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Backhaul

A_Simplified_Moble_Network
(Simplified Overview of a Mobile Network - Medium Technology)
 



The average American household consumes approximately 190 gigabytes of data per month on their home Internet connection and around 22 gigabytes on their mobile connection during the same time span. While these numbers may seem incredible, data usage across the U.S. is about to skyrocket with the advent of 5G and a whole slew of new IoT devices hitting the market. To remedy growing concerns over network congestion and instability, wireless providers are looking to not only upgrade their cell sites, but also the underlying infrastructure that connects these sites to the main data centers that power the Internet. This underlying infrastructure is known as backhaul and without a well-constructed network backhaul infrastructure, it will be difficult to future-proof current networks against rising bandwidth demands, making this a vital consideration for the future accessibility of the Internet.

Base stations that move data between the fiber optic backhaul and wireless “last mile” will use Massive Multiple Input Multiple Output (MIMO) technology to greatly increase the bandwidth by a factor of five or more over current base stations. To avoid signal interference from all of these additional signals, beamforming technology will reduce interference by allowing base stations to send a focused stream of data to a specific user rather than sending the signal in every direction. Full-duplex technology will allow send and receive signals to be sent simultaneously rather than one after the other, a major driver behind latency reductions expected with 5G. Underpinning all of this wireless technology will be a next-generation fiber optic backhaul that utilizes full duplex technology to transport large quantities of data over distance.

 

Backhaul: The Backbone Portion of the Telecom Network

 

- Backhaul's Key Role: To Carry Packets to and from the Backbone Network

In a hierarchical telecommunications network the backhaul portion of the network comprises the intermediate links between the core network, or backbone network and the small sub-networks at the "edge" of the entire hierarchical network.

In contracts pertaining to such networks, backhaul is the obligation to carry packets to and from that backbone network. A business definition of backhaul is the commercial wholesale bandwidth provider who offers quality of service (QOS) guarantees. It appears most often in telecommunications trade literature in this sense, whereby the backhaul connection is defined not technically but by who operates and manages it, and who takes legal responsibility for the connection or uptime. 

In both the technical and commercial definitions, backhaul generally refers to the side of the network that communicates with the global Internet, paid for at wholesale commercial access rates to or at an Internet exchange point or other core network access location. Sometimes middle mile networks exist between the customer's own LAN and those exchanges. This can be a local WAN connection. 

Please refer to [The Internet Backbone] for more details.

 

-  Future Mobile Network More On Machine-Centric

It is clear that the future mobile network (i.e., 5G) will no longer human centric, it will be more on machine centric which will interconnect billions of smart devices to the mobile network. Recent research and standardization work have been addressing requirements and challenges from radio perspective (e.g., new spectrum allocation, network densification, massive multiple-input-multiple-output antenna, carrier aggregation, inter-cell interference mitigation techniques, and coordinated multi-point processing). In addition, a new network bottleneck has emerged: the backhaul network which will allow to interconnect and support billions of devices from the core network. Up to 4G cellular networks, the major challenges to meet the backhaul requirements were capacity, availability, deployment cost, and long-distance reach. However, as 5G network capabilities and services added to 4G cellular networks, the backhaul network would face two additional challenges that include ultralow latency (i.e., 1 ms) requirements and ultradense nature of the network. Due to the dense small cell deployment and heavy traffic cells in 5G, 5G backhaul network will need to support hundreds of gigabits of traffic from the core network and today’s cellular backhaul networks are infeasible to meet these requirements in terms of capacity, availability, latency, energy, and cost efficiency. 

 

- Backhaul Technologies

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 internet service provider's network (via a point of presence). A backhaul may include wired, fiber optic and wireless components. Wireless sections may include using microwave bands and mesh and edge network topologies that may use a high-capacity wireless channel to get packets to the microwave or fiber links.

Backhaul technologies include:

  • Wireless: Point-to-point microwave radio relay transmission (terrestrial or, in some cases, by satellite); Point-to-multipoint microwave-access technologies (such as Wi-Fi, WiMAX, etc.), TV White Space. Wireless backhaul is easy to deploy, and allows moving points of presence, however, these wireless connections are slower, occupy spectrum that could be used by user devices (especially as 5.8 GHz devices proliferate), require more service/maintenance calls as wired backhaul, are limited in bandwidth. They are often viewed as an initial or temporary measure. 
  • Wired: (such as leased lines or copper/fibre). Optical Based: SDH/SONET/DWDM. Wired is usually an expensive solution but offers practically unlimited bandwidth and ease of maintenance. 
 

-  Major Backhaul Upgrades for 5G

To bring the 5G network in reality, a simple upgrade of mobile network will not be enough where we just add new spectrum and enhance the capacity or use advanced radio technology. It will need to upgrade from the system and architecture levels down to the physical layer. Although some research and standardization work addressing the corresponding challenges from radio perspective (e.g., new spectrum exploration, carrier aggregation, network densification, massive multiple-input-multiple-output, and inter-cell interference mitigation techniques) but there is a new challenge has emerged: the backhaul. 

5G is going to need a lot of backhaul upgrades. Globally, the average backhaul is less than 5 Mbps. Much of the existing backhaul network in America is a really low capacity network. And when 5G starts to become pervasive, and it’s delivering speeds over 1 Gbps. We need a new backhaul network. 

When mobile carriers are building their 5G networks they have to select vendors in three key areas: They have to pick a radio vendor; they need a backhaul vendor to rebuild their network because the current network can’t handle the 5G speeds; and they need a 5G core vendor.

 

 

[More to come ...]


 


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