Wireless delivery alternatives
Feb 1, 2007 12:00 PM, By Kevin McNamara, CNE
The proliferation of wireless access in our country will soon reach a point of surpassing wireline delivery. Many people have cancelled their plain old telephone service and now exclusively use wireless mobile phones. Wireless hotspots are popping up everywhere; in fact, many of these are provided free of charge in stores, restaurants and other public areas.
The fact is that wireless delivery platforms are becoming faster, more reliable and cover a greater range than anyone would have imagined only a few years ago. Along with the improved performance, the cost to deploy these systems has fallen into the range where most people can afford to convert. For broadcasters, these alternatives can be applied to a wide range of program and data transmission applications.
Wi-fi is defined as the IEEE 802.11x standard. It was first introduced by Lucent and NCR in 1991. The first standards for 802.11a and 802.11b were ratified in 1999. The �a� version operates in the allocated 5GHz spectrum and provides data rates up to 54Mb/s, while the �b� version uses the 2.4GHz spectrum and delivers a maximum 11Mb/s. In 2003, the enhanced 802.11g standard improved the performance of 802.11b, permitting increased data throughput to 54Mb/s on the 2.4GHz spectrum. The ranges on all of these versions were specified to a maximum of 30 meters.
The 802.11n standard is currently being drafted. It defines a method to dramatically increase the performance of all previous 802.11 versions. Data rates are increased to a maximum of 540Mb/s and the range increases up to 125 meters (line of site outdoors). Several other versions of the 802.11 standard are currently with various working groups. These new versions will provide additional features such as extended range, interoperability with cell phone technologies and even a specification to support using Wi-fi in a mobile environment.
Perhaps the most exciting technology for broadcast applications is called Wi-max, which is an acronym for Worldwide Interoperability for Microwave Access. The IEEE standard designation is 802.16x. This technology, while compatible with 802.11x equipment, is designed to deliver high-speed broadband coverage over a wide area, or to provide last-mile coverage to areas not served by wireline carriers.
Wi-max requires significantly more bandwidth and power than Wi-fi, which means that Wi-max needs to operate in other spectrum than that allocated for 802.11x. The current Wi-max specification (802.16e) does not specify particular frequencies where it will operate; rather, it specifies a large range of frequencies (about 2GHz to 60GHz). The lower frequencies are intended to support a mobile network, similar to that of a typical wireless telephone carrier.
I think Wi-max will have some interesting applications in a broadcast environment, perhaps as a replacement to the station's RPU system or even an STL link. It should be possible that a single Wi-max system deployed on a multi-station transmitter facility could more than support the needs of every station using the site.
To expand this concept, consider that the same system might also support remote broadcasts, including two-way communications with the studio.
Mobile data networks
Most wireless telephone carriers offer some form of dedicated data delivery. Current third-generation (3G) wireless networks can use either of two systems � CDMA 2000 or UMTS. The current CDMA2000 version, called 1X EV-DO (Evolution-Data Optimized), can provide 154kb/s uplink and 2.5Mb/s downlink rates.
The Universal Mobile Telecommunications System (UMTS) is the successor to the second-generation GSM systems. Typically, UMTS uses the Wideband Code Division Multiple Access (W-CDMA) interface to provide mobile data services with rates currently available to 3.6Mb/s in the downlink.
You can see that the performance of the currently available mobile data networks can deliver data rates far below that of Wi-max, which is why companies see a significant market for higher-speed data options and have bid billions of dollars for the rights of the frequencies intended for the advanced wireless services.
In the future, wireless mobile telephone carriers will implement the fourth-generation (4G) technologies that will be primarily based on the Internet Protocol (IP), which will allow it to work with a number of existing and emerging technologies such as Wi-fi and Wi-max. The predicted data rates for 4G networks could be in excess of 1Gb/s and permit seamless roaming between different networks/technologies.
Equipment for remote broadcasting featuring wireless mobile data radios has been available for a few years. I am sure we will see exciting new remote applications that capitalize on these new network technologies, perhaps allowing a laptop to become a complete portable studio.
While not a wireless technology Really Simple Syndication (RSS) is considered a Web-feed format intended to deliver stored or real-time feeds to enabled Web browsers or delivered to an external MP3 device. The content can be a newsfeed, podcast or blog and could take the form of text, audio or video broadcast. When combined with existing and emerging wireless delivery methods, RSS will take on an increasing role in the broadcasting of information and other program content.
As a broadcaster, you should be thinking of new ways to exploit these technologies to enhance the listener experience, open new opportunities for revenue generation and perhaps save some money in the process.
McNamara is president of Applied Wireless, Cape Coral, FL.
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