Mobile Air Interface and Mobile Backhaul

- Overview

Mobile air interface (MAI) is the radio frequency part of the circuit that connects a wireless modem or cellular phone to a base station. Mobile backhaul (MBH) is the process of connecting cell site air interfaces to wireline networks. 

MBH is a transport network that connects the core network and the Radio Access Network (RAN) of a mobile network. It's essential for 5G networks to ensure fast, reliable, and seamless communication by transmitting data from small cellular sites to a central network point. MBH also provides capacity, reliability, and transmission delay to RAN. 

Backhaul technologies include:

• Free-space optical (FSO)
• Point-to-point microwave radio relay transmission
• Point-to-multipoint microwave-access technologies, such as Wi-Fi, WiMAX, and LMDS
• DSL variants, such as ADSL, VDSL, and SHDSL
• PDH and SDH/SONET interfaces
• Ethernet
• VoIP telephony over dedicated and public IP networks

Please refer to the following for more information:

• Wikipedia: Air Interface
• Wikipedia: Backhaul

- Mobile Air Interface Technology

Some of the most common acronyms used in the discussion of wireless are those that describe the air interface method of a wireless network. The air interface, or access mode, is the communication link between the two stations in mobile or wireless communication. 

The air interface involves both the physical and data link layers (layer 1 and 2) of the OSI model for a connection. 

In cellular telephone communications, the air interface is the radio-frequency portion of the circuit between the cellular phone set or wireless modem (usually portable or mobile) and the active base station. As a subscriber moves from one cell to another in the system, the active base station changes periodically.

The air interface technology specifies the method for transmitting information over the air between base stations and mobile units. Most air interface technologies are specified in standards that are agreed upon by multinational bodies comprising representatives in the wireless industry. 

Some air interface methods, however, remain proprietary with certain companies and details of their operation may or may not be publicly accessible.

- The 5G NR (New Radio) Air Interface

5G New Radio (NR) is the radio access technology (RAT) that serves as the global standard for the air interface of fifth generation (5G) mobile networks. The 3rd Generation Partnership Project (3GPP) developed 5G NR to enable wireless connectivity for anyone and anything, anytime and anywhere. 

It uses a variety of advanced technologies to improve network efficiency and capabilities, including:

• Orthogonal Frequency-Division Multiplexing (OFDM)
• Beamforming
• Massive MIMO
• Small Cells
• Dynamic TDD
• Low density parity check codes (LDPC)

5G NR also features adaptive bandwidth across two frequency ranges:

• Frequency range 1: Up to 6 GHz and below
• Frequency range 2: Within 20–60 GHz, including the millimeter frequency range, which is important for 5G ultra-wideband (UWB)

5G NR is designed to support the growth of wireless communication by:

• Increasing the amount of data transmitted over a given spectrum
• Supporting fiber-equivalent bandwidth transmissions
• Supporting low-bandwidth transmissions for machine-to-machine communications

5G NR is expected to deliver faster and more responsive mobile experiences, and to redefine and connect many new industries.

- Mobile Backhaul

Mobile Backhaul (MBH) is the process of connecting cell site air interfaces to wireline networks, which are subsequently connected to data centers that host the content and applications accessed by mobile users - both human and machine.  

Manufacturers of network switching equipment use the term backhaul to refer to the process of getting data to the Internet network backbone, for example, by packet-based Carrier Ethernet solutions that offer robust, scalable, and cost-effective MBH network designs. 

Mobile networks are increasingly the most popular vehicles for accessing remote content. But the data flying through the airwaves is only half the story. MBH is what happens behind the scenes to move data from the cell sites to data centers and other points along the way.

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 subnetworks at the edge of the network. 

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). 

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). 

[More to come ...]