Alamouti Code MIMO CDM Orthogonality
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Solution Overview
Problem
In next-generation multimedia radio communication systems, maintaining orthogonality between multiple-input multiple-output (MIMO) and code division multiplexing (CDM) techniques is challenging, leading to reduced reliability and system performance due to inter-symbol interference and mobility-related issues.
Innovation Solution
The method involves generating symbols using an Alamouti code and transmitting them through multiple antennas with distinct resource indices, ensuring orthogonality by using different resource indices for each transmit symbol, thereby maintaining system reliability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MIMO and CDM techniques are combined to increase data transmission rate, then productivity is improved, but orthogonality is lost leading to reduced reliability
Solution Approach 1:
The transmission system is segmented into multiple independent resource indices (first resource index and second resource index) that are assigned to different transmit symbols. This segmentation allows each symbol to be transmitted through different resource allocations, maintaining orthogonality while enabling parallel transmission through multiple antennas, thus resolving the contradiction between increased data rate and maintained orthogonality.
Solution Approach 2:
The patent introduces resource indices as an additional dimension for resource allocation beyond the traditional spatial dimension. By assigning different resource indices to symbols transmitted through different antennas, the system creates a new dimension of orthogonality that allows MIMO and CDM to coexist without interference, enabling both high data transmission rates and reliable orthogonality maintenance.
2Productivity
If multiple transmit antennas are used to increase data rate, then productivity is improved, but inter-symbol interference increases due to mobility
Solution Approach 1:
The patent applies preliminary action by pre-assigning different resource indices to different transmit symbols before transmission. This preliminary resource allocation ensures that symbols transmitted through multiple antennas are already differentiated in the resource domain, preventing inter-symbol interference even under mobile conditions, while still enabling high data rates through parallel transmission.
Data Source
AI summary
A method of transmitting, by a transmitter, information in a wireless communication system, the method includes generating first and second symbols; generating first and second transmit vectors on the basis of an Alamouti code from the first and second symbols; and transmitting the first transmit vector through a first antenna and transmitting the second transmit vector through a second antenna. The first transmit vector consists of a first transmit symbol and a second transmit symbol. The second transmit vector consists of a third transmit symbol and a fourth transmit symbol. The first, second, third, and fourth transmit symbols are transmitted based on first and second resource indexes. The first symbol is a first modulation symbol for first information, and the second symbol is a second modulation symbol for second information.