Backhaul (telecommunications)
Encyclopedia
In a hierarchical telecommunications network
the backhaul portion of the network comprises the intermediate links between the core network
, or backbone
, of the network and the small subnetworks at the "edge" of the entire hierarchical network. For example, while cell phones communicating with a single cell tower constitute a local subnetwork, the connection between the cell tower and the rest of the world begins with a backhaul link to the core of the telephone company
's network (via a point of presence
).
would represent the spine, the backhaul links would be the limbs, the edge networks would be the hands and feet, and the individual links within those edge networks would be the fingers and toes.
Other examples include:
The choice of backhaul technology must take account of such parameters as capacity, cost, reach, and the need for such resources as frequency spectrum
, optical fiber
, wiring, or rights of way. Backhaul technologies include:
Backhaul capacity can also be leased from another network operator, in which case that other network operator generally selects the technology.
With mesh networks, access points are connected wirelessly and exchange data frames with each other to forward to/from a gateway point. Since a mesh requires no costly cable constructions for its backhaul network, it reduces total investment cost. Mesh technology’s capabilities can boost extending coverage of service areas easily and flexibly.
For further cost reduction, a large-scale mesh is desirable. To meet this challenge, a high capacity mesh is necessary.
Kyushu University's Mimo-Mesh Project, based in Fukuoka City, Fukuoka Prefecture, Japan, has developed and put into use new technology for building high capacity mesh infrastructure. A key component is called IPT, Intermittent Periodic Transmit. IPT is a proprietary packet-forwarding scheme that is designed to reduce radio interference in the forwarding path of mesh networks.
In 2010, hundreds of wireless LAN access points incorporating the technology were installed in the commercial shopping and entertainment complex, Canal City Hakata
, resulting in the successful operation of one of the world's largest indoor wireless multi-hop backhauls.
The wireless network deploying over 200 access point devices built inside Canal City Hakata realizes a wireless multi-hop relay of up to 11 access points while delivering high bandwidth to end users. Actual throughput is double that of standard mesh network systems using conventional packet forwarding.
Telecommunications network
A telecommunications network is a collection of terminals, links and nodes which connect together to enable telecommunication between users of the terminals. Networks may use circuit switching or message switching. Each terminal in the network must have a unique address so messages or connections...
the backhaul portion of the network comprises the intermediate links between the core network
Core network
A core network, or network core, is the central part of a telecommunication network that provides various services to customers who are connected by the access network. One of the main functions is to route telephone calls across the PSTN....
, or backbone
Backbone network
A backbone network or network backbone is a part of computer network infrastructure that interconnects various pieces of network, providing a path for the exchange of information between different LANs or subnetworks. A backbone can tie together diverse networks in the same building, in different...
, of the network and the small subnetworks at the "edge" of the entire hierarchical network. For example, while cell phones communicating with a single cell tower constitute a local subnetwork, the connection between the cell tower and the rest of the world begins with a backhaul link to the core of the telephone company
Telephone company
A telephone company is a service provider of telecommunications services such as telephony and data communications access. Many were at one time nationalized or state-regulated monopolies...
's network (via a point of presence
Point of presence
A point of presence is an artificial demarcation point or interface point between communications entities. It may include a meet-me-room.In the US, this term became important during the court-ordered breakup of the Bell Telephone system...
).
Definition
Visualizing the entire hierarchical network as a human skeleton, the core networkCore network
A core network, or network core, is the central part of a telecommunication network that provides various services to customers who are connected by the access network. One of the main functions is to route telephone calls across the PSTN....
would represent the spine, the backhaul links would be the limbs, the edge networks would be the hands and feet, and the individual links within those edge networks would be the fingers and toes.
Other examples include:
- Connecting wireless base stationBase stationThe term base station can be used in the context of land surveying and wireless communications.- Land surveying :In the context of external land surveying, a base station is a GPS receiver at an accurately-known fixed location which is used to derive correction information for nearby portable GPS...
s to the corresponding base station controllersBase Station SubsystemThe base station subsystem is the section of a traditional cellular telephone network which is responsible for handling traffic and signaling between a mobile phone and the network switching subsystem...
. - Connecting DSLAMs to the nearest ATMAsynchronous Transfer ModeAsynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...
or EthernetEthernetEthernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
aggregation node. - Connecting a large company's site to a metro EthernetMetro EthernetA Metro Ethernet is a computer network that covers a metropolitan area and that is based on the Ethernet standard. It is commonly used as a metropolitan access network to connect subscribers and businesses to a larger service network or the Internet...
network. - Connecting a submarine communications cableSubmarine communications cableA submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean....
system landing pointCable landing pointA cable landing point is the location where a submarine or other underwater cable makes landfall. The term is most often used for the landfall points of submarine telecommunications cables and submarine power cables. The landing will either be direct or via a branch from a main cable using a...
(which is usually in a remote location) with the main terrestrial telecommunications network of the country that the cable serves.
The choice of backhaul technology must take account of such parameters as capacity, cost, reach, and the need for such resources as frequency spectrum
Frequency spectrum
The frequency spectrum of a time-domain signal is a representation of that signal in the frequency domain. The frequency spectrum can be generated via a Fourier transform of the signal, and the resulting values are usually presented as amplitude and phase, both plotted versus frequency.Any signal...
, optical fiber
Optical fiber
An optical fiber is a flexible, transparent fiber made of a pure glass not much wider than a human hair. It functions as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. The field of applied science and engineering concerned with the design and application of...
, wiring, or rights of way. Backhaul technologies include:
- FSO Free space optics
- Point-to-point microwave radio relay transmission (terrestrial or, in some cases, by satellite)
- Point-to-multipoint microwave-access technologies, such as LMDSLMDSLMDS may refer to:*Los Mismos De Siempre - Abbreviated as LMDS, is fans of La Renga*Local Multipoint Distribution Service, abbreviated as LMDS, being microwave signals to transmit voice, video, and data signals for short distances...
, Wi-FiWi-FiWi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...
, WiMAXWiMAXWiMAX is a communication technology for wirelessly delivering high-speed Internet service to large geographical areas. The 2005 WiMAX revision provided bit rates up to 40 Mbit/s with the 2011 update up to 1 Gbit/s for fixed stations...
, etc., can also function for backhauling purposes - DSL variants, such as ADSL and SHDSL
- PDHPlesiochronous Digital HierarchyThe Plesiochronous Digital Hierarchy is a technology used in telecommunications networks to transport large quantities of data over digital transport equipment such as fibre optic and microwave radio systems...
and SDH/SONETSynchronous optical networkingSynchronous Optical Networking and Synchronous Digital Hierarchy are standardized multiplexing protocols that transfer multiple digital bit streams over optical fiber using lasers or highly coherent light from light-emitting diodes . At low transmission rates data can also be transferred via an...
interfaces, such as (fractional) E1/T1, E3, T3, STM-1/OC-3, etc. - EthernetEthernetEthernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
Backhaul capacity can also be leased from another network operator, in which case that other network operator generally selects the technology.
Mesh networks for wireless backhaul
As data rates increase, the range of wireless network coverage is reduced, raising investment costs for building infrastructure with access points to cover service areas. Mesh networks are unique enablers that can reduce this cost due to their flexible architecture.With mesh networks, access points are connected wirelessly and exchange data frames with each other to forward to/from a gateway point. Since a mesh requires no costly cable constructions for its backhaul network, it reduces total investment cost. Mesh technology’s capabilities can boost extending coverage of service areas easily and flexibly.
For further cost reduction, a large-scale mesh is desirable. To meet this challenge, a high capacity mesh is necessary.
Kyushu University's Mimo-Mesh Project, based in Fukuoka City, Fukuoka Prefecture, Japan, has developed and put into use new technology for building high capacity mesh infrastructure. A key component is called IPT, Intermittent Periodic Transmit. IPT is a proprietary packet-forwarding scheme that is designed to reduce radio interference in the forwarding path of mesh networks.
In 2010, hundreds of wireless LAN access points incorporating the technology were installed in the commercial shopping and entertainment complex, Canal City Hakata
Canal City Hakata
Canal City Hakata is a large shopping and entertainment complex in Fukuoka, Japan. Called the "city within the city," it boasts numerous attractions including shops; cafes; restaurants; a theater; game center; cinemas; two hotels; and a canal, which runs through the complex.Located adjacent to...
, resulting in the successful operation of one of the world's largest indoor wireless multi-hop backhauls.
The wireless network deploying over 200 access point devices built inside Canal City Hakata realizes a wireless multi-hop relay of up to 11 access points while delivering high bandwidth to end users. Actual throughput is double that of standard mesh network systems using conventional packet forwarding.
External links
- Debate: The Backhaul Battle Who Will Win? - Video 40 minutes, wide ranging.