Microwave Backhaul Bandwidth Efficiency via Orbital Angular Momentum Multiplexing
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Solution Overview
Problem
Microwave and satellite backhaul connections in wireless telecommunication systems are bandwidth limited due to the number of available radio frequencies, limiting the capacity for information transmission without interfering with existing signals.
Innovation Solution
The system employs signal processing circuitry to impart different orbital angular momentums to multiple data streams, allowing them to be transmitted on the same frequency, increasing bandwidth efficiency by using an antenna with a spiral phase plate to generate unique orbital angular momentums for each data stream, enabling multiple signals to be transmitted without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple data streams are transmitted on the same frequency, then bandwidth efficiency is improved, but signal interference occurs
Solution Approach 1:
The patent applies orbital angular momentum (OAM) to encode data streams, adding a new dimensional parameter to the electromagnetic wave beyond traditional frequency and amplitude. By modulating the OAM mode index of the carrier wave, multiple independent data streams can be transmitted on the same frequency without interference, as each stream is distinguished by its unique OAM state. This dimensional extension resolves the contradiction by enabling frequency reuse while maintaining signal separation.
Solution Approach 2:
The invention changes the physical parameter of the electromagnetic wave from conventional amplitude/frequency modulation to orbital angular momentum mode modulation. By varying the OAM mode index (l=0, ±1, ±2, ...) of the carrier wave, the system encodes multiple data streams with distinct parameter values. This parameter transformation allows simultaneous transmission of multiple streams on the same frequency, improving bandwidth efficiency while preventing signal interference through orthogonal OAM states.
2Productivity
If additional frequencies are allocated to increase capacity, then system capacity is improved, but bandwidth availability is reduced
Solution Approach 1:
Instead of allocating additional frequency resources, the patent exploits the orbital angular momentum dimension of electromagnetic waves. By modulating different OAM mode indices on the same carrier frequency, the system achieves multiplexing without consuming additional spectral bandwidth. This approach increases system capacity while preserving bandwidth availability, as the OAM dimension provides virtually unlimited orthogonal channels within the existing frequency spectrum.
Solution Approach 2:
The invention makes a single frequency resource serve multiple functions by enabling simultaneous transmission of multiple data streams through OAM modulation. The same frequency carrier can carry multiple independent data streams distinguished by their OAM states, making the frequency resource universal and multi-functional. This eliminates the need to allocate separate frequencies for different data streams, thereby increasing system capacity without reducing bandwidth availability.
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
This approach effectively increases the bandwidth capacity of microwave backhaul connections by allowing multiple data streams with different orbital angular momentums to be transmitted on a single frequency, enhancing the system's capacity without requiring additional frequencies.
Implementation Method 1
Each of the plurality of input data streams on the at least one frequency have a different orbital angular momentum imparted thereto
Data Source
AI summary
An apparatus for transmitting information in a wireless communication system includes a first interface for receiving a plurality of input data streams. Signal processing circuitry transmits and receives the plurality of input data streams on at least one frequency. Each of the plurality of input data streams on the at least one frequency have a different orbital angular momentum imparted thereto.