802.11 Network

Multicarrier CDMA Techniques As discussed in the previous section, a multi-carrier scheme is used to implement an OC code–based CDMA system, if the FDM technique is used to send different element codes. There is big difference between an OC code–based ... [full story]

Bluetooth Technologies Bluetooth technology is based on a short-range radio specification defining transmission protocols between computers and other devices like cell phones and printers [462]. It was initially invented in 1994 by the Swedish L. M. Ericsson Company (who named ... [full story]

Ceiling-Tile Antennas In some cases, antennas must be totally hidden. This makes for an extremely tough installation. One possible solution is called a ceiling-tile antenna. Centurion Wireless Technologies offers such an antenna (see Figure C-5). Figure C-5. Armstrong Centurion Ceiling Tile Antenna [View ... [full story]

Sectorized Panel Antenna Although there are many different style of antennas possible for WLANs and wireless bridging, one specific antenna is particularly well suited for local outdoor coverage: a sectorized panel antenna (see Figure C-2). Many of the cellular telephone base-station ... [full story]

5-GHz Antennas Although most indoor 5-GHz products use permanently attached antennas, there is a big push to move 5 Ghz to the bands permitting external antennas. Presently, only a few antennas are available for the 5-GHz WLAN products, and many of ... [full story]

Longer-Range Directional Antennas Although most indoor systems do not require high-gain directional antennas, in some circumstances you might use a 10- or 13-dBi Yagi indoors to cover areas such as long corridors or long runs between high shelving (such as in ... [full story]

Panel or Patch Wall-Mount Directional Antennas Panel or patch antennas are designed to mount to a wall and provide coverage to an area such as an auditorium or large meeting room. They are fairly small in size and can even be ... [full story]

High-Gain Omni Antennas The antenna shown in Figure B-8 is a high-gain 12-dBi omni antenna from Mobile Mark Antennas. It is designed with no down tilt for use in long-range communication between sites with similar elevations. If the gain is very ... [full story]

Pillar- or Wall-Mount Omni Antennas Designed with the retail market in mind, the pillar-mount antenna pictured in Figure B-7 comes from Telex Communications. It was designed to be mounted to a building-structure pillar or to an inner-building wall. It also works ... [full story]

Mast-Mount Antennas Mast mount antennas come in many different styles, gains, and mounting capabilities. A mast-mount antenna can be used either indoors or outdoors. Be aware, however, that hanging a mast-mount antenna from a ceiling upside down might not work as ... [full story]

Ceiling-Mount Antennas One of the most common indoor mounting locations for an antenna is the drop-ceiling support grids. The AP can be located above the ceiling tiles, and the antenna placed below the ceiling (providing the AP has the proper ratings, ... [full story]

Dipole Antennas Dipole antennas are, by far, the most common antennas used for access points (APs). Many vendors manufacture them, and they come in various form factors. Some are hinged so that they can be positioned straight or at right angles, ... [full story]

WLAN Accessory Vendors Several other key products tie directly into WLAN networks. Such products include PoE devices, antennas, cables, and other accessories. This section provides just a sampling of some of these product offerings. PowerDsine PowerDsine leads the fast-growing PoE technology that allows ... [full story]

SOHO and Personal Use Many wireless products have been designed with the home office or small office in mind. Features and versatility required for enterprise and large corporate use are typically missing. Even the Wi-Fi Alliance has started distinguishing between such ... [full story]

Enterprise Class Wireless equipment intended for the corporate and enterprise markets have certain features and functions sought after by the IT staff of most corporationsthings such as 802.1x authentication, Wi-Fi Protected Access (WPA) certification, VLAN capability, Power over Ethernet (PoE) and ... [full story]

Installing Bridges Bridges typically fall into one of three general design categories: single-piece outdoor devices, single-piece indoor devices, or two-piece indoor/outdoor devices. Some systems have the entire bridge designed to withstand outdoor installations. This also permits the antenna to be attached ... [full story]

Interference Study Although the unlicensed spectrum offers the benefit of no licensing fees, users pay a penalty in terms of interference. There are no restrictions on the types of devices that operate in these bands, provided that they all conform to ... [full story]

Feasibility Study This section explains what is required to determine whether a successful bridge link can be accomplished. When determining the feasibility of a successful bridge link, you need to define how far the bridge link is expected to transit, at what ... [full story]

Using Common Applications over Bridges In the service provider arena, bridges are often used to tie multiple companies back to a single point of presence. However, the traffic needs to be separated for security and privacy reasons. Here, you can use ... [full story]

Understanding Bridge Topologies Two types of bridge topology are normally deployed. A large number of the systems are point to point, connecting just two locations together. Figure 14-1 shows a typical bridge topology for point-to-point systems. Figure 14-1. Point-to-Point Bridge Topology [View full ... [full story]

Understanding Bridge System Characteristics Ranges for bridge systems vary as a result of frequency, transmitter power, and available antennas. Ranges of a couple miles or less cover the vast majority of bridge installations; however, longer ranges can be activated with appropriate ... [full story]

Site Survey Report-Generation Programs Some programs offer report generators to assist in developing the necessary documentation, including site map coverage plans and equipment lists. This is one of the unique features to the AirMagnet tool that was discussed in Chapter 10, ... [full story]

Documenting the Work The site survey report describes the details that were completed as part of the survey and what might need to be done in the installation and configuration processes. When documenting the actual work, include specific details about the ... [full story]

Final Site Survey Report The customer needs the final site survey report to move forward with the WLAN installation. The customer and the installation team depend on the site survey engineer to provide them with all the information they need to ... [full story]

Ethernet Considerations When installing the APs, it is imperative to understand cable limitations for the data cable. If Category (Cat) 5 cable is going to be used, the AP must be located within 100 meters of the hub or switch to ... [full story]

Proper Antenna Mounting Antennas come in many different styles and form factors, and you have even more choices with mounting brackets. Some antennas are designed to be mounted to a mast, others to a drop ceiling, and others to a custom ... [full story]

Proper AP Mounting There are endless ways to mount APs. Some APs come with versatile mounting brackets that provide many options (see Figure 12-8a and 12-8b); others might offer only a simple keyhole mounting option (see Figure 12-8c), in which case ... [full story]

Understanding Installation Issues In many cases, the installation team is not the same individual or group of individuals who set down the initial design or performed the survey. However, the installation of a WLAN has to be closely tied to the ... [full story]

Final Verification Regardless of which site survey method you choose, conduct a walkabout for verification after the system has been installed. For this task, use the same tools and guidelines for boundary values as the manual survey uses. Perform a walkabout ... [full story]

Site Surveys for Voice As discussed previously in this chapter, WLANs used for voice require a little different survey approach. Table 11-3 indicated that the recommended signal strength, S/N ratio, and packet loss were much more conservative than those values used ... [full story]

Site Surveying for Repeater Usage Repeaters are supported by many of the WLAN products available today. However, the use of repeaters is recommended in only two scenarios: Locations where there is no possible way to wire the device If the installation will be ... [full story]

Assisted Site Surveys In an assisted site survey, you first need to determine how big a cell needs to be for the user density defined in the design. This might vary in different locations throughput the site, and this test will ... [full story]