City-A. Fast Ethernet MM-wave Radio of Point-to-multipoint Topology

City-A was designed to construct wideband IP-networks in urban areas. City-A is operating in 40.5-43.5 GHz band, allocated in EU for broadband communications.

City-A set consists of Switch and Terminals. The Switch is deployed on height dominating building. Terminals are deployed on line-ofsight positions within Switch service area. One terminal can serve a bunch of offices, apartments, houses etc. City-A operates like a Fast Ethernet Router. IP-packets, incoming to Terminal, are forwarding to Switch or, via Switch, to Terminal front-end. IP-packets, incoming  to Switch, are forwarding to Terminal of destination.

Both Switch and Terminals have Fast Ethernet interfaces. They can be connected to any network equipment directly.

Downstream channel (Switch to Terminals) capacity is 100 Mbps. Total upstream channel capacity (Terminals to Switch) is 100 Mbps as well. There are no collisions in City-A system. The losses for system management in downstream are less than 0.5%, in upstream – less than 10%. So, the real City-A capacity is about 200 Mbps independently on any external circumstances.

Non-collision operation is provided by the following:

1. Downstream and upstream are operating in different frequency bands. Downstream capacity does not depend on the upstream channel load and vise versa.

2. Terminal dishes have very small beamwidth (0.7° to 2°). The data transmitting from one Terminal does not affect on the data receiving by other Terminals.

3. To eliminate collision at Switch receiver, all Terminals transmits in TDMA mode, one after another, according to instructions issued by Switch. Period and duration for any Terminal is assigned during the system configuration or automatically.

Is provided by 2 factors:

1. It is very difficult to find 40.5-43.5 GHz equipment on the market for spy data trapping.

2. Due to very small Terminal beamwidth (only 2 times more than in laser free optical systems) the data interception, even having appropriate equipment, is as difficult as in optical systems.

City-A was designed to provide a necessary quality in IP-phone communications. Downstream delay is less than 1 ms. Upstream delay is 0.5 .. 1 ms per operating Terminal.

An Operator can deploy a number of City-A systems on the same territory. City-A Switch is completed by 30, 45, 60 or 90° sector antenna. Accordingly, the operator can deploy 4, 6, 8, or 12 Switches in the same point (to eliminate interference, different polarizations are used in adjacent sectors). So the total network capacity can be increased up to 1.2 Gbps, full duplex.

To connect more terminals or cover wider area, several cells can be deployed.

Cuty-A is designed based on 2 key components: Switch and Terminal. The Switch consists of ODU and IDU. The ODU is a transceiver with sector antenna. IDU is built on the base of computer and installed in the office. ODU and IDU are connected with «twisted pair» cable. The Switch IDU can be connected to Internet router, Billing&Authorization system etc.

The Terminal is also consists of ODU and IDU, connected to each other by «twisted pair» cable. Terminal IDU is connected directly to LAN.