A SAW-based commutation signaling modem for broadband indoor wireless communication

Area of Science:

• Electrical Engineering
• Signal Processing
• Wireless Communications

Background:

• Commutation signaling offers bandwidth expansion and robustness against multipath interference in wireless digital communications.
• Exploiting time diversity through multipath diversity combining is crucial for reliable wireless signal transmission.

Purpose of the Study:

• To detail a surface acoustic wave (SAW) implementation of a commutation signaling modem for broadband indoor wireless communication.
• To demonstrate a low-cost, low-complexity differential coherent detector for commutation signaling modems.

Main Methods:

• The modem utilizes differential encoding and direct sequence spread spectrum modulation.
• A commutation signaling differential coherent detector was implemented using SAW and RF integrated circuit (RF IC) technologies.
• SAW devices were fabricated on 1280-rotated Y-cut, X-propagating lithium niobate with 1-micron line widths.

Main Results:

• The implemented modem supports a data rate of 40 Mb/sec, a chip rate of 200 MHz, and an IF frequency of 1 GHz.
• The differential coherent detector, a key component, was successfully realized using SAW and RF IC technologies.
• High-speed bilinear multipliers and low-impedance buffers were integrated using RF IC technology.

Conclusions:

• The developed SAW-based commutation signaling modem offers a robust and efficient solution for broadband indoor wireless communication.
• The integration of SAW and RF IC technologies enables the creation of low-cost, high-performance communication systems.
• This work validates the effectiveness of commutation signaling with differential coherent detection for overcoming wireless channel impairments.