Boosting the Network

How to increase capacity and keep your network up to speed for mobile shoppers

Like Formula 1 drivers and Olympic sprinters, wireless networks need speed and lots of it, especially now that m-commerce has suited up and joined the race.

To get the speed they need, providers will have to turn sluggish networks with limited capacity into streamlined, buffed-out systems. The solution may be as simple as replacing existing linear and omnidirectional antennas with smart antennas. Or it may mean supplementing a network with repeaters, an attractive alternative to costly network reconstruction. For some providers, implementing 3G sooner rather than later will be the key to crossing the finish line first.

Providers know that consumers who are eager to buy from mobile handsets won't stand for long waits or dropped connections. If m-commerce is to really win, providers must prepare the network first.

3G to the Rescue Third-generation solutions have promised to facilitate massive amounts of data at fantastic speeds, a crucial component to m-commerce. But the emerging workload could overwhelm existing networks already taxed by voice and other data flows - much of it at the snail's pace of 9.6kb/s.

Many in the industry agree that GPRS will revolutionize the market. As end customers' services become more and more mobile, demand will force the hand of new technologies such as EDGE, which could deliver data speeds of more than 400kb/s. Analysts say 3G will be key to offering anytime, anywhere commerce such as banking services, catalogue shopping and basic point-to-point purchasing.

Chris Smith, Alltel executive vice president of network services, said that to really answer the question of how to increase capacity on a wireless network, you must first understand the context in which m-commerce is used.

"M-commerce over WAP applications in the near term should not be very data intensive," Smith said. "In the CDMA networks today, the link is more robust than the data-transfer requirements."

Given this, Smith said the current delivery system for m-commerce works much the same as for voice traffic. As a CDMA provider that wants to increase capacity. Alltel's first option would be to add more providers to existing cells, Smith said. Alltel is among several providers exercising CDMA 1XRTT technology, designed to provide packet-data transmission at speeds of up to 144kb/s. Alltel also is looking to 1XRTT-EV, an enhancement to 1X, which will allow for bursting up to 2Mb/s, Smith said.

"To the extent that one airlink provides approximately 14.4kb/s, robust applications will result in increased transmission times," Smith said. "For CDMA, the evolution to 1XRTT will move the airlink from a circuit-switched nature to a packet architecture, allowing for multiple customers to share a much larger packet pipe. That will lead to significantly improved performance."

In June, Nortel Networks and Telstra announced that they had made cdma2000 1XRTT packet-data and voice calls on a live 800MHz CDMA network. Both companies saw the trial as proof that 3G would allow for increased network capacity and increase voice and data speed.

Based on Nortel Networks' CDMA Metro Cell base stations and advanced 1XRTT voice and data terminals from Samsung, the trial aimed to demonstrate a smooth evolution from Nortel's radio infrastructure to 3G networks.

"Integrated within the CDMA network, 1XRTT provides a range of enhancements including an improved platform for high-value wireless-data applications offering higher speeds, lower network costs as well as increased network capacity for voice calls," said Peter MacKinnon, Nortel vice president for wireless Internet strategic marketing.

Executives at Powertel said they anticipated the transition and are preparing to roll out Powertel's GSM packet-radio system that allows GSM providers to use spare capacity within the radio network.

"For example a 222 cell site is designed to support 24 Erlangs of voice traffic although 45 traffic channels are available," said Gowton Achaibar, Powertel vice president of engineering. "The 24 Erlang is driven by the need to maintain 1% blocking in a circuit-switched environment. With GPRS, the data packets will be transmitted in between voice calls and use the excess capacity available."

Coverage Vs. Capacity Some in the industry, however, fear that the introduction of capacity-rich networks could compromise coverage areas.

GPRS and EDGE is increasing data-transmission capacity of wireless networks many times over. But the latest technology also is putting greater demands on system equipment to ensure and maintain coverage and data transmission.

Claes Beckman, Allgon research manager, said the challenge is that higher transmission rates create completely different demands on systems. For example, the GPRS system requires a much-better-quality signal to perform at high transmission speeds. Improving the quality of the signal involves a reduction in the effective range of transmission, especially in built-up areas, which in practice causes a reduction in the size of cells.

That creates a risk of the whole network collapsing unless deliberate measures are taken to counteract this, Beckman said.

"The growing amount of data involved in new technologies causes greater demands on the handling of data via base stations," Beckman said. "Not only are more base stations required, but also better coverage solutions with more effective management of the traffic in existing systems. The need for flexible transmission solutions will also increase."

Some capacity and coverage solutions include using tower-top amplifiers, repeaters and distributed-antenna systems and filters to reduce interference. Allgon, like other vendors, implements a truncation-effective system by using repeaters, systems with dual-band antennas and combiners. This type of system makes it possible for several channels to use the same antenna.

With wireless-data transmission increasing in volume as a consequence of the 3G systems such as GPRS, EDGE and W-CDMA, new products are needed for more effective bandwidth usage, as are flexible solutions and co-existing systems such as smart antennas, linear-amplification stages, automatic tunable filters and distributed-antenna systems with integrated radio units, Beckman said.

Alternative systems such as wireless LAN and point-to-point systems like LMDS also are required.

Though increased data always will affect throughput, some providers aren't losing sleep over m-commerce's insatiable appetite for capacity. Powertel's Achaibar said although capacity issues are a concern, they will not be a significant problem until wireless audio and video content hits. Once consumer demand increases for downloadable movies and music, capacity is just a molehill and not a mountain.

"I expect network traffic to be driven up more by entertainment services and wideband applications yet to be defined," Achaibar said. "These will keep people longer on the network and in addition will utilize additional bandwidth."

Speeding Up 3G Roll-Out Will an m-commerce boom force providers to speed up their roll-out of 3G?

Achaibar said GSM networks will make the move to 3G through a natural evolutionary path. M-commerce may push providers to move down that path a little, but it will not be a huge leap.

"With GSM networks, operators have the luxury to move from GPRS to EDGE and then to 3G," he said.