Great idea but is VOICE OVER WLAN using Wifi better than Femtocells– our take on a 6 month test of T-mobile Hot Spot @ Home September 2008
The bottom line now: Voice over wireless LAN using WiFi does NOT work but it might in the future.
We think the Femtocell concept may be a better solution to More indoor bars in more places in your home, office or apartment.
The Dual-mode phones sold by T-mobile for Hotspot@ home SUCK. VoWLAN MIGHT work in home and small office or car dealer environment. Why we tested but we sold our retail car delaer and converted to developing data for car dealers
tested
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The vision ...A dual-mode phone can switch from the outdoor cellular network to the WiFi /WLAN network. This is an example of what is sometimes called fixed-mobile convergence. Voice-over-WLAN (VoWLAN) is GREAT idea. We agree it will grow in business environments, like a car dealer. Our employees were VERY mobile. In our work environment as well as at our home everyone wants to communicate, this means to make voice calls, send and receieve email and text and access data from the same handset. Nobody want to carry more than 1 handset. We hope handsets than can have more than 1 number will evolve.Are there any GSM handsets that allow for multiple SIM cards?
To make VoWLAN work in many houses will depend on overcoming challenges that did not exist in the pre-voice Wi-Fi era.
Tried all of this but failed
These challenges are related to the traditional cell-planned architecture of wireless systems. For most houses even with multiple access point each AP transmits on one of the three non-overlapping channels available in the 802.11b/g standard. When installed access points should be carefully positioned and “tuned”. This is to decrease co-channel interference that can kill transmissions. Most consumers do not know what channel their router is set to let alone how to change channels
Enterprise-class systems are either optimized for coverage (wireless signal is available everywhere in the enterprise, but not with optimal bandwidth) or capacity (a maximum number of users can have optimal bandwidth, but not everywhere in the enterprise), but rarely for both. Most systems do not address the real challenges of VoWLAN–that voice communications demand mobility and a reliable wireless connection.
The interplay between WiFi a standard developed for asynchronous data transmission and voice technology that depends on regular, synchronous communication will always be complex. Below are our experiences setting a home Wi-Fi voice network (VoWLAN deployment).
Wireless Voice meaning moving.
This, combined with traditional WLAN systems that organize access points in a cellular pattern, yields networks that are not optimized for mobility. The basic problem revolves around the “handoff,” which is what happens as users move through cell-planned WLANs, losing the link from one AP and associating to another as they move. The delay introduced by handoff is usually not a problem for data transmissions but is often a deal-breaker for voice calls.
Range of a WiFi signal will vary GREATLY. Another voice reality is its need for a constant, stable connection rate. In traditional WLANs, the negative impact of such things as rate adaptation, edge users, coverage holes and interference are not as strongly felt, since data communication, bursty by nature, can tolerate the widely varying data transmission rates that result from these effects. Voice performance, however, will suffer in such an environment, but the cell-based WLAN has no solution to this challenge.
Voice and data do not mix well. Convergence means adding voice to data–but these two traffic types clash. WLANs have been data-centric and, even with the advent of new standards, still have inefficient quality-of-service (QoS) mechanisms for prioritizing voice over data traffic. Effective QoS needs to be based on deterministic methods, otherwise the co-existence between converged voice and data will be uneasy at best and unworkable at worst.
An alternative approach to cell-based systems has been to allow all access points (APs) in the network to transmit and receive on the same channel, creating a “channel blanket” from the aggregate coverage of the APs.
The channel blanket eliminates the problems associated with supporting the mobile user, particularly the issues of handoff, reliable and stable connections, and QoS. The ease of deployment and maintenance of such systems, compared to more complex cell-based topologies, is an additional benefit of this architecture, since the RF cell planning of traditional systems is eliminated.
Dave Ahl’s house is a practical demonstration of how WiFi signal has been used please solution please