Mobile VoIP applications can be used on your handsets (1)
Voip services have been used in the broad band worldwidely. It also makes the huge impact to the traditional telecom industry. Nowadays Voip providers have the next aim that is the field of the mobile procducts. The field of the mobile products has a big advandage comparing with the residential telecom services, so does mobile Voip services. The mobile Voip services not only bring more convenient but also offer lower price. Comparing with Voip services based on the broad band, the mobile Voip services have their own features and different implementations. Therefore mobile Voip services can be classified to several categories.
Accessed via WiFi and VoIP over celler data (3G) (VoCD)
From the fixed VoIP moving towards the mobile VoIP, the most straight forward approach is that replace the fixed broadband network with the WLAN. WiFi access normally can provide enough bandwidth for the requirement of VoIP, so the limitation of this approach is the computation power of the handset. In fact, Skype started to develop the PDA version long time ago. But as its audio compression algorithm requires a lot of computation power, the performance is not so good on PDA with lower processor. And the famous general VoIP client software — X-Lite/EyeBeam already has had PDA version for several years. So as long as the mobile handset supporting WiFi has a enough fast CPU and there are software clients on corresponding mobile OS, technically any VoIP provider supporting SIP can be used for mobile VoIP based on SIP. For example, the Nokia E70 has SIP option by default, which means no extra software needs to be installed to make VoIP calls. There are also WiFi mobile phones developed for the mobile VoIP based on WLAN that decreases the requirement for hardward with dedicated systems. But except the requirement for handsets, there are still two limitations. First, the coverage of WiFi is not as wide as GSM network that limits the mobility; Second, to mobile network operators, VoIP services reduce their profit seriously. To protect their own interest, mobile operators block the SIP port in WiFi networks their own and disable the SIP option on mobile phones bought from them.
Because of the limited coverage of WLAN, the VoIP over cellular data (3G) (VoCD) is presented. Anyhow, for VoIP over cellular data network, the bandwidth is still a problem. Before the GPRS becomes popular, the data communication capacity of mobile phones is quite poor. And the GPRS makes the data communication of mobile phones really usable. But for the VoIP application, the bandwidth of GPRS is not enough at all. Though the download speed of GPRS is just enough for VoIP, the upload speed of GPRS too slow for the VoIP which requires balanced bandwidth. Only when networks upgraded to 3G, the uplink data rate can reach 64kbit/s which is the minimum requirement of the VoIP. For example, the new Skype mobile phone seems to work with 3G network. Even the bandwidth of today’s cellular networks is increasing, these networks are fully controlled by mobile operators which means the approach is easier to be blocked than VoIP over WLAN. Other than these two approach, there are other solutions such as integrating VoIP gateway into the ADSL modem which may use bluetooth as wireless channel.
There are some main mobile VoIP products based on WiFi and VoCD.
Barablue: Support Windows Mobile phones and Nokia N/E series. There is still a windows PC version. When mobile phones support WiFi, the mobile VoIP option is valid and can talk with Skype, Google Talk as well as other Barablu users for free. The typical price to call normal phones in US is 0.01 USD per minute. Barablue also supports file transfer and vedio. If the handset doesn’t have WiFi, then you can only chat in text via GPRS or send SMS.
Fring: It may be the most famous product in this Category. Started from Symbian at beginning, now it also supports Windows Mobile platform. You can use Fring to make VoIP call in both WiFi and 3G network. Talk with Skype, Google Talk, MSN Messager, ICQ, SIP and other Fring users is free. Fring is not a VoIP provider, so you have to configure a Skypeout or a SIP account to call normal phones.
Truphone: I heard about Truphone and Fring around the same time, but Truphone seems to developed slower than Fring. Anyhow, Truphone itself is also a VoIP provide and Fring is just an application software. Truphone only support high end models of Nokia N/E series with WiFi feature (including N80ie upgraded from N80), though Truphone claims that it also works in 3G networks. Truphon only can talk and chat with Google talk and other Truphone users for free. New registered users have 2 USD/GBP free trial credit and till the end of this year Truphone users can call fixed lines (mobile lines in some regions) in more than 40 countries for free as well as unlimited free SMS.
Yeigo: AS a new company, there are fewer people knowning Yeigo than Fring and Truphone. However, it supports more or less same features as Fring (available on Symbian and Windows Mobile platforms; Yeigo can switch between WiFi and 3G networks; Yeigo can be used to chat with Google talk, MSN, Yahoo!, AIM, ICQ and other Yeigo users; users can send SMS all over the world with Yeigo; talk with other Yeigo users is free). On the same time, it provides its own VoIP service like Truphone (but 0.05 USD per minute to most popular destinations is not attractive).
There are still some others less known company that are developing similar products. But to catch up those market leaders, they need to provide more features to attract customers. There are also companys such as Globe7, which has already gained quite some market share, that are migrating their products to mobile platform. Maybe they will have better start points.
In general, except the difference of terminal devices and network medium, mobile VoIP products based on WiFi and 3G networks work in a similar way as VoIP services based on fixed network and the cost is also at same level.
Translated from 能在手机上使用的网络电话汇总（1）