Local Loop

In telephony, a local loop is the wired connection from a telephone company's central office in a locality to its customers' telephones at homes and businesses. This connection is usually on a pair of copper wires called twisted pair. The system was originally designed for voice transmission only using analog transmission technology on a single voice channel. Today, your computer's modem makes the conversion between analog signals and digital signals. With ISDN or Digital Subscriber Line (DSL), the local loop can carry digital signals directly and at a much higher bandwidth than they do for voice only.

An access circuit from the network edge to the customer premises, a local loop is a short haul circuit for access to a local exchange. The most common example of a local loop is an electrically based, two-wire, copper access circuit between a telephone company central office (CO) switching center and a residential or small business premises. Such a circuit is provisioned over a single unshielded twisted pair (UTP), within which two wires are required to complete the electrical circuit, with the current in one wire opposite to the current in the other, and with both wires carrying the information signal. The two conductors comprise an electrical loop, with one wire carrying the go signal and the other carrying the electrical return signal. In the broader contemporary sense, any access circuit between the customer premises and the edge of the telco network, or that of any other service provider, is termed a local loop, whether it is electrically based or employs optical or radio energy. During the transmission of the data transmission lines mainly suffer three kinds of losses:

Attenuation:-The Loss occurred due the loss of energy.

Distortion:- Due to the propagation speed v/s frequency.

Noise:-it is unwanted energy from source other then the transmitter.

Wireless Local Loop (WLL)

WLL is a feature implementation using a serving system that utilizes a wireless connection to a wireless device, such as a mobile station or a network interface unit to provide local loop service to an end user. WLL permits local loop service for subscriber call origination and for receipt of calls. WLL applies to voice and data services. WLL provides signaling mechanisms between the serving system and the mobile station or the network interface unit. This signaling mechanism permits the exchange of call control information.

The essential signaling elements of WLL are:

Mobile Station or Network interface unit Device Type specification and request for WLL of the serving system or optional serving system Device Type specification

Mobile Station or Network interface unit Dial Tone or optional Dial Tone of the serving system

Mobile Station or Network interface unit Hook Status enabling WLL call control of the serving system

Serving system Autonomous Message Interval specification and request of the mobile station or the network interface unit or optional network interface unit Autonomous Message Interval specification

Serving system Call Waiting Indicator notification to the mobile station or the network interface unit

Local Loop Unbundling (LLU)

LLU refers to the possibility for entrants on the broadband market to access the incumbent’s local loop and provide service using their own backhaul network. While LLU allows entrants to operate under (possibly) lower marginal costs, it involves important ex ante investment.

At present, LLU seems most promising as a means for entrants to offer broadband internet access. As voice telephony can be implemented by using the ‘internet protocol’ when consumers have broadband access, LLU may, in the end, spur competition in markets for voice telephony as well. Thus LLU is an important way to stimulate competition in the broadly defined market for fixed telecommunications.

In telecoms, unbundling usually implies wholesale leasing of the local loop. In other markets, unbundling can be interpreted more broadly. More generally, unbundling can be seen as a method of implementing ‘one-way’ access to an incumbent’s network. Unbundling typically implies that the incumbent’s essential input (and perhaps others as well) is, at the wholesale level, ‘separated’ from its overall facilities or operations, in order to allow for commercial wholesale supply of this input. Hence, although it is typically discussed within the framework of telecommunications, it has wider relevance. In postal markets, for instance, through unbundling regulators may enforce access to the incumbent’s system for local mail delivery (access to ‘the postman’). Unbundling of the postal value chain, a notion known as worksharing, allows competitors to buy the incumbent’s delivery function, and perhaps others as well, such as the sorting of mail items. In electricity, regulators may mandate access to electricity companies’ local distribution networks. In financial securities trading, the book depository function (the legal records of ownership changes) may be unbundled from the broad set of clearing and settlement services.