Alamouti Matrix Pre-coding for MIMO Antenna Power Balance
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Solution Overview
Problem
Current IEEE 802.16e communication systems face limitations in capacity, access performance, and throughput due to deficiencies in power balanced space time codes for odd numbers of transmit antennas and insufficient redundancy support for users on different layers.
Innovation Solution
The method involves pre-coding information bits to generate transmit symbols, which are then encoded into Alamouti matrices and transmitted using multiple antennas over specific time intervals or frequencies, ensuring all information bits are represented across each antenna, and utilizing space time/frequency block codes to balance transmission power and redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional space time codes are used in IEEE 802.16e systems, then system capacity and throughput are limited, but implementing power balanced codes for odd numbers of transmit antennas increases code complexity
Solution Approach 1:
The patent divides the transmission system into multiple Alamouti matrices, each handling a subset of transmit antennas. For four antennas, two separate 2x2 Alamouti matrices are used, where each matrix operates on a pair of antennas independently. This segmentation allows the system to achieve full capacity with even numbers of antennas while maintaining manageable complexity through modular structure.
Solution Approach 2:
The patent creates a universal coding framework that can handle both even and odd numbers of transmit antennas using the same Alamouti matrix-based approach. The method generalizes the conventional Alamouti code to work with any number of antennas by systematically distributing symbols across multiple matrices, making the solution applicable to various antenna configurations without requiring separate code designs.
2Productivity
If conventional space time codes are used, then system throughput is limited, but supporting users on different layers with sufficient redundancy increases coding complexity
Solution Approach 1:
The patent segments the coding task by assigning different Alamouti matrices to different user layers. Each layer receives a dedicated matrix configuration, allowing independent optimization of redundancy and throughput for each user group. This segmentation enables sufficient redundancy for multi-layer users without increasing the complexity of individual code blocks.
Solution Approach 2:
The patent applies partial redundancy by providing sufficient protection only where needed. Users on different layers receive differentiated redundancy levels based on their requirements, rather than uniformly protecting all transmissions. This selective approach maintains throughput efficiency while ensuring adequate error protection for critical data streams.
3Stability of the object's composition
If all information bits are represented across each antenna, then power distribution becomes balanced, but this requires careful pre-coding and mapping of symbols
Solution Approach 1:
The patent performs preliminary pre-coding by systematically mapping information bits to transmit symbols before the actual transmission begins. The pre-coding process arranges bits into sets that will be distributed across different Alamouti matrices, ensuring that each antenna receives an equal share of power. This preliminary organization simplifies the subsequent transmission process while maintaining power balance.
Solution Approach 2:
The patent changes the parameter distribution by systematically varying the mapping of information bits to constellation points across different antennas and time intervals. By controlling the symbol generation and distribution parameters, the system achieves uniform power distribution across all transmit antennas without requiring complex real-time adjustments during transmission.
Data Source
AI summary
Methods and devices are provided for MIMO OFDM transmitter and receivers having odd and/even numbers of transmit antennas. Various methods for pre-coding information bits before space time coding (STC) are described for enabling transmission of information bits over all antennas. Methods of decoding received signals that have been pre-coded and STC coded are also provided by embodiments of the invention. Pilot patterns for downlink and uplink transmission between a base station and one or more wireless terminals for three transmit antenna transmitters are also provided. Variable rate codes are provided that combine various fixed rate codes in a manner that results in codes whose rates are dependent on all the various fixed rate codes that are combined.