3G Wireless Applications Need Better In-Building Coverage
by John Spindler, Vice President of Marketing
1/20/2006
convergedigest.com
Mobile wireless enterprise applications are a good way to increase productivity, improve customer service, and streamline business processes, but 3G mobile applications bring a unique challenge: ensuring adequate in-building coverage. Analysis shows that while only 35 to 40 percent of 2G (voice) traffic originates outside buildings, 70 to 75 percent of 3G (data) traffic originates inside buildings. And buildings are fairly unfriendly places for wireless signals, since they are constructed of steel, concrete, and other signal-defeating materials. The quality of mobile wireless coverage will determine the effectiveness of 3G mobile applications, so it’s important for coverage to be pervasive and provide high performance. Fortunately, it’s possible to extend wireless signals inside buildings with proven systems that make strong 3G mobile signals available anywhere.
3G Wireless Data Usage Trends
Wireless carriers in the U.S. are quickly rolling out 3G mobile coverage, and carriers in Europe and Asia are even farther ahead. Verizon and Sprint are using CDMA 1-X EV-DO and plan to cover half the country’s population by the end of March 2006, and Cingular, which only recently began its rollouts (albeit with higher-bandwidth HSPDA technology), is planning to catch up quickly with fast rollouts throughout 2006. According to In-Stat, WCDMA and CDMA 1-X EVDO subscribers topped 50 million by mid-2005, and that number is growing rapidly.
In Europe, UMTS is the high-speed standard, and Vodafone and others are already offering it there. In Asia, companies like NTT DoCoMo were the first to offer 3G mobile service. In China alone, In-Stat forecasts nearly 610 million mobile wireless subscribers by 2009, with up to 58 percent of them on 3G services.
3G mobile coverage makes good sense for carriers, who can charge a premium for high-bandwidth data plans. But it also promises to give businesses a competitive edge by enabling anytime, anywhere data access for mobile employees. Already, a number of mobile enterprise application vendors offer turnkey solutions for a broad range of applications, including CRM (sales order entries, tracking, quotes and price checks), ERP (inventory management, labor or materials usage), retail banking and brokerage services, shipment tracking, and logistics. Many large companies are even rolling their own custom applications for database access, expense reporting, and other tasks. So far, over 3,000 companies worldwide have deployed such mobile applications, including Bosch, British Airways, FedEx, Hyundai, and United Parcel Service.
This trend is being driven not only by carrier rollouts of 3G mobile coverage, but by the emergence of highly capable smartphones, which allow voice and data applications on the same device. The Blackberry mania that swept finance and other service industries for e-mail during the past few years is now expanding outward to Windows Mobile devices from Palm, Samsung, Motorola, Siemens, and others. As the number of devices increases, prices will come down, making them even more attractive for widespread business deployment in many departments.
In-building 3G wireless coverage challenges
In the race to deploy 3G mobile data coverage, carriers are primarily concerned with upgrading their existing outdoor network. While this will support applications in transportation, utilities, and construction industries, such coverage won’t easily support indoor mobile 3G wireless users. There are two basic challenges (see Figure 1):
Building materials dissipate wireless signals. Unless a carrier’s cell site is located directly outside the facility, the chances are that 3G mobile users will have to move toward the building’s windows to get a reasonable signal. As users move farther from windows (or work in areas without windows), the signal degrades to the point where applications either don’t work or are so slow they’re not worth using.
Outdoor cell sites can’t carry the load. Whether or not there’s an outdoor cell site nearby, that site was primarily designed to handle voice and light (e-mail and web) data traffic from outdoor users, not the data traffic from dozens or hundreds of users with enterprise applications inside a building. As these users access the cell site, overall bandwidth availability degrades and the coverage area shrinks for outdoor users as well as in-building users in the cell site’s coverage area.
Figure 1. In-building 3G mobile users can’t get good coverage from outdoor base stations.
In order for companies to rely on their 3G mobile applications, they need to ensure reliable, high-bandwidth service anywhere within their premises.
In-building wireless technologies
Fortunately, there are tried-and-true solutions for in-building cellular coverage that have been in use for years. Mobile wireless extension systems currently deliver reliable and pervasive coverage for cellular applications inside airports, stadiums, manufacturing facilities, hotels, and office towers.
In-building wireless extension gear includes a rooftop antenna (if necessary), a micro base station in the wiring closet or communications room, hubs on each floor (if needed), and distributed remote antennas to extend radio coverage. While in-building wireless systems are another layer of infrastructure for network managers to deal with, the good news is that the right system is very easy to manage, and the deployment costs are often shared with the wireless carrier as part of the incentive for signing a service contract.
There are two basic types of in-building systems: passive and active. Each system has its pros and cons.
Passive systems use few electronic components - these systems distribute signals to the remote antennas via rigid ½” to 7/8” coaxial cable (Figure 2).
Figure 2. A passive in-building wireless extension system.
The coaxial cable used to distribute radio signals in a passive system is inherently capable of supporting multiple carrier frequencies (although bandwidth is limited, so capacity may ultimately be a problem), and upgrading the system to support a new frequency can be as simple as adding the necessary radio frequency source.
On the other hand, the performance of passive systems is generally poor for applications requiring high capacity or bandwidth. Coaxial cable is both “lossy” (it’s like a garden hose – the longer the hose, the lower the water pressure – and similarly, the longer the coax cable runs, the weaker the wireless signal), and also noisy (noise can adversely affect the quality of wireless transmissions).
There is also an inverse relationship between capacity and coverage area with coaxial cable. When additional channels or another operator is added to the system, the coverage area of each antenna in the system may shrink, thus requiring a total redesign and reengineering of the system (which could be very costly). In addition, passive systems are usually more expensive to deploy. The rigid coaxial cable requires specialized expertise to install, and costs about $4.50 per foot to deploy compared with about $1 to $2 per foot for the Cat-5 Ethernet and fiber used in active systems. And installing large coax cable in ceilings can be extremely disruptive.
Finally, a passive system does not support remote diagnostics or alarming, so it doesn’t match the distributed management models of other networking gear. If a distributed antenna goes down, there’s no way for the system administrator to know about it until users start complaining.
Active systems use more electronics, feeding signals to distributed antennas from managed hubs on each floor of a building. Each hub can support up to 8 antennas (Figure 3.)
Figure 3. An active in-building wireless extension system.
In general, active systems, particularly those that use standard building cabling like fiber and Cat-5 Ethernet, offer better performance than passive systems. And for 3G data applications, performance is critical. These systems generally offer higher output power at the antenna, which translates into larger coverage area per antenna, and thus fewer antennas needed to cover a given area. Higher power also means that additional capacity can be added without having to reengineer the system. In addition, eliminating the use of coax cable eliminates much of the system noise, which results in better performance, particularly when transmitting from the mobile device to the network. Higher output power and lower system noise also means that the mobile device will have to use less power, thus increasing its battery life, a critical element to ensuring reliable wireless communications.
Active systems are less expensive to deploy. While passive systems are a “one size fits all” solution, active system electronics can be sized and priced to suit specific applications, from offices of less than 50,000 square feet up to airports encompassing millions of square feet. Also, as mentioned previously, active systems provide higher output power, so they require fewer antennas, resulting in lower deployment costs as they require less equipment and cabling.
In addition, active systems are fully manageable. The distributed hub architecture of an active system mirrors the design of Ethernet LANs – it is infinitely scalable and fully manageable. Active systems usually support SNMP alarms as well, so IT staff can monitor the status of all remote antennas using standard network management tools.
As we have seen, 3G mobile applications are becoming a key competitive strategy in many industries. Any company planning to deploy or improve mobile applications should consider in-building wireless extension an essential part of the solution. Fortunately, there are proven systems that can reliably deliver any carrier signal in any facility.
About the Author
John Spindler is Vice President of Marketing at LGC Wireless. John has more than 20 years of product management and marketing experience in the telecommunications industry. Prior to joining LGC, John held a number of product management positions within Nortel Networks, with job assignments spanning the areas of networking, network management, computer telephony integration and wireless technologies. He has also held positions with GTE and InteCom. John received his BA from U.C.L.A. and his MBA from U.S.C.
About LGC Wireless
LGC Wireless is a leading supplier of products for optimizing the deployment of metropolitan cellular,
PCS and 3G networks, and for providing mobile users with reliable in-building access to high quality voice and wireless data. LGC has shipped over 5,000 systems to more than 30 countries, and has provided wireless solutions in some of the world’s landmark properties–the Petronas Towers, the Bulring Shopping Centre, the Venetian Hotel, Denver International Airport, and the FCC headquarter building. Supported wireless access standards include TDMA, CDMA, CDMA2000, GSM, iDEN, 1xRTT, GPRS, Ev-DO, W-CDMA, and 802.11. LGC Wireless is ISO 9001 certified, ensuring that their quality management systems comply with international standards of excellence. |
