N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 9 - Wireless Systems and Technologies                                                                                 Slide 46 of 80                                                                                                    ________________

    LMDS Network Capacity

LMDS Network Architecture:    A metropolitan area with 4 sectors.

Cellular Network Capacity

                                   Spectrum Bandwidth             - 2 G Hz
                                    Spectrum re-use                  - 4
                                    Usable spectrum per sector    - 500 M Hz
                                    Symmetrical upstream and
                                    downstream                         - 250 M Hz in each direction
                                                Each customer link    - o.5 M Hz
                                                Customer per sector  - 500
                                                Spectral efficiency    - 4 b/s/Hz
                                                Sector capacity        - 250 M Hz x 4 b/s/Hz = 1000 M bps
                                                Capacity per cell       - 4 x 1000 M bps = 4 G bps in each direction
                                    Average duplex user bit rate    - 2 M bps

LMDS network capacity    - 4 x 500 = 2000 users (mix of residential and business users)

A typical LMDS cell structure with a frequency reuse factor 4 and 4 sector hub antenna.

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