What is the Local Multi-Point Distribution Service?

Hi guys,

Does anyone know about LMDS ?
I think it stands for Local multi-point Distriduted System

can anyone explain about it?

what is lmds in wireless access

amihomo,

See overview below from h**p://www.wcai.com/lmds.htm


LMDS Overview

LMDS is a broadband wireless point-to-multipoint communication system operating above 20 GHz (depending on country of licensing) that can be used to provide digital two-way voice, data, Internet, and video services (see Figure 1).
Figure 1. LMDS System

The acronym LMDS is derived from the following:

L (local)�denotes that propagation characteristics of signals in this frequency range limit the potential coverage area of a single cell site; ongoing field trials conducted in metropolitan centers place the range of an LMDS transmitter at up to 5 miles

M (multipoint)�indicates that signals are transmitted in a point-to-multipoint or broadcast method; the wireless return path, from subscriber to the base station, is a point-to-point transmission

D (distribution)�refers to the distribution of signals, which may consist of simultaneous voice, data, Internet, and video traffic

S (service)�implies the subscriber nature of the relationship between the operator and the customer; the services offered through an LMDS network are entirely dependent on the operator's choice of business

Why LMDS?
More recent advances in a point-to-multipoint technology offer service providers a method of providing high-capacity local access that is less capital-intensive than a wireline solution, faster to deploy than wireline, and able to offer a combination of applications.

Point-to-point fixed wireless networks have been commonly deployed to offer high-speed dedicated links between high-density nodes in a network. Moreover, since a large part of a wireless network's cost is not incurred until the customer premise equipment is installed, the network service operator can time capital expenditures to coincide with the signing of new customers. LMDS provides an effective last-mile solution for the incumbent service provider and can be used by competitive service providers to deliver services directly to end users. Benefits can be summarized as follows:

* lower entry and deployment costs
* ease and speed of deployment (systems can be deployed rapidly with minimal disruption to the community and the environment)
* fast realization of revenue (as a result of rapid deployment)
* demand-based buildout (scalable architecture employing open industry standards ensuring services and coverage areas can be easily expanded as customer demand warrants)
* cost shift from fixed to variable components (with traditional wireline systems, most of the capital investment is in the infrastructure, while with LMDS a greater percentage of the investment is shifted to customer-premise equipment [CPE], which means an operator spends dollars only when a revenue paying customer signs on)
* no stranded capital when customers churn
* cost-effective network maintenance, management, and operating costs

Network Architecture

Various network architectures are possible within LMDS system design. The majority of system operators will be using point-to-multipoint wireless access designs although point-to-point systems and TV distribution systems can be provided within the LMDS system. It is expected that the LMDS services will be a combination of voice, video, and data. Therefore, both asynchronous transfer mode (ATM) and Internet protocol (IP) transport methodologies are practical when viewed within the larger telecommunications infrastructure system of a nation.

The LMDS network architecture consists of primarily four parts: network operations center (NOC), fiber-based infrastructure, base station, and customer premise equipment. This tutorial primarily discusses base station, customer premise, and NOC designs.
System Equipment Segments

The NOC contains the network management system (NMS) equipment that manages large regions of the customer network. Multiple NOCs can be interconnected. The fiber-based infrastructure typically consists of synchronous optical network (SONET) optical carrier (OC)�12, OC�3, and DS�3 links; central-office (CO) equipment; ATM and IP switching systems; and interconnections with the Internet and public switched telephone networks (PSTN).
If local switching is present, customers connected to the base station can communicate with one another without entering the fiber infrastructure.

The base station is where the conversion from fibered infrastructure to wireless infrastructure occurs. Base station equipment includes the network interface for fiber termination; modulation and demodulation functions; and microwave transmission and reception equipment typically located atop a roof or a pole. Key functionalities which may not be present in different designs include local switching. This function implies that billing, channel access management, registration, and authentication occur locally within the base station.

The alternative base-station architecture simply provides connection to the fiber infrastructure. This forces all traffic to terminate in ATM switches or CO equipment somewhere in the fiber infrastructure. In this scenario, if two customers connected to the same base station wish to communicate with each other, they do so at a centralized location. Billing, authentication, registration, and traffic-management functions are performed centrally.

The customer-premise configurations vary widely from vendor to vendor. Primarily, all configurations will include outdoor mounted microwave equipment and indoor digital equipment providing modulation, demodulation, control, and customer-premise interface functionality. The CPE may attach to the network using time-division multiple access (TDMA), frequency-division multiple access (FDMA), or code-division multiple access (CDMA) methodologies. The customer premise interfaces will run the full range from digital signal, level 0 (DS0), plain old telephone service (POTS), 10BaseT, unstructured DS1, structured DS1, frame relay, ATM25, serial ATM over T1, DS�3, OC�3, and OC�1. The customer premise locations will range from large enterprises (e.g., office buildings, hospitals, campuses), in which the microwave equipment is shared between many users, to mall locations and residences, in which single offices requiring 10BaseT and/or two POTS lines will be connected. Obviously, different customer-premise locations require different equipment configurations and different price points.
Standards

As LMDS wireless access systems evolve, standards will become increasingly important. Standards activities currently underway include activities by ATM Forum, the Digital Audio Video Council (DAVIC), the European Telecommunications Standards Institute (ETSI), and the International Telecommunications Union (ITU). The majority of these methods use ATM cells as the primary transport mechanism.

what is LMDS?

Hi guys,

thank you both , for your replys.It was very halpful for me.

regards

Re: what is LMDS?

Hi!
Hope you get all your questions about LMDS.
Do contact me if you require any further information.
Sincerely,
Singh