optimizing government and private wireless networks rev 1

Rev 1 Aug 19, 2005

Dekolink Wireless USA, Inc. PROPRIETARY of 7

Optimizing Government and Private Wireless Networks While deployment of a state-of-the-art wireless network is crucial to public safety, public utilities and many large enterprises, it represents a considerable investment. Therefore, it is imperative that the network is planned and deployed in such a way as to fully utilize the available capacity of the network and ensure coverage everywhere necessary, both indoor and outdoor. Most deployed base stations in public safety, utilities and private networks have underutilized capacity and do not provide complete coverage in the necessary area. Coverage is blocked by hills and valleys as well as by urban skylines. Some smaller remote communities and highways cannot be reached by a given base station but are too small to justify the cost of a separate base station. Many structures block the wireless signals from outside so vital communications inside buildings and tunnels are not possible with the base station alone. Dekolink Wireless offers a full line of unique products that operate seamlessly with the base station to permit a fully utilized network that provides complete coverage. These products include Tower Top Amplifiers, the Digital Channel Selective Repeater, Frequency Shift Repeater, Fiberoptic Repeater, and the Mid Power and Mini Repeaters for in-building coverage. Tower Top Amplifiers If one wants to increase the general coverage area of a cell site, the first step is to increase the base station transmit power by upgrading the power amplifiers. Then, mobiles just beyond the base station range of coverage can now receive signals from the base station. However, the base station receive sensitivity must also be improved proportionately so that those mobiles can also be heard by the base station (balanced coverage). The problem is that, in standard base station deployments, all of the active electronic equipment is housed in a climate-controlled shed at the base of the antenna tower. Thus, the additional RF loss through the coaxial cable from the tower top antennas and the first receive amplifier always degrades the base station receive sensitivity. The solution is the Dekolink Tower Top Amplifier (TTA). The TTA is a low noise

Figure 1. Dekolink Tower Top Amplifiers overcome the cable losses between the antenna and the base station electronics to increase base station sensitivity and permit an extended base station coverage radius.

Rev 1 Aug 19, 2005


amplifier that is mounted directly after the antenna on the tower, thus overcoming the initial cable loss and increasing the base station sensitivity (see Figure 1). The Dekolink TTAs are available for one sector or as a single box for three-sector sites. They are also available with duplexed transmit/receive connections that permit the transmit signal to pass through. This permits the use of TTAs without the need for additional cables. Dekolink TTAs have years of operational time in SMR networks in a wide range of harsh environments and have proven to be highly reliable, easy-to-install and cost-effective, providing an immediate return on investment.

Digital Channel Selective Repeater Dekolink’s Digital Channel Selective Repeater (DCSR) is a Dekolink-patented product, designed with the industry to boost SMR band users’ signals without adjacent channel interference. It is the only high power channel selective repeater that provides the channel selectivity and spectral purity needed in the busy SMR band. Up to eight individual, user-programmable filters can each pick out a single 12.5 kHz channel or up to 250 kHz of contiguous channels. The Dekolink Repeater Management Software provides easy, intuitive set up with a library of filter settings in drop down menus. With the off-air, remote monitoring, these settings can be changed by authorized technicians from anywhere to

Figure 2. Dekolink tri-sector Tower Top Amplifier with Power Distribution Unit.

Figure 5. Figure 5. Dekolink 10W SMR Digital Channel Selective Repeater.

Figure 3. The Dekolink Digital Channel Selective Repeater can be used for many applications including coverage hole fill and cell extension.

Rev 1 Aug 19, 2005


accommodate future network changes including the SMR rebanding. The DCSR is available for both the 800MHz and 900MHz bands. The Dekolink DCSR can be used to extend the cell coverage either beyond the normal range of the base station to outlying communities, or to provide “hole fill” behind hills, inside tunnels of inside buildings. Frequency Shift Repeater The Dekolink Digital Channel Selective Repeater can be configured easily by the user to accurately frequency shift the received channels. When used with a DCSR Frequency Shift Base Unit, the operator can provide dedicated coverage to remote sites with the unused capacity of the base station, which is otherwise, wasted investment. Channels from an opposing sector or new, dedicated sector are frequency shifted to unused channels in the existing coverage area. These channels are received by the Remote Unit that frequency shifts the channels back to their original channel assignments. A compelling advantage is that, since the receive and transmitted frequencies for the Remote repeater are different, the transmit/receive isolation

requirements are much lower permitting a physically compact remote site that is much less expensive and more practical in remote areas. This is illustrated in Figure 6. Note that the extended coverage area is a separate sector so there will be no interference in

Figure 6. A Frequency Shift Repeater as a BTS hotelling element. Here, a new sector B is added to an existing site. This is hard-wired to an FSR in order to provide full BTS coverage and capability to a new coverage area at a fraction of the capital and recurring costs of adding a whole new BTS.

Rev 1 Aug 19, 2005


the overlap area between the primary base station signal and the repeated signal. Also, dedicated coverage of a remote area has been provided at a very small fraction of deploying a new base station. Another application for the Dekolink Frequency Shift Repeater is highway and railway coverage. For these applications, a two-sector base station configuration is generally used to cover the highway or railway in each direction. The base station is usually underutilized in capacity in these applications so a Frequency Shift Repeater may be used to extend the coverage. This is illustrated in the Figure.

Fiberoptic Repeater

The Dekolink High Power Fiberoptic SMR Repeater can be used to fill in shadow areas in the cell coverage area and to bring dedicated channels (capacity) or a dedicated sector to a remote area (like the Frequency Shift Repeater described above). If a fiberoptic connection is available between the base station and the remote coverage area, the Fiberoptic Repeater may be used to provide the remote coverage. Only a single fiber is needed since the Dekolink Fiberoptic Repeater uses WDM (wave division multiplex)

Figure 7. Alternative highway coverage architecture using Frequency Shift Repeaters. N channels from the opposing sector are dedicated for remote coverage. The DCSR FSR shifts these channels to N unused channels in the donor link sector. The Remote Unit shifts the channels back. The overlapping coverage areas are unambiguous and non-interfering.

Figure 8. Dekolink High power Fiberoptic Repeater. The rack mounted FBIU is installed at the base station. The Remote Unit is a band selective unit with up to 10W composite power output.

Rev 1 Aug 19, 2005


technology. WDM is an optical diplexer that allows the transmit and receive signals to be carried over the same fiber since a different optical wavelength is used for each. There are two units in the Fiberoptic Repeater. One is the Fiber Base Interface Unit (FBIU), a rack mounted unit installed with the base station electronics. This unit converts the RF signal tapped off the base station transmitter to an optical signal. It also receives the optical signal from the Remote Unit, converts it back to RF, and delivers it to the base station receiver. The Fiberoptic Repeater can provide coverage to an area where there is no line of sight available to the base station. Since the donor link is a closed path, there is no transmit/receive isolation issues and the remote site is very compact; just the repeater Remote Unit and the coverage antenna (see Figure 9).

If the fiber is available, the Fiberoptic Repeater can provide a link between the base station electronics and the base station antennas when the separation between the two is too great for coaxial cable to reach without excess RF loss. In this case, the base station transmit signal is attenuated to a level needed to drive the FBIU. The Remote Units are placed at the antenna tower where needed. They are environmentally rated to be mounted outdoors without the need for an additional air-conditioned shed. In-Building Coverage Dekolink has a full range of repeaters to connect the outdoor network to indoor environments that are crucial to providing complete coverage such as office buildings, airports, and tunnels. Repeaters from 1/4W to 10W transmit powers provide spot coverage for smaller spaces to distributed coaxial systems with many indoor antennas for large buildings and tunnels. Dekolink repeaters are field proven with many thousands installed in the US alone. The SMR Mini-Repeater is a robust 1/4W driver for spaces up to 100,000 sq ft. One special feature is that it supports the SMR rebanding. It has three selectable bands that are preconfigured

Figure 10. Dekolink Mini-

basestation

FiberopticCable

Fiberoptic RepeaterRemote Unit

Figure 9. The Dekolink Fiberoptic Repeater can provide coverage to areas with no line of sight with the base station up to 20 miles away.

Rev 1 Aug 19, 2005


for the operator’s network. One band is for the operator’s present frequencies whereas the other two support the next two rebanding phases. With the wireless modem connected to the unit, these changes can be made remotely without having to visit the site. Summary For public safety, utilities and private networks, full utilization of the base station capacity and maximum coverage can be achieved by making Dekolink coverage solutions an integral part of the initial network design. Dekolink products are highly field-proven with many thousands deployed in US networks alone. All products can be remotely monitored and controlled. The products are:

• Tower Top Amplifiers (TTAs) o Increases the base station sensitivity; when used with increased base

station transmit power, extends the coverage range of the base station o Less than ½ the size and weight of competing systems – much easier to

install o Hundreds deployed in the US o Configurations available for any SMR band network

• Digital Channel Selective Repeaters (DCSR) o Dekolink patent o Designed with the industry o Only high power SMR band channel selective repeater to provide

needed channel selectivity, spectral purity and interference prevention o Easy set up and remote monitoring & control o Wide range of network applications

Cell extension Hole fill; fill in coverage within cell but behind hills, behind

buildings, inside buildings and tunnels Capacity enhancement – connect to underutilized neighbor cell

to bring additional capacity to focus area (stadium, convention center, etc.)

• Frequency Shift Repeaters (FSR) o Digital Channel Selective Repeater is the Remote Unit – paired with a

modified DCSR as the Base Unit (installed at the base station site) o Highly accurate frequency shift o Low isolation requirement means Remote site is physically compact

Low cost remote site Easy site acquisition Access to remote rural areas

o Can only be used in parts of the network that are not capacity limited o Permits full utilization of invested base station capacity o Creates a unique sector coverage area – overlapping base station and

repeater coverage areas have no interference (overlapping coverage with non frequency shift repeaters can cause interference between base station signal and time delayed repeater signal)

o Network plan that utilizes Dekolink FSRs will be far more price competitive than an all base station network design

Rev 1 Aug 19, 2005


• In-Building Coverage – Dekolink Repeaters o Dekolink offers repeaters with +24 dBm, +37 dB and +40 dBm

composite output powers – a solution for any building or structure from small, spot coverage (< 25,00 sq ft) to large stadiums and tunnels

o SMR Mini-Repeater (+24 dBm, 80 dB gain) includes Smart ALC and 3 selectable bands to support all three phases of SMR rebanding without changing hardware

• Fiberoptic SMR High Power Repeater o 10W (+40 dBm) composite output power o Up to 20 miles o Utilizes WDM (wave division multiplexing) so that only a single is

needed for the donor link o Option includes a second receive path for receive diversity o Extends coverage to shadowed areas where there is no available

remote site with line of sight to the base station o Can be used to connect base station to antennas on the tower when

there is no adjacent space to install both and the base station electronics must be located too far for a coaxial connection

o Can be used to bring dedicated channels (capacity) or a dedicated sector to a remote area

o Singlemode fiberoptic cable link must be available

optimizing government and private wireless networks rev 1

Documents