Considerations of modem design for LMDS systems
نویسنده
چکیده
During the last 2-3 years, there has been a lot of activities aiming to deploy broadband wireless access systems. The US LMDS auctions in February-March 1998 of 1.3 GHz of spectrum between 27.5 GHz and 31.3 GHz triggered e orts to develop system solutions and standards that have as objective to render LMDS systems competitive to other broadband, and primarily wireline, technologies. The modem design must be matched to the channel characteristics of LMDS systems, which are very di erent from those of coax and even lower frequency wireless communications systems. In addition, the cost factor is a key issue to face the competition from other technologies. A modem design meeting these two constraints is described in this paper, together with an analysis of the main impairements characterizing the LMDS channel. The modem includes fully rotational invariant TCM, amplitude phase modulation (APM), equalization and linearization.
منابع مشابه
Coding and Modulation for LMDS and Analysis of the LMDS Channel
Local Multipoint Distribution Service (LMDS) has the potential to become a viable alternative to coaxial cable, fiber and other wired and wireless technologies providing "last mile" communication services. A major obstacle, however, is the high equipment cost. While for example cable modems supporting two-way services are available for $200 to $300, LMDS modem providing similar services will co...
متن کاملAn Adaptive Multimode Modulation Modem for Point to Multipoint Broadband Radio
Future broadband fixed wireless access systems for Local Multipoint Distribution Services (LMDS) will use an adaptive multimode modulation in order to provide high data rates with high reliability and high spectral efficiency. The new complex physical layer requires new concepts to meet the requirements of high performance and at the same time to reduce the hardware effort to a reasonable size....
متن کاملBehavioral Considerations in Developing Web Information Systems: User-centered Design Agenda
The current paper explores designing a web information retrieval system regarding the searching behavior of users in real and everyday life. Designing an information system that is closely linked to human behavior is equally important for providers and the end users. From an Information Science point of view, four approaches in designing information retrieval systems were identified as system-...
متن کاملPower Amplifier Linearization for Lmds from High Altitude Aeronautical Platforms
Introduction. Broadband LMDS (Local Multi-Point Distribution Systems) is a wireless point-to-multipoint communication system operating above 20GHz (usually around 26− 31GHz) that can be used to provide digital voice, data, Internet, and video services. One possible solution for LMDS is to use High-Altitude Aeronautical Platforms (HAAPs), which are situated in the stratosphere, 20− 22km above th...
متن کاملLocal Multipoint Distribution Service (LMDS)
This is a survey paper on LMDS. With a introduction on LMDS and then a discussion on fixed wireless networks, this paper looks into different ways fixed wireless communication can be achieved and then gives a brief description on the various broadbands available for communication. It also discusses technical and design issues involved with LMDS. See also: Other Reports on Recent Advances in Net...
متن کامل