3G Handset and Network Design

Motorola proposed what turned out to be a rather overambitious project known as Iridium. Other vendor consortia, which included companies like Hughes and Raytheon with space sector experience, proposed similar projects. After a number of years, spectrum was allocated, and after a number ... [full story]

Satellite Networks In the 1980s, first-generation cellular systems generally provided quite poor geographic coverage. It varied substantially from country to country and from operator to operator, but typically you might experience demographic coverage of 70 percent to 80 percent of the population, which would ... [full story]

Setting the Stage for Satellite An alternative method of hiding RF and switch hardware, and avoiding the NIMBY factor, is to put the hardware up in the sky or into space. There have been a number of proposals and demonstration projects showing the ... [full story]

The NIMBY Factor One reason for hiding base stations and antennas is that if people don’t know that the hardware is there, they cannot complain about it—the “not in my back yard,” or NIMBY factor. Although it is well beyond the scope of ... [full story]

Alternative Fixed-Access and Mobility Access Wireless Delivery Platforms As we move up in frequency, particularly above 10 GHz, radio waves behave in a very similar way to light. We showed in Chapter 11 that it makes a lot of sense to do indoor RF ... [full story]

In common with wide area mobility networks, fixed-access wireless networks need to be able to handle bursty bandwidth. This means the same issues of protocol performance apply, albeit without the added complication of a mobility management overlay. Users in a ... [full story]

Because deployment is very line site sensitive, it is worthwhile to consider adaptive antennas that can search for the strongest signal and adapt to new signal paths as network density increases. These are known as mesh networks. Some meshed networks ... [full story]

There are also some attenuation peaks caused by water vapor and oxygen resonance effects. This is called resonant absorption. Attenuation peaks for water occur at 22 and 183 GHz. Attenuation peaks for oxygen occur at 60 and 119 GHz. Figure ... [full story]

Over the past 5 years, spectrum has been allocated on a country-by-country basis at 3.5 GHz, 10 GHz, 26 GHz, 28 GHz, 38 GHz, 39 GHz, and 40 GHz for broadband fixed wireless access. Available bandwidth increases as frequency increases, ... [full story]

Although there is presently considerable market focus on 2.4 GHz ISM-based networks, there are many radio channel allocations at lower frequencies that support radio telemetry and telecommand applications. The RF channel spacing may be either 12.5 kHz, 20 kHz, or ... [full story]

In a perfect world, devices would roam seamlessly between Bluetooth, IEEE, picocells, microcells, and macrocells (see Figure 15.2). Picocells, microcells, and macrocells work together very well but use substantial signaling bandwidth to achieve the happy state of effective communication. Getting ... [full story]

If Bluetooth or wireless LAN cards are added as plug-in modules, care must be taken if the Bluetooth or wireless LAN card relies on the host device for power. This would seriously compromise a PDA running on two AA batteries. ... [full story]

Bluetooth also needs to perform against an infrared port that is evolving over time. The ETSI/ARIB IrDAAIR (Area InfraRed) specification defines a point-to-multipoint capability in which multiple devices can be supported from a host device provided they are within a ... [full story]

In addition, Bluetooth needs to be delivered at a very low price point. The choice of FM helps reduce costs. There is no need for linearity in the PA, and you can use a simple FM modulator and FM discriminator. ... [full story]

It must be said that to date, most applications using Bluetooth have been one to one�" a host and slave device (handset and earbud, for example). In practice, it is very hard to develop consistent rules for joining and leaving ... [full story]

In practice, a real office environment typically requires an antenna gain of 10 to 20 dB because of the absorption and reflection from walls and furniture. In practice, performance across the radio physical layer is very variable if distances of ... [full story]

An added complication is that IEEE 802 shares spectrum with Bluetooth. Bluetooth provides an even more localized connectivity option—for example, to provide a localized RF connection between an earpiece/earbud headset and a cellular phone, or to connect a cellular phone ... [full story]

The challenge will be how to deliver a consistent user experience. Hot spots, such as airports and convention centers, are already saturated with cellular coverage, and the cellular networks often already occupy much of the available soffit space and conduit ... [full story]

The IEEE802 standard has been in existence for over 10 years, and a number of U.S. vendors have been producing wireless LAN products for commercial in-building applications, that is, private access networks. The idea is to extend wireless LANs into ... [full story]

Now let’s consider local area connectivity—for instance, a person in an airport. If a person is using a laptop to download a file, he will be more or less stationary. This is defined as a portable application rather than a ... [full story]

The trend over the past 15 years has been to infill macro sites (up to 35 km radius) with micro sites (500-meter radius) and to infill micro sites with pico sites (100-meter radius). This infilling is called a hierarchical cell ... [full story]

In the previous chapters in this part of the book we described how traffic is becoming increasingly bursty and how this exercises many of our system components. As user bit rate increases, and as the need for bandwidth quality increases, ... [full story]

The way we use the Internet has a number of interesting implications for offered traffic distribution. The average holding time for an Internet session is 30 times longer than a traditional voice call. Fortuitously, Internet busy hour is not the ... [full story]

What we really need most are applications that increase offered traffic loading in the off-peak hours in a network. Figure 14.7 shows a 24-hour loading of a cell site in Biggleswade, a rather sleepy suburban town in the United Kingdom ... [full story]

Content capture is also by nature asymmetric in the uplink direction. Surveillance devices and Web cams are uplink devices. However, value can be generated by archiving captured content. Captured content can then be redelivered to the originating subscribers. This is ... [full story]

We also need to consider the complexity of the exchange between users, users and devices, and devices. In a voice network, we have said that the exchange is essentially symmetric and duplex (bidirectional)—a point-to-point exchange. In a broadcast application, traffic ... [full story]

We have considered the additional cost implications of asymmetric traffic. Avoice network is a symmetric network; the uplink and downlink are balanced. Arich media network is by nature asymmetric, since asynchronous traffic is by its nature asymmetric. The asymmetry is ... [full story]

Thus we see that the shift in offered traffic (the need to preserve the properties of bursty bandwidth) fundamentally changes the way we have to treat traffic as it moves into and through the network. It is the job of ... [full story]

What we really need is to session switch. Here we set up a session, maintain a session, and clear down a session, with the capability to adapt to changes in session amplitude as the session progresses. This means we need ... [full story]

By overprovisioning delivery bandwidth, we can also reduce the need to provide traffic control mechanisms, which in turn absorb signaling bandwidth. As we start to reduce the amount of delivery bandwidth available, we start to have to prioritize bandwidth access—that ... [full story]

In a complex session we want and need to have continuous activity throughout the session. We also want to increase the length of the session—the persistency metric. Figure 14.6 shows an initial channel allocation at (a). Then successive channel additions ... [full story]

If we improve any of these quality metrics—frame rate, resolution, color depth—cost of delivery increases. The issue is whether tariff premiums can increase faster than the cost of delivery (see Figure 14.4). It is also difficult to calculate the real ... [full story]