IF Modem Segmentation for High Data Rate Wireless Fronthaul
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Solution Overview
Problem
Conventional modem architectures for high data rate wireless communications are costly due to the need for expensive analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) for wideband signals, and face challenges with multipath effects and signal distortions, especially in the 60 GHz domain, which limits channel bandwidth and requires high signal-to-noise ratios.
Innovation Solution
The solution employs a double conversion architecture using multiple intermediate frequency (IF) modems with a two-channel modulator, demodulator, and transceiver, where each IF modem operates at a different frequency, synthesizing a wideband signal without the need for expensive broadband converters, and utilizes a transformation module to synchronize oscillators and compensate for phase noise, allowing for flexible data rate transmission and operation in the 60 GHz ISM band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional modem architectures use high speed analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) for wideband signals, then data rates above 5 Gbit/s can be achieved, but the cost becomes very high
Solution Approach 1:
The patent divides the wideband signal processing into multiple narrowband IF modem channels, each handling a specific frequency range. Instead of using a single expensive broadband ADC/DAC, the system segments the frequency spectrum and processes each segment separately with lower-cost narrowband converters, thereby achieving high data rates while reducing component costs
Solution Approach 2:
The patent introduces intermediate frequency (IF) modems as intermediary components between the baseband processing and the RF front end. These IF modems act as mediators that convert baseband signals to intermediate frequencies, enabling the use of lower-cost narrowband ADCs/DACs while still supporting wideband communication through multiple frequency channels
2Adaptability or versatility
If channel bandwidth is limited to 2 GHz or 2.5 GHz in the 60 GHz domain, then regulatory requirements are met, but high signal-to-noise ratio is required which increases system complexity
Solution Approach 1:
The patent segments the limited 2-2.5 GHz channel bandwidth into multiple narrower sub-channels, each handled by a separate IF modem. This segmentation allows the system to meet regulatory bandwidth limits while using multiple parallel channels to achieve high aggregate data rates with more relaxed SNR requirements per channel
3Productivity
If multiple frequencies are served to increase data rate, then data rates beyond 5 Gbit/s are achieved, but the need for expensive broadband converters increases
Solution Approach 1:
The patent segments multiple frequency channels into separate IF modem processing paths, allowing each path to use narrowband converters optimized for specific frequency ranges. This approach enables serving multiple frequencies for high data rates while avoiding the need for expensive broadband converters that would be required to handle all frequencies simultaneously
Solution Approach 2:
The patent designs the IF modem architecture to be universally applicable across multiple frequency channels. Each IF modem can be configured to handle different frequency ranges, allowing the same hardware design to serve multiple frequencies through reconfiguration, thereby reducing the need for expensive dedicated broadband converters for each frequency
Data Source
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AI summary
An apparatus for high data rate communication comprises at least a signal de-multiplexer and a signal multiplexer whereas the signal de-multiplexer and the signal multiplexer are connected to a modem unit via signal lines, a reference control unit and an antenna. The invention relates also to a method for providing intermediate frequency (IF) modems of a modem unit with a high data rate signal, whereas the high data rate signal is modulated by the IF modem that is controlled by a clock rate, each IF modem generates one band limited signal at some IF frequency. The object of the invention is to replace expensive converters with simple means and at low cost in order to provide a flexible solution for wireless fronthaul that allows a bidirectional wireless transmission of wideband signals, e.g. 10 Gbps digital IQ data. This is solved by using a plurality of intermediate frequency (IF) modems that generate a wide band signal by combining the individual spectra generated by each IF modem.