Under WISP we understand an integrated Metropolitan Area Network (MAN) system of connecting customers to the Internet. High-speed wireless datalinks are used to provide Internet access on a point-to-point and point-to-multipoint basis for companies, governmental organizations, schools, universities and other institutions having Local Area Networks (LAN).
Narrowband Technology A narrowband radio system transmits and receives user information on a specific radio frequency. Narrowband radio keeps the radio signal frequency as narrow as possible just to pass the information. Undesirable crosstalk between communications channels is avoided by carefully coordinating different users on different channel frequencies. Spread Spectrum Technology Most wireless LAN systems use spread-spectrum technology, a wideband radio frequency technique developed by the military for use in reliable, secure, mission-critical communications systems. Spread-spectrum is designed to trade off bandwidth efficiency for reliability, integrity, and security. In other words, more bandwidth is consumed than in the case of narrowband transmission, but the tradeoff produces a signal that is, in effect, louder and thus easier to detect, provided that the receiver knows the parameters of the spread-spectrum signal being broadcast. If a receiver is not tuned to the right frequency, a spread-spectrum signal looks like background noise. There are two types of spread spectrum radio: frequency hopping and direct sequence.
Frequency-Hopping Spread Spectrum Technology Frequency-hopping spread-spectrum (FHSS) uses a narrowband carrier that changes frequency in a pattern known to both transmitter and receiver. Properly synchronized, the net effect is to maintain a single logical channel. To an unintended receiver, FHSS appears to be short-duration impulse noise. Direct-Sequence Spread Spectrum Technology Direct-sequence spread-spectrum (DSSS) generates a redundant bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code). The longer the chip, the greater the probability that the original data can be recovered (and, of course, the more bandwidth required). Even if one or more bits in the chip are damaged during transmission, statistical techniques embedded in the radio can recover the original data without the need for retransmission. To an unintended receiver, DSSS appears as low-power wideband noise and is rejected (ignored) by most narrowband receivers.
All customers are using the same 11Mb/s channel. This configuration can be used for unlimited number of clients. The link between the Base Site and the clients is 11 Mb/s. If additional Ethernet NIC is installed in the wireless router located in a building, then more than one client network can be connected to the wireless router. Each of the client networks are separated from each other since they are connected to different interfaces of the router. The bandwidth management can be done at at the Ethernet/Ethernet router located at the ISP.
All customers are using the same 11Mb/s channel. The Internet Service Provider is also using this channel. This means that there is no "backbone" to the Base Unit. This configuration can be used for five to ten LANs from 5 to 50 computers each. The link between the Repeater Site and the clients is 5.5 Mb/s. It is possible to connect one more MikroTik router (so one more LAN) to the Base Unit on the building using Ethernet Cable. The link between the ISP and the client located at the repeater site is 11 Mb/s.
All customers are using the same 11Mb/s channel. The Internet Service Provider is also using this channel. This means that there is no "backbone" to the Base Unit. This configuration can be used for five to ten LANs from 5 to 50 computers each. The link between the ISP and the wireless clients is 5.5 Mb/s. It is possible to connect one more MikroTik router (so one more LAN) to the Base Unit on the building using Ethernet Cable. The link between the ISP and the client located at the repeater site is 11 Mb/s.
Base Unit has 11Mb/s channel. Internet Service Provider has a separate backbone link going to the Base Unit. All customers are using the same 11Mb/s channel. This configuration can be used for unlimited number of clients. The link between the Base Site and the clients is 11 Mb/s.
You can connect two Local Area Networks using two MikroTik routers and point-to-point link. So there will be 11 Mb/s channel between two LANs. This configuration is used in the Backbone Setup. There is a point-to-point link between the ISP and the Base Site.