Orthogonal Stream Spatial Multiplexing for MIMO Data Capacity
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Solution Overview
Problem
Current wireless communication networks, even with advanced 5G technology, face limitations in data transfer capacity, as they struggle to meet the growing demand for mobile and remote data access, with MIMO techniques only being able to guarantee a 2× data transfer at best and delivering a maximum of 4× under special circumstances.
Innovation Solution
The implementation of orthogonal stream spatial multiplexing (OSSM) technology, which splits and encodes data streams into multiple spatial streams with unique orthogonal time-varying polarizations, allowing for the transmission of an arbitrarily large number of streams on the same frequency channel, effectively multiplying data transfer capacity by multiplying the number of streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional MIMO spatial multiplexing is used, then data transfer capacity is improved (up to 4×), but the number of transmissible streams is limited and requires complex hardware modifications
Solution Approach 1:
The patent segments the data stream into multiple spatial streams (n streams) that can be transmitted simultaneously on the same frequency channel. Each spatial stream is separated by orthogonal polarization codes, allowing independent transmission and reception. This segmentation enables arbitrary n× data transfer capacity multiplication without requiring complex hardware changes, as the segmentation is achieved through signal processing rather than physical layer modifications.
Solution Approach 2:
The patent introduces polarization diversity as an additional dimension for multiplexing. Instead of using conventional spatial multiplexing that relies on multiple antennas with fixed polarizations, the invention time-varyingly modulates the polarization state of each spatial stream using orthogonal polarization codes. This adds a temporal-polarization dimension to the transmission, enabling n streams to be distinguished by their unique polarization trajectories rather than requiring n×n physical antennas.
2Productivity
If the number of spatial streams is increased to multiply data transfer capacity, then productivity improves, but interference between streams increases
Solution Approach 1:
The patent uses orthogonal polarization codes as an intermediary mechanism to separate multiple spatial streams. Each spatial stream is modulated with a unique polarization code that is orthogonal to the codes of other streams. This intermediary polarization coding allows the receiver to distinguish between streams by matching the polarization characteristics, effectively eliminating inter-stream interference even when multiple streams occupy the same frequency channel and spatial resources.
Solution Approach 2:
The patent dynamically changes the polarization parameter of each spatial stream over time according to its assigned orthogonal polarization code. By time-varying the polarization state in a structured manner, the system creates orthogonal signal spaces that are mutually distinguishable. This parameter modulation allows arbitrary numbers of streams to be transmitted simultaneously without interference, as each stream's polarization trajectory is unique and orthogonal to others.
3Ease of operation
If existing MIMO hardware is used, then ease of operation is maintained, but data transfer capacity is limited to 2× or 4×
Solution Approach 1:
The patent makes the existing MIMO transceiver hardware universal by enabling it to perform multiple functions through software-based polarization coding. The same physical hardware that traditionally supports fixed polarization MIMO operations can now be configured to support time-varying polarization multiplexing of arbitrary order n. This universality is achieved by implementing the polarization code modulation and de-modulation in the signal processing domain, allowing existing antennas and receivers to handle multiple spatial streams without requiring dedicated hardware for each stream.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
OSSM significantly increases data transfer capacity by enabling the transmission of multiple streams with identical amplitude and modulation on the same frequency, achieving data transfer rates up to n times that of a single stream, without requiring costly modifications to existing MIMO transceiver hardware.
Implementation Method 1
Each of the n spatial streams is modulated with a unique time-varying polarization code, thereby toggling the instantaneous polarization of each spatial stream in a mutually orthogonal time varying manner
Implementation Method 2
The n resulting OSSM spatial streams are then launched wirelessly to the desired destination. The n radiated OSSM spatial streams impinge upon n corresponding Rx OSSM Apparatus that actually perform the receive-side orthogonal stream spatial de-multiplexing
Data Source
AI summary
Methods and apparatus for orthogonal stream spatial multiplexing. In one embodiment, a method includes splitting and modulating a data stream into n MIMO RF spatial streams and coupling them to corresponding switchable polarization antenna elements controlled via orthogonal binary codes for transmission. Each transmitted stream manifests as time-varying-polarization-orthogonal to the other n−1 spatial streams. The method includes reception of the streams at their destination using corresponding antenna elements controlled by the same set of orthogonal codes. Thus, each of the n transmitted spatial streams is polarization-match-filtered, unambiguously separated and individually recovered from all the others upon reception for subsequent demodulation and MIMO spatial recombination into the original data stream. Thus, n MIMO spatial streams emanating from a common source and featuring equal amplitude and bandwidth but bearing distinct data and exhibiting mutually orthogonal time varying polarization will propagate mutually interference-free on the same frequency channel to a single destination.