Technological Approaches | Wireless Local Loop

Wireless local loop technology falls into four general categories: analog cellular, digital cellular, proprietary fixed wireless, and cordless telecommunications.

First-generation wireless local loops are based on analog cellular technologies, which have a solid track record of performance, support a relatively wide coverage area, and provide economies of scale for infrastructure and handsets. The key drawback with analog cellular is that it is optimized for mobility rather than local loop service; since user bit rates are low, wireline voice quality is elusive.

Digital cellular offers greater capacity and better voice quality than analog cellular, but it too is geared toward mobile applications. Coverage areas are usually smaller than with analog and there is a profusion of industry standards. Even when there is general agreement on standards—as there is with GSM, for example—the frequencies over which it operates may differ from country to country.

Proprietary systems—such Nortel's Proximity I Series—are designed from the start as alternatives to the copper-based local loop. They operate at higher frequencies, usually 3.5 GHz or above, where the spectrum is less crowded. They provide high-quality voice at 32 Kbps via Adaptive Differential Pulse Code Modulation (ADPCM)—versus 8 Kbps or 13 Kbps used in most WLL systems—and support voice-band data modems and high-speed fax transmission at up to 28.8 Kbps. These systems are interoperable with the PSTN and are aimed at new operators in competitive markets, where the challenger must be able to match the advanced service offerings of the wired incumbent to have any chance of success. The key disadvantage with these proprietary approaches is that they do not usually support mobility.

Some WLL systems make use of the standardized cordless telecommunications systems—including CT2, DECT, PACS, and PHS. While all are well suited for deployment in dense urban areas, and offer higher quality voice at 32 Kbps and data services up to 28.8 Kbps, each has its strong points. CT2 (Cordless Telephone Two) makes a good pair-gain system for countries with an existing, but insufficient, feeder network infrastructure. DECT (Digital Enhanced Cordless Telecommunications) is a proven technology widely used in Europe in wireless PBX implementations, while PHS (Personal Handyphone System) has been successful in Japan and is headed toward becoming a pan-Asian standard.

PHS offers high-quality, low-cost mobile telephone services using a fully digital system operating in the 1.9-GHz spectrum. Originally developed by NTT, the Japanese telecommunications giant, PHS is based on GSM technology. In addition to personal communications, PHS is being used in wireless PBX and wireless local loop applications.

PACS (Personal Access Communications System) is based on Bellcore's Wireless Access Communications System (WACS) and on Japan's PHS. Operating in the 1.9-GHz licensed PCS band, PACS provides an approach to PCS that is fully compatible with the local exchange telephone network and interoperable with existing cellular systems. PACS supports mobility better than the other standards—at vehicular speeds at over 65 miles per hour—and it also can be used for pedestrian venues, commuting routes, and indoor wireless. Although some vendors are now getting behind PACS in the United States, they face an uphill battle for market acceptance, if only because they got off to a late start—the major service providers having already committed to their WLL strategies.

All of these technologies work well enough and the costs are very attractive. In fact, WLL technology is now far more economical than copper-based local loops. Wireline local loops now cost anywhere from $1000 to $2000 per subscriber to provision, depending on the distance of the subscriber to the central office switch, while wireless local loops are down to about $500 per subscriber, regardless of the distance of the subscriber to the local switch.

Types of ACDs | Call Center Technology

ACDs can be a part of your PBX software, based in a separate PC (called a switchless or software-based ACD) and attached to a phone system, or stand-alone, meaning a switching capability is built into the system and it processes calls by itself.

Standalone ACD systems are sometimes known as ACD/PBXs, because they combine ACD call handling with the functions of a PBX. If your company is primarily a sales office or you plan to make money providing call center services, this kind of system might be better for you than a PBX by itself. Adding ACD software to an existing key system or PBX later might be more expensive than buying an ACD/PBX combination initially.

Virtual ACDs give you ACD features, but require no customer premises equipment. Your incoming calls are processed outside your facility and you pay for usage only, typically between 20 to 25 cents per minute.

PC-or server-based systems are aimed at under-400 person call centers that have significant data requirements. Comms server-based ACDs are easier to interface to information databases because they’re PC-based and can communicate digitally with other computers.

Call Center Technology

Call Centers, Automatic Call Distribution (ACD), and Predictive Dialers

A call center is a group of people, called agents, who, with their associated phone and computer equipment, do the same, repetitive, type of work.

Inbound call centers handle incoming calls (and faxes, email, and queries from Web sites), and outbound call centers make outgoing calls, usually telemarketing or research-related.

Inbound Call Centers and ACD

Most traditional call centers handle inbound voice calls. Special software and software/hardware combinations for call centers called Automatic Call Distributors (ACDs) distribute these calls to agents that can handle them using any of a number of call allocation and distribution schemes.

An ACD does two things. It minimizes the amount of time that a customer spends waiting to be helped, and it maximizes the amount of time that agents spend interacting with customers.

ACD systems are becoming more sophisticated and are competitively priced. Even small businesses can enjoy the benefits of logical distribution and management of inbound calls.

Once a call arrives at an ACD, sometimes directly from the outside telephone network, sometimes from the internal phone system or IVR (Interactive Voice Response) system, the ACD distributes the call to whoever is available in the group that is handling those particular calls.

The ACD system decides which phone will ring next and puts overflow calls into a holding pattern until someone is available. This holding pattern (or queue) keeps track of the order of the callers, plays music-on-hold and can play update greetings for the callers. Update greetings assure the caller that he has not been forgotten or can give him the option to leave a voicemail message instead of continuing to wait.

Some ACD systems can inform the caller of the average wait time in the queue or update them whenever their position in the queue changes. This feature lets the callers to judge whether or not they want to continue holding and puts them more in control of the situation.

A small office can use an ACD system to evenly distribute calls from prospective clients to sales representatives or to balance the incoming call load between all employees (or a designated group) in the office to ensure that all calls get answered immediately.

You could configure your ACD system to distribute all incoming calls to all employees, for instance, only if the receptionist (if you have one) is on another call.

Some systems can send the customer’s data file with the voice call, so the file reaches the agent’s computer as the call reaches her headset. Some ACD packages let callers punch in a phone number at which they wish to be called back, hold their place in the queue, then automatically call them back when an agent is available.

An ACD integrated with the Internet displays a button on the associated Web page. When a caller clicks on the icon, they’re usually given a screen-based form to fill out. The customer can request an immediate callback from an agent or a callback at a later time.

Internet applications with video capability are available on ACD systems, usually larger systems, and they require the customer to have a video camera attached to his computer. Video technology that provides fairly respectable smoothness of motion is possible at 128 Kbps (two channels of a BRI ISDN line). Internet-enabled agents can push Web pages to callers and/or use text chat.

Agent Callback lets an agent flag calls, and the system uses ANI (Automatic Number Identification) so if a caller dials back within a set period the same agent can receive the call.