information, which is difficult to guarantee.
Innovation Solution
A method using cross-Gray coding, constellation diagram rotation, and space-time matrix generation to encode and transmit data bits without needing channel state information, employing differential spatial modulation and sphere decoding detection algorithms to enhance reliability and spectrum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MIMO technology is used to achieve high diversity gain and multiplexing gain, then data transmission speed is improved, but channel-channel interference increases and reliability drops
Solution Approach 1:
The invention segments the data transmission process into two distinct parts: spatial information transmission (which antenna is active) and data information transmission (modulated symbols). This segmentation allows the receiver to separately process spatial bits and data bits, reducing the interference between multiple transmitted signals while maintaining high data rates through parallel processing of both information types.
Solution Approach 2:
The invention extracts spatial information from the traditional MIMO data stream by designating specific bits as spatial bits that control antenna selection, while the remaining bits carry data information. This extraction separates the channel state dependency from the data transmission, allowing reliable spatial detection even in high-speed channels where channel estimation is difficult.
2Reliability
If SM technology is used to avoid channel-channel interference by activating only one transmitting antenna, then reliability is improved, but spectrum efficiency is reduced
Solution Approach 1:
The invention merges Spatial Modulation with MIMO by combining spatial bits (controlling antenna selection) and data bits (modulated symbols) into a unified transmission framework. Multiple antennas are activated simultaneously, each transmitting a composite signal containing both spatial and data information, thereby achieving both the reliability of SM and the spectrum efficiency of MIMO.
Solution Approach 2:
The invention adds a spatial dimension to the traditional data modulation by embedding spatial information in the bit structure itself. Each transmitted symbol carries dual information: spatial bits indicating which antenna is active and data bits carrying the actual message. This dimensional expansion allows the system to achieve higher spectrum efficiency while maintaining the interference-avoidance benefits of spatial modulation.
3Measurement precision
If channel state information is required for SM reception, then accurate detection is possible, but channel estimation difficulty increases especially for high-speed data flow
Solution Approach 1:
The invention enables the system to be self-sufficient by embedding all necessary information (both spatial and data information) directly in the transmitted signal without requiring external channel state information. The receiver can detect spatial bits and data bits independently using only the received signal and known modulation schemes, eliminating the need for complex channel estimation procedures even in high-speed fading channels.
Data Source
AI summary
The present application discloses a method for operating a wireless communication system. The method includes receiving a series of input data bits in a current timeslot by a transmitter and encoding the input data bits with a cross-Gray coding scheme to obtain coded information bits. Additionally, the method includes mapping the coded information bits to obtain respective multiple transmission symbols Xt for the current timeslot in a constellation diagram. Furthermore, the method includes converting the multiple transmission symbols Xt to generate a space-time matrix St of the current timeslot by incorporating spatial bits associated with orders of respective transmitting antennas based on a space-time matrix St-1 of a previous timeslot. Moreover, the method includes transmitting a respective one of elements in the space-time matrix St using a respective one transmitting antenna activated in the transmitter.