Application

VoWiFi: the next big thing?

The next big thing may be the merger of Wi-Fi and VoIP, muses Kusum Makhija.

VoIP in particular and Internet telephony in general have come a long way from their inception. Most recently, the next big thing has been to merge WiFi with VoIP. VoWiFi or Voice over Wireless Fidelity simply means a WiFi based VoIP service—or to put it in another way, a wireless VoIP system.

Whereas VoIP consists of the hardware and software that enables people to use the Internet as a transmission medium to make calls, VoWiFi is the wireless version of this technology that is designed to work on wireless devices such as a laptop or PDA. Along with the added benefits that it brings to businesses and to those with a need for wireless communication, VoWiFi opens up the door for a whole new market of consumer products such as a standalone VoWiFi handheld.

Says Dinesh Sehgal, National Marketing Manager, Convergence Solutions, Avaya Global Connect, “We have products with software capability to converge IPBX with wireless capability that is seamlessly inter-operable. These are deployed by large enterprises with a robust IP network in place.” The company is working closely with Nokia to provide a converged solution that has GSM, VoWiFi and IPBX integrated into a single solution.

Says Protip Ghose, Head, Office of Technology, Networks, Motorola (India), “Voice and data can be transmitted over the WiFi in the same way as a LAN. However, as this is wireless there is some degree of mobility. Systems are also available for handover between cellular and WiFi.”

Motorola has cellular-to-WiFi seamless mobility solutions and a number of dual-mode phones. Discussions are on with different carriers to adopt these technologies.

Untethered workers

With delicencing taking place in India, VoWiFi has the potential to take off in a big way Mathew Varghese Consulting Systems Engineer Cisco

WiFi increases productivity by freeing workers from their wired network connections; VoWiFi completes the process of untethering workers from their desks by offering mobile access integrated with the enterprise telephone network—something a traditional cellular service cannot do. With more reliable coverage indoors and higher voice quality than traditional cellular systems, one of the biggest benefits VoWiFi has is cost; using cellular to achieve mobility within the enterprise is an expensive proposition.

Sehgal agrees. “The productivity enhancement from VoWiFi depends largely on how and to what extent a company can extract benefits from it. The cost of handsets may affect a company’s ROI initially, but in the long run it results in a productivity boost.”

A key consideration when designing a WiFi network, with or without voice, is which radio frequency technology to use. Today there are three different standards, each with different data rates. The most popular is 802.11b, which operates in the 2.4 GHz spectrum, supporting up to 11 Mbps per channel and up to three non-overlapping channels. 802.11g also operates in the 2.4 GHz spectrum and supports three non-overlapping channels; it supports a data rate of up to 54 Mbps. 802.11a operates in the 5 GHz spectrum, and supports a data rate of up to 54 Mbps and 23 non-overlapping channels. Most VoIP handsets in the market today are manufactured for 802.11b due to its popularity.

However, in order to support high-quality voice, the capacity of a WiFi network needs to be taken into consideration. As more access points are installed, the possibility for co-channel interference rises. The more non-overlapping channels that can be configured, the greater the extent to which this risk can be lessened. Since 802.11a supports more non-overlapping channels, it is a good choice for high-density environments.

Notes Mathew Varghese, Consulting Systems Engineer, Cisco, “With delicencing taking place in India, VoWiFi has the potential to take off in a big way. This is despite the fact that it can operate only within a closed user group...the base is widening as enterprises are increasingly deploying VoIP.”

Broad coverage is the key to making VoWiFi a truly viable application. Fortunately, in addition to cellular-to-WiFi roaming, there are other up-and-coming technologies that can be used to extend the reach of a wireless network.

There have already been a number of well-publicised VoWiFi deployments in industries such as healthcare, manufacturing and education. These industries have been early adopters of the technology because it solves some of the unique challenges they face such as the need for reliable mobile communication over large campuses. Now, with standards maturing and handset prices dropping, VoWiFi is poised to move from the ranks of early adopters to the mass market where enterprises of all shapes and sizes begin to make use of this technology.

Roaming challenges

One of the biggest challenges with regard to VoWiFi is roaming access. A WiFi access point offers a communication range of up to 90 metres (commonly called a hotspot). Continuous conversations require that a caller stay within an area of overlapping hotspots unless the caller has a VoWiFi dual-mode phone that switches to cellular transmission when the caller moves out of a hotspot.

People are paying close attention to communicating through VoIP over WiFi. Cellular companies are not feeling threatened yet due to some serious problems facing VoWiFi such as roaming access and security. Admittedly, making VoIP calls over WiFi will be an adventure for several years. As 3G proponents are happy to point out, the 802.11 WiFi standards are not designed to handle voice. This quarter, however, should see the finalisation of the standard’s wireless multimedia extensions, which tag different types of traffic with various priority levels. Manufacturers of WiFi chipsets must also fix a more basic problem: battery power. When WiFi is enabled for voice, it drains huge amounts of power in order to detect or listen for incoming calls. Because cell phones were designed from the start to listen for calls, they are far more power-efficient. WiFi chipset and device vendors are working on the improved sleep modes to conserve energy.

If you can take the same cell phone you use at work on the road and even link it up to your home WiFi network to make cheap phone calls, why not cut the cord altogether?

kusum@expresscomputeronline.com