Jang Dae Ig , Kim Nae Su

The KIPS Transactions:PartC, Vol. 11, No. 1, pp. 141-148, Feb. 2004
10.3745/KIPSTC.2004.11.1.141,   PDF Download:

Abstract

Recently, the demand of broadband communications such as high-speed internet, HDTV, 3D-HDTV, and ATM backbone network has been increased drastically. For transmitting the broad-bandwidth data using wireless network, it is needed to use ka-band frequency. However, the use of this ka-band frequency is seriously affected to the received data performance by rain fading and atmospheric propagation loss at the Ka-band satellite communication link. So, we need adaptive MODEM to endure the degraded performance by channel environment. In this paper, we will present the structure and design of the 155Mbps adaptive Modem adaptively compensated against channel environment. In order to compensate the rain attenuation over the ka-band wireless channel link, the adaptive coding schemes with variable coding rates and the multiple modulation schemes such as trellis coded 8-PSK, QPSK, and BPSK are adopted. And the blind demodulation scheme is proposed to demodulate without information of modulation mode at the multi-mode demodulator, and the fast phase ambiguity resolving scheme is proposed. The design and simulation results of adaptive Modem by SPW model are provided. This 155Mbps adaptive MODEM was designed and implemented by single ASIC chip with the 0.25㎛ CMOS standard cell technology and 950 thousand gates.

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