Carrier Interferometry Signal Segmentation for Wireless Capacity
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Solution Overview
Problem
Existing wireless communication systems, particularly DS-CDMA, face challenges with inter-symbol interference, near-far interference, high signal-processing effort, and limited effectiveness of beam forming due to their wideband nature, which hinders performance in multipath environments and ad-hoc networks.
Innovation Solution
The application of Carrier Interferometry (CI) in ad-hoc networking enhances bandwidth efficiency, reduces power consumption, and improves throughput by converting wideband signals into orthogonal narrowband components, enabling better interference cancellation and array processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DS-CDMA is used for wireless communication, then system capacity is improved through interference cancellation, but signal-processing effort increases proportionally to the cube of the bandwidth
Solution Approach 1:
The patent segments the wideband DS-CDMA signal into multiple narrowband components using Carrier Interferometry. Each narrowband component can be processed independently with reduced computational complexity, while maintaining the overall system capacity through coherent combination of the segmented signals.
2Productivity
If DS-CDMA uses wideband signals, then processing gain is increased, but beam forming effectiveness is reduced due to wideband nature
Solution Approach 1:
The patent divides the wideband signal into multiple narrowband frequency components using CI. Each narrowband component maintains coherent phase relationships that enable effective beam forming and spatial processing, while the overall processing gain is preserved through the combined effect of all narrowband components.
Solution Approach 2:
The patent transforms the signal from wideband to narrowband by changing the frequency domain parameters. This parameter transformation allows narrowband signal processing techniques including beam forming to be applied effectively, while the processing gain is maintained through the mathematical relationships established by Carrier Interferometry.
3Productivity
If DS-CDMA is used in multipath environment, then frequency-selective fade occurs, but inter-symbol interference increases when data bit duration is smaller than multipath delay
Solution Approach 1:
The patent segments the affected wideband signal into multiple narrowband components using Carrier Interferometry. Each narrowband component experiences less severe frequency-selective fading and reduced inter-symbol interference, allowing higher data transmission rates while maintaining signal integrity through coherent combination of the segmented narrowband signals.
Data Source
AI summary
Applications of CI processing to ad-hoc and peer-to-peer networking significantly improve throughput, network capacity, range, power efficiency, and spectral efficiency. CI-based subscriber units perform network-control functions to optimize network performance relative to channel conditions, network loads, and subscriber services. CI codes are used to identify and address network transmissions. Channel characteristics of communication links are employed to encode, address, and authenticate network transmissions. CI transceivers used as relays and routers employ unique characteristics of transmission paths to code and decode network transmissions. A central processor is adapted to perform array processing with signals received from, and transmitted by, a plurality of subscriber units in a wireless network.