NEC Introduces Broadband Wireless System, CDMA BTS System

NEC America has developed a point-to-multipoint broadband access system for Local Multipoint Distribution Service (LMDS) applications.

The new broadband system spans the 27 to 28.35 GHz and 31 to 31.3 GHz frequency ranges. In the downstream of its base station modem, this system offers a quadrature phase-shift keying (QPSK) modulation technique, a 30-Mb/s transmission rate, a 15 Mbaud symbol rate, and 21 MHz channel separation. In the upstream of the base station modem, the broadband access system features a differential QPSK (DQPSK) modulation technique, a 4-Mb/s transmission rate, a 2 Mbaud symbol rate, and 3.5 MHz channel separation.

NEC's new LMDS system is targeted at residential and business applications. In residential applications, this system can deliver high-speed Internet access, telephony, TV broadcast, and video on demand. In business settings, the system can provide videoconferencing, local-area network (LAN) interconnect, private networking, wireless trunking/backhaul, and fiber backup.

NEC has also released a new base station transceiver system (BTS) for CDMA cellular systems at PCS '98. Developed by NEC do Brasil, the Outdoor Mini BTS is designed for low- and medium-traffic areas, such as stadiums, shopping centers, highways, and tunnels.

This BTS combines an air conditioner, battery, and transmission equipment in a single unit that measures 960 x 700 x 1500 mm and weighs approximately 350 kg. The BTS' transmitter operates across the 869.04 to 893.97 MHz band and features +/- 0.05 frequency tolerance, 10 W maximum output power, a 1.2288 Mchips/s modulation rate, approximately +/-3 µs pilot time tolerance, better than +/-50 ns code channel time tolerance, and less than -27 dB code domain power. The product's receiver, on the other hand, works across the 824.04 to 848.97 MHz range and sports +/-0.05 frequency tolerance, less than -80 dBm conducted spurious emissions, and 50 W nominal impedance.