Technology

Wide Area Wireless Network - Airvenue System, a HC-SDMA - based technology

Airvenue System Airvenue system is a Mobile Broadband Wireless Access System based on SDMA/TDMA-TDD technologies and designed for telecom carriers who would like to provide high quality wireless broadband internet access service with limited resource of frequency. Airvenue system has been standardized in ANSI as HC-SDMA since September, 2005, in ITU-R as M.1801 since March, 2007. General operational band for Airvenue is 1785-1805MHz or 1900MHz-1920MHz, and only requires 5MHz bandwidth for operation because of its high spectral efficiency. With this bandwidth, Airvenue provides up to 24Mbps data throughput per Base Station or 1Mbps per user data access (downlink) for up to 24 concurrent users with mobility and competitive price. Its simple system architecture also makes installation easy and flexible Airvenue system has been deployed in 11countries by 12 operators in the world. Several kinds of user terminal are available to satisfy various application requirement of end-customers, such as card type, desktop type, USB type terminals. For VoIP application, SIP phone type terminals are available for use.


	Outstanding Features High Data Rate System capacity 24.4Mbps downlink/ 7.9 Mbps uplink Data Rate of 1.061Mbps downlink/ 346Kbps uplink High Spectral Efficiency 3.4 bit/sec/Hz/cell (WIBRO 802.16e: 1.5 bit/sec/Hz/cell) Wide Area Coverage Up to 12.75km using 1.79 GHz or 1.9 GHz (40% greater than WiMax) Good non-line-of-sight indoor penetration Mobility Support user in motion at speed greater than 100 km/hour and seamless handover between Base Stations Easy Interface to IP Network All IP based simple network of Airvenue enables substantial reduction of network investment VoIP Compatibility QoS is implemented to ensure high quality wireless VoIP telephony

	OVERALL LOW COST OF OWNERSHIP

Wireless Mesh IP Network based on 802.11 a/b/g specification

In an Airvenue solution, each platform supports backhaul coverage in all directions using antennas in a circular array. The antennas have a high gain and a narrow horizontal beamwidth, which together with enhanced radio performance, provide significant reach extension.

The three backhaul radios in each platform can automatically connect to any one of the eight backhaul antennas with no need for manual pointing. The selection is done under software control via autoantenna selection algorithm.

System availability is ensured through a combination of techniques:

The radio environment is constantly changing and the radios adapt to these changes on a packet-by-packet basis. In addition, dynamic power and data rate changes on individual radio links compensate for radio effects such as fading and shadowing.
Radio-aware routing algorithms choose the best route for traffic based on available capacity, latency and radio link performance.
To increase system up-time and minimize traffic outages, traffic from each broadband platform can be load balanced across a minimum of two routes to reduce the impact of link congestion and failure.
Alternate paths are continuously calculated and refreshed so that seamless re-routing of traffic can occur with minimal packet loss in the unlikely event of a link failure.

An Airvenue solution can easily scale to meet increased network demand. New platforms can be incorporated into the network automatically, without complex operator intervention.

A network can be deployed with a single egress point (point of presence) in the early days, and as usage increases, additional egress points can be added for increased capacity and redundancy through multi-homing.

Benefits

The Airvenue cellular LAN delivers guaranteed backhaul performance for throughput and latency.

It uses three independent channels, each with highly directional antennas, which allows for excellent frequency reuse.

And it does not share spectrum for access and backhaul.

As a result of these innovations, the Airvenue solution provides five to ten times more radio capacity compared to traditional mesh solutions.

In addition, directional antennas used in the Airvenue cellular LAN add 15 dB to the backhaul link budget. This allows the multi-service platforms to operate at distances five times greater than other mesh systems.

As a result of these innovations, the Airvenue cellular LAN:

eliminates the need for cables and additional switches and routers to interconnect wireless nodes
requires five to ten times fewer access points compared to indoor solutions
eliminates disruptive, in-building network deployment
reduces WLAN capital expenditures by up to 70%
reduces WLAN operating expenditures by up to 90%
eliminates T1, DSL and other backhaul costs
provides five to ten times more capacity and five times more coverage compared to traditional wireless mesh architectures

Mesh Networking Option

Single Radio Mesh

In a single radio mesh, each mesh node acts as an access point that supports local clients and also forwards traffic wirelessly to other mesh nodes. The same radio is used for access and wireless backhaul.

This approach requires that almost every packet generated by local clients must be repeated on the same channel in order to send it to at least one neighboring node in the mesh. The packet is then forwarded to another node in the mesh and ultimately to a node that is connected to a wired network.

This packet forwarding generates a lot of traffic. As you add more mesh APs, a higher percentage of the wireless traffic in any cell is dedicated to forwarding. Very little of the channel capacity is actually available to support users.

Also, in a single radio mesh architecture all clients and mesh nodes must operate on the same channel. As a result, the entire mesh ends up acting like a single, giant access point—all of the mesh nodes and all of the clients must contend for a single channel.

For this reason, single radio wireless mesh architectures don’t deliver enough capacity for broadband service and can’t scale. As you add more mesh nodes, the system capacity gets worse.

Single radio mesh networks are fine for free community networks where service expectations are low and ad-hoc networks where the emphasis is on basic connectivity. But they are not ideal for large broadband deployments.

Dual Radio Mesh

Infrastructure wireless mesh networks designed for large deployments should use mesh nodes built with multiple radios. The most basic multi-radio approach is the dual-radio mesh.

In a dual-radio mesh, the nodes have two radios operating on different frequencies. One radio is used for client access and the other radio provides wireless backhaul. The radios operate in different frequency bands so they can run in parallel with no interference.

In a dual radio wireless mesh the scaling problem encountered in single radio mesh designs is solved with mesh forwarding.

Since the mesh interconnection is done with a separate radio operating on a different channel, local wireless access capacity is not affected by traffic forwarding. However, there is still a scaling issue that limits capacity as the network grows. But in this design, the scaling problem is with the wireless backhaul.

In a dual-radio design, the wireless backhaul mesh is a shared network. With only one radio dedicated to backhaul at each node, all of the mesh nodes must use the same channel fairly in order to get backhaul connectivity and participate in the mesh. Parallel operation is not possible and most of the mesh APs hear multiple APs.

The APs must contend for the channel and they generate interference for each other. The result is reduced system capacity as the network grows.

Multi-Radio Mesh

Like a dual-radio wireless mesh, a multi-radio wireless mesh also separates access and backhaul, but it goes a step further in order to provide increased capacity, reliability and scalability.

Additional radios in each mesh node are dedicated to the wireless backhaul. The backhaul mesh is no longer a shared network. It is built from multiple point-to-point wireless links and each of the backhaul links operates on different independent channels.

When used as a backhaul in this fashion, the performance of a multi-radio mesh is similar to switched wired connections between the mesh nodes.

The mesh radios operate independently on different channels so latency is very low. There are only two nodes per link, so contention is very low. In fact, it is possible to run a customized protocol on the backhaul links that optimizes throughput in this simple contention free environment.

Performance in a multi-radio mesh is much better than the dual radio or single radio mesh approaches.

The mesh delivers more capacity and scales up as the size of the network is increased—as more nodes are added to the system, overall system capacity increases.

Applications

The purpose of a wireless mesh is to support WiFi clients and applications.

A multi-radio wireless mesh architecture is the only one capable of providing multiple, high-capacity networks that can be custom-configured to meet public and private service and application needs.

For example, in a metro multi-radio mesh deployment, one network can be dedicated to provide public high-speed Internet access. At the same time, other secure networks can support essential service communications for police, fire, and ambulance.

And a multi-radio mesh is the only one capable of delivering the network bandwidth to handle multiple simultaneous connections for high capacity data, voice and video services.

Airvenue System

Outstanding Features