Optimizing the use of docking network for mobile operators

Dario Pi Chivari, vice director of marketing and sales, Alcatel WTD, Italy, Milan
The third generation (3G) mobile network has higher requirements to connect base station (Gsm/gprs called BTS and UMTS called "Node B\ ')" (Universal terrestrial Radio Access Network-utran) in UMTS. High requirements come from the following: Increased number of sites, especially in densely populated urban areas
Increase in the amount of information processed per base station, increased load of access connections using ATM or IP as a transport format traffic load is very dependent on market share and business model, so that the size of the honeycomb, and thus also the evaluation of access line capacity is highly probabilistic the existing GSM network overlaps with the new 3G facility, both of which use the same access link.
Another problem is that it is becoming more and more difficult to obtain new sites for base stations in some countries, which has a significant impact on the overall planning of the docking network, as some sites have to be located at a non optimal location. Table 1 describes the three possible evolutionary backgrounds for determining UMTS specifications in a large Italian city (after the introduction of new services and the consequent increase in permeability). In the urban environment, the number of base stations is very large (in addition, the table does not take into account the micro-and Brett), the rate of each site is very high (the peak rate must be used for transmission network specification).
Table 1 prediction of urban, suburban and rural evolution
such as with GSM share access network, then should increase the capacity of 2mbit/s. The first impression is that 3G will result in highly dense nodes, with each node handling a large Brett rate. The access network that connects these nodes to the core network must handle such a large amount of traffic and meet the following traditional requirements:
Low cost of acquisition and operation
Effectively merge between new and existing devices
Good transmission quality and reliability
Flexibility and transparency (to support speed and standard gradual upgrades) scalability.
In real-world deployments, new networks typically have to be stacked on previously existing networks to maximize infrastructure use. But as long as it is completely brand-new 3G net, the freedom of planning is big.
Utran in Fig. 1UMTS

Microwave systems continue to play an important role in 3G, as they do in 2G and 2.5G. The point-to-point system (especially the local multicast system-LMDS, see Figure 2) will be widely used because:
The ratio of investment cost/support chain is good
Only modest planning work is needed
They support dynamic bandwidth allocation.
As long as it is possible to use point to multiple point system, the existing point-to-point connection to the demolition, to provide higher efficiency.
Figure 2LMDS System

Point-to-Point microwave systems (direct radio relay system-DRRS) will also be widely rolled out. Many of these systems have long been built into use. Where there is a potential to increase capacity to support new operations, DRRS can provide a simple and straightforward transition approach. Even where there is a bit of distribution to the multicast, a fixed point-to-point link will be used to feed the LMDS base station, or to a point outside the line of sight through other routes.
Clearly, it is not possible to establish common rules for GSM to 3G upgrades at this time, and it is necessary to find a solution for each situation, exploiting the possibilities offered by LMDS, Drrs and other media.
The main properties of the radio transmission system are:
Full range of equipment covering all licensed bands
Spectrum compression function
Ability to adapt to ATM and/or IP services
Flexibility of frequency and capacity (enabling the working channel to adapt to local interference environments and capacity to expand system capacity, extending from 2mbit/s to 16?2mbit/s or from STM0 to STM1 as required without replacing hardware)
If it is a synchronous digital series (SDH) radio, can be changed from simple regenerative relay function to full plug function, and hardware replacement to a minimum of low frequency devices (such as: 6, 7, 8GHz) have outdoor configuration of the availability of SDH outdoor system can be extended to 4+0/3+1 all wireless and wired ( A common management system (TMN) for optical fibres or copper wires.
These requirements are required, so the microwave system can adapt to the needs of developing networks because it is unlikely to be planned and developed in advance.
Network topologies are also important. The ring structure (see Figure 3) has many advantages as the volume of business required for 3G increases in density and flexibility requirements. The microwave ring has all the advantages (protection and flexibility) of the fiber ring, but it has one advantage: automatic selection of the highest mass transmission direction to prevent the propagation deterioration (e.g. attenuation or rain).

Fig. 3 Microwave ring Structure