N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 9 - Wireless Systems and Technologies                                                                                 Slide 42 of 80                                                                                                    ________________

    LMDS Spectrum

                                    LMDS Band - U.S.

                                    LMDS Band - Canada

                                    LMDS Band - Europe

                                    LMDS Spectral Capacity

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LMDS is a fixed broadband line-of-site, point-to-multipoint, microwave system which operates at high frequency, typically within specified bands in the 24 G Hz to 40 G Hz range.

LMDS Bands:    U.S.        - 1.3 G Hz bands at 28 and 31 G Hz
                     Canada    - 1 G Hz bands at 28 G Hz
                     Europe     - 2 G Hz bands at 40 G Hz
                     Asia         - Most countries in Asia do not have established policies for LMDS 

LMDS provides a line-of-site radio links over distances up to 6 Kms.
                    28 G Hz hop length    - 4 - 6 Kms
                    38 G Hz hop length    - 3 Kms

LMDS Spectral Capacity: For Example: 1G Hz band at 28 G Hz
Modulation Scheme    - 1.5 bits per sec (using 4-QAM modulation scheme)
LMDS Systems Raw Capacity:    1.5 G bps

Modulation Scheme    - 5 bits per sec (using 5-QAM modulation scheme)
LMDS Systems Raw Capacity:    5 G bps

The system capacity is more than adequate to distribute signals, which may consist of simultaneous voice, data, video, audio and the Internet traffic.