MIMO Signal Stream Resizing for Multi-Antenna Base Stations
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Solution Overview
Problem
Current MIMO techniques, such as space-time coding (STC) and spatial multiplexing (SM), are ineffective in wireless communications networks with base transceiver stations (BTS) having more than two antennas, leading to complex signal acquisition and reduced network performance due to the need for extra channel resources and upgraded mobile stations.
Innovation Solution
The method involves dividing antennas into logical groups to create multiple MIMO signal streams using cyclic delay and power amplifier modules, allowing for improved frequency diversity without requiring mobile station upgrades, by employing STC or SM methods developed for 2-antenna BTS systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If STC or SM methods are employed in a wireless communications network with a BTS having more than two antennas, then the network can support more antennas, but it requires reserving extra channel resources for non-overlapping pilot signals for each antenna, which consumes a lot of radio bandwidth and reduces network utilization
Solution Approach 1:
The patent combines multiple antenna signals into a reduced number of signal streams. Specifically, it uses signal processing techniques to merge the signals from N antennas into 2 or fewer MIMO signal streams, thereby reducing the need for separate pilot signals for each antenna and conserving radio bandwidth while still utilizing multiple antennas for improved performance
Solution Approach 2:
The patent changes the parameter of signal stream dimensionality by transforming N-dimensional antenna signals into 2-dimensional MIMO signal streams through mathematical transformations and signal processing, allowing the system to maintain compatibility with existing 2-antenna MIMO processing while utilizing more physical antennas
2Productivity
If a BTS is upgraded to have more than two antennas, then additional signals can be transmitted, but the mobile station must also be upgraded to process MIMO signals from more than two antennas, increasing system complexity
Solution Approach 1:
The patent merges multiple antenna inputs into a reduced set of 2 or fewer MIMO signal streams that can be processed by existing mobile stations with standard 2-antenna MIMO capability, eliminating the need for mobile station upgrades while still benefiting from multiple transmitting antennas at the BTS
Solution Approach 2:
The patent creates a universal interface that allows BTS with any number of antennas to communicate with mobile stations having fixed 2-antenna MIMO processing capability. The signal processing transformation makes the system universal, where the BTS can have N antennas but the interface to mobile stations remains standardized at 2 streams
3Productivity
If signals are transmitted from an antenna array of more than two antennas, then more signal streams can be created, but detecting these signals becomes more complicated, making the signal acquisition process complex
Solution Approach 1:
The patent combines N antenna signals into 2 or fewer MIMO signal streams using signal processing techniques, thereby reducing the detection complexity to levels handled by standard 2-antenna MIMO receivers while preserving the benefits of multiple transmitting antennas through constructive signal combining
Data Source
AI summary
The present invention discloses a method for generating a signal stream in a multiple-input-multiple-output (MIMO) channel of a wireless communications system. The method comprises encoding at least one transmitting message into a first signal sequence, transforming the first signal sequence into a second and a third signal sequence by a first and a second predetermined rule, respectively, coupling the second signal sequence to a first antenna, coupling the third signal sequence to a second antenna, transmitting a signal stream comprising the first and second signal sequences to a mobile station.