Using RRL allows for quick and inexpensive deployment of networks, and the independence of the cable infrastructure, making them very attractive for construction in remote and isolated from the wired infrastructure in the region, as well as in regions with difficult climatic conditions. Many experts in the field of wireless communications agree that without the widespread use of RRL is impossible to imagine a successful business development of mobile operators, which is observed in the present. Thanks to its reliability and flexibility of radio systems allow us to build up to a distance of 100 km, while ensuring high availability of the network operator (not less than 99.99 %).

It demanded the rapid deployment as a «point-mnogotochka» (PmP) in urban environments. PmP system is a key element that provides a fast and efficient broadband communications in networks, using traditional technology, and new generation networks. This system supports the organization of various services such as leased lines, high-speed Internet access, the association office LAN, virtual private networks (VPN) and the other at speeds up to 37 Mbit / s and with the allocation of a certain capacity to each user. The high efficiency of the use of radio frequencies is provided through the latest technology. And through the use of standardized units for the "point - the point" (PtP) and point - a lot of points "(PmP), these applications can now be implemented on the basis of a uniform - a hybrid of hardware platforms that provide cost savings to logistics and transaction costs.

1. Radio system PtP

1.1 frequency band used.

This criterion is the most common and does not affect the basic design features of RRL. It defines only the maximum distance of communication between objects. In the Russian Federation for the lines at the RRL, there is a sufficient number of allocated frequency bands from 2 to 58 GHz. This variety allows you to find the optimum mix between a range of communication and use a range of frequencies. The lower frequency bands (up to 13 GHz) are typically used for the construction of trunk routes sverhprotyazhennyh connection with a range up to 100 km. Frequency range from 13 to 23 GHz are used to build access networks the average length (50 km). The higher frequency bands are intended for the construction of access networks with a short passage, a range of not more than 10 - 15 km, which restricts the use of RRL in urban and suburban networks.

1.2 Capacity and type of traffic transmitted.

By this criterion RRL are divided into two main classes: SDH and PDH RRL. The first class includes all equipment RRL, transmitting signals PDH hierarchy, and having a bandwidth limited value 16h2 Mbit / s, although in recent times appeared RRL with a maximum capacity of up to 48h2 Mbps. A distinctive feature of such systems is the use of methods of modulation and coding with low spectral efficiency (no more than 1.5 bps / Hz), such as QPSK, CQPSK etc. This gives a large gain (105 dB or more), but leads to inefficient use of frequency resource. To send more data inefficiency use of spectrum limits the use of RRL PDH hierarchy, and to replace them come STM - 1 level of hierarchy SDH (155 Mbps). In contrast to PDH RRL in this class are essentially the methods of modulation and coding with high spectral efficiency (more than 3 bps / Hz), such as 16, 64, 128 QAM. Using such methods, modulation leads to a substantial reduction of system gain (typically 88 dB maximum, 100 dB), but can send in a given frequency band significantly more data.

1.3 Design features.

Despite the great diversity of all the design RRL constructively can be divided into two families: RRL internal mount (waveguide) and RRL with separate mounting (split mount). A fundamental difference between the equipment of these families is the placement of radio equipment. In RRL internal mount all the active equipment, including radio frequency, is placed inside the building (all indoor equipment). Connecting to the antenna by means of a waveguide (in the case of the use of antennas used dvuhpolyarizatsionnyh two waveguide). In contrast, RRL with separate mounting hardware is divided into internal units (indoor units), located inside the premises, and outdoor units (outdoor units), located near the antenna. The connection between modules is implemented using a coaxial cable that carries signals of intermediate frequency, and food outside the module. About ten years ago were also distributed RRL, in which all the active equipment located near the antenna, but at the present time, such RRL is not issued. There are many disputes about the place and the further development of internal RRL mount. Many experts consider reasonable, that in future this type of RRL RRL will be completely replaced with separate installation, due to compactness and lower cost of the latter. However, structural features of internal RRL montiranja allow to build the network, which principally can not be built on RRL with separate installation.

Cite these features:

• All active equipment is located inside the premises, which removes the practical limitations on the temperature range of the environment;
• RRL internal mount typically have a modular architecture that allows you to easily and safely (without any interruption of communication and enhance the deterioration of the system) to increase system capacity by adding frequency channels. For example, increasing the capacity of STM - 1 to 4 x STM - 1 easily feasible in RRL Internal mount with no loss of strengthening the system, while in RRL with separate installation is possible only without reserve, and the deterioration of gain 6.5 dB.
• Usually RRL Internal mount designed for low frequency bands (2 - 13 GHz), in which the main problem is the multipath radio wave propagation. To combat the sinking of this type uses the techniques of spatially separated. Quality of the spatially separated only in RRL internal mount.
• Using redundancy (1 +1) or (N: 1) a key parameter becomes the time of switching to reserve. In RRL internal mount this time does not exceed 25 ms, whereas in RRL with separate mounting this value is usually not less than 60 ms.

For these reasons, RRL internal mount is used as the main RRL, transferring large amounts of data over long distances. RRL separate mount, in contrast, are used in access networks.

2. Radio system PmP

Radio system PmP (point-to-mnogotochka) - this is a very good solution for broadband wireless communications, combining the latest technology in the field of radio communications. These systems provide the flexibility to manage traffic and various services in the field of information transfer.

R adioreleynye system PmP is a key element that provides a fast and efficient broadband communications in networks, using traditional technologies, and new generation networks. Such a system supports the organization of various services such as leased lines, high-speed Internet access, the association office LAN, virtual private networks (VPN) and to the allocation of a certain capacity to each user.

Equipment has interfaces E1 (structured / unstructured). The flexibility of the system allows the operator to provide high quality and diverse service (including the services of a traditional telephony networks), and a high peak load, while preserving the homogeneity of the structure of the network and reducing operating costs.

Scalable solutions to reduce the initial capital investment in the creation of a network and makes it possible to implement the principle of quick return on investment. Using standard interfaces guarantee a full interaction between the different parts and service network.

3. The hybrid radio system

hybrid radio system has a number of promising new functions and is designed for various applications in access networks and transport networks of cellular operators, as well as operators of fixed networks. Through the use of standardized units for the "point - the point" (PtP) and point - a lot of points "(PmP), these applications can now be implemented on the basis of a single hardware platform.

A greater degree of standardization ensures the reliability of planning and a substantial savings when compared with the expansion of the decisions on the basis of its own internal standards for the company. This makes it more responsive to changing market conditions, as it allows you to quickly and easily implement the necessary functions to support new or changing business models.