MIMO Single-Antenna Signal Separation via Orthogonal Code Multiplexing
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Solution Overview
Problem
MIMO communication systems face challenges in compact mobile terminals due to the need for multiple antennas and circuits, which increases size, weight, and power consumption, and struggles with signal separation caused by correlation between receive and transmit antennas, limiting the effectiveness of MIMO performance.
Innovation Solution
A MIMO communication method that uses multiplexing of codes with different amplitudes for OFDM, allowing a single receive antenna to achieve high-speed communication by processing signals with orthogonal codes and coefficients, reducing the number of required receive antennas and enhancing signal separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple receive antennas and receive circuits are incorporated to achieve N×N MIMO reception, then MIMO communication capacity and speed are improved, but device size, weight, and power consumption increase
Solution Approach 1:
The patent merges multiple receive antennas into a single receive antenna by using code division multiplexing. Different transmit antennas transmit signals multiplied by different orthogonal codes, and the single receive antenna receives all signals simultaneously. The receiver separates the signals by correlating with the respective orthogonal codes, achieving N×N MIMO reception with only one receive antenna, thus eliminating the need for multiple receive circuits and reducing device weight.
Solution Approach 2:
The single receive antenna performs multiple functions: it receives signals from all N transmit antennas simultaneously and, through code correlation, separates and decodes signals from each transmit antenna. This multi-functional approach replaces the need for N dedicated receive antennas and circuits, significantly reducing device complexity and weight while maintaining full MIMO capacity.
2Reliability
If multiple receive antennas are used for N×N MIMO reception, then signal separation capability is improved, but the number of components and device complexity increase
Solution Approach 1:
The patent combines N receive antennas into one by using orthogonal codes for signal separation. The single receive antenna captures signals from all transmit antennas, and the receiver uses code correlation to separate them, reducing component count from N receive antennas to just one while maintaining signal separation capability.
Solution Approach 2:
The patent changes the separation parameter from spatial domain (multiple physical antennas) to code domain (orthogonal codes). By multiplying transmit signals with different orthogonal codes and correlating received signals with these codes, the system achieves signal separation without needing multiple physical receive antennas, thus reducing device complexity.
3Reliability
If diversity reception with multiple antennas is implemented, then reception reliability is improved, but the number of antennas required increases to (2×N) or more
Solution Approach 1:
The patent merges diversity reception functionality into a single antenna system by using orthogonal codes. Instead of requiring 2×N antennas for diversity, the system uses one receive antenna with code-based signal separation, achieving both MIMO capacity and diversity gain with minimal hardware.
Solution Approach 2:
The patent introduces orthogonal codes as an intermediary mechanism to achieve diversity reception. The codes act as a mediator that enables the single receive antenna to distinguish and separately process signals from multiple transmit antennas, providing diversity gain without requiring multiple physical antennas.
4Volume of moving object
If a single receive antenna is used to reduce device size, then compactness is improved, but signal separation becomes difficult due to correlation between receive and transmit antennas
Solution Approach 1:
The patent changes the signal separation parameter from spatial domain to code domain. By multiplying transmit signals with different orthogonal codes and correlating the received signal with these codes, the system achieves effective signal separation even with a single receive antenna, overcoming the correlation problem without compromising compactness.
Data Source
AI summary
A first digital signal sequence including I and Q digital signal sequences is obtained, the first digital signal sequence being obtained by multiplying each bit of an I-sequence and a Q-sequence in a digital signal sequence system by a first code among codes constituting n-th order (n is an integer) orthogonal codes. A second digital signal sequence is obtained by multiplying I and Q digital signal sequences by a first coefficient greater than 1, the I and Q digital signal sequences being obtained by multiplying each of the bits in the I-sequence and the Q-sequence in the digital signal sequence system by a first code among codes constituting 2n-th order orthogonal codes. The first digital signal sequence and the second digital signal sequence are added on a bit-by-bit basis to create one digital signal sequence, and the one digital signal sequence is transmitted from a single antenna.