Test-drive the Push-To-Talk: First results and some features of the technology

July 29, Nokia and Beeline summed up in July last test operation of the Technology Push-To-Talk, which allows mobile phone as a walkie-talkie, but - with many additional amenities and features.

The service is Push-To-Talk («Push-to-talk") can very quickly - almost instantaneously - to communicate with one or several people simultaneously by pressing a button. Function must support the user terminal (handset) and the user must be included in the group. To send the message channels are used GPRS, which results in both advantages and disadvantages of the implementation of Push-To-Talk in mobile communication standard GSM.

During the month of service Push-To-Talk, implemented in the network BeeLine GSM »based network infrastructure, Nokia, has been tested by drivers of the company" Taxi Blues ", who used a Nokia 5140 phone that support the technology Push-To-Talk, in parallel with conventional radios. As testers were selected ordinary taxi drivers who have sufficient experience with car radios and, accordingly, can objectively evaluate the quality and convenience of the new service. Testing has proven that the technology is Push-To-Talk really works and is simple to use. During testing, the drivers mastered the Push-To-Talk for a few hours, after which this service is not less active than normal radio.

How it works

Push-To-Talk is not wasted constantly compared with the usual pocket radio walkie-talkie: as a radio station on the tube to press the button and "to air" a phrase or a short message. Members of the group / team will hear the message, and may in the same way to answer it. For transmission using GPRS-traffic, ie voice channels GSM network is not involved. Time "response" network GPRS, ie time interval from the moment you press the button and get the sponsor, "pee-pee", is about one-half seconds, and send a voice message (delay) - up to two seconds, although on busy networks, and under adverse circumstances, can reach up to several seconds . Push-To-Talk is based on the data network, but with some stretch to this service can be considered real-time voice communication. Unlike walkie-talkie radio stations can communicate with each other individually, and even their own (without an operator / manager) to build their own closed group communication.Interfere with the transmitted speech can not, you can only answer, in case of busy negotiating within a group of interlocutors are serviced by a network of queues in the order in which subscribers clicked a button on their handsets.

Service is implemented technology-based half-duplex communication VoIP (Voice over IP) using the protocols IETF, session transfer may be initiated immediately. Resources of the mobile network is used only for short periods of voice, and this transfer takes place not in short supply voice channels. At shemke clearly visible savings of network resources: the usual 10-minute conversation, "load" the network is three times larger than the typical intra-Push-To-Talk-communication within an hour. Each fragment is passed to speech is delivered directly to a dedicated Push-To-Talk server, which then sends the fragment to each recipient separately. Itself GSM / GPRS network does not control the transfer process point-to-multipoint, so that the service works transparently across the network GPRS. For speech coding is used codec AMR (5.15 Kb / s), well adapted to such specific defects, such as loss of frames.

Questions and answers

In discussing the results of testing the new service had many questions, but not all of them managed to get clear answers. We present some of the most interesting.

With the service charge - still no clarity in the BeeLine considered three possible options:

• · Pomegabaytnaya (for the amount of data transferred)
• Per minute (?)
• Without charging at all

With the tariffication of traffic all clear, but a "minute" probably had in mind every second - rounded up to the minute phrases 05/10/1915 seconds as something even unseemly. Lack of pricing is sure to be - as an attractive bonus or as part of a package for large corporate clients. Maybe give some free time, "flog" service to all customers, the benefit of tubes with such a functional until bit

Relatively small groups, comfortable, well-structured digitized snippets of speech, plus a log file with user names and time stamp (probably is) - the service downright specifically designed for centralized management of automated full backup of all negotiations with a record of all sent messages. What is called "full details of negotiations." Nokia representative politely, but carefully "translated the arrows on the operator. In the end, admitted "there is no" technical obstacles - but only just. Representatives for Beeline question was unexpected. In the end, agreed that, in principle, such a service can be arranged for large customers, but until the issue was not discussed.

Equipment certification - in the process. With regard to individual licensing of the service, then in theory it is within the existing licenses (including data transmission). However, in our wonderful country, every possible, and today there is a tendency for the licensing of individual services.

Software on other devices (with support for java) support Push-To-Talk can be realized, but with significant reservations.The problem is that in most cases java-application is not available the required level of network management functions on the phone. At present, information about such software implementations of Push-To-Talk not.

The compatibility of equipment and terminals from different manufacturers is expected to be resolved in early 2005 after the appearance of open standards. Nokia is in no way seeks to promote its "brand" is not compatible solution. Hopefully, the famous story of the confrontation Nokia Messaging and EMS will not be repeated.

Will Push-To-Talk used as a cheap alternative to long distance and international (and even local!) Mobile phone - it's hard to say. It all depends on the popularity of services and pricing. But the problem will clear - at least in Russia. Recall the famous five-second intervals protection, from which the operators are forced to give up (in the outgoing version) is largely due to the fans to arrange your free five-second "Push-To-Talk" on voice channels.

Experience first-hand

Demonstration during a press conference almost always looks convincing, but much more interesting to look at the work of service alive in a real environment. I managed (thanks to Beeline and "Taxi Blues") while riding as a passenger, to communicate with the driver and observe the work of Push-To-Talk "in a combat situation." Some impressions:

• Built-in speaker volume is sufficient - more than enough. So much so that most of the time tube is living in a holster or pocket, removed only for the time to reply / information.
• Voice sufficiently clear and legible, subjective voice quality is higher than that of automobile radios. Particularly well perceived female voice with a hateful "vizglivinkoy - explicit promising niche for the employment of beautiful ladies on the site controllers. Characteristic of "plugging" and deletions frames almost was not, perhaps once or twice, and even then not sure.
• One handset as a phone and radio in one package - an order of magnitude better. Out of the car snack car radio with them not potyanesh.
• "Mixtures" of several speakers at the same time does not happen, and it very well.
• During the reception / transmission, the display shows the number or name is passed - it is useful. Although it is for a taxi driver from the function a little bit confused, distracted by the display of arms.
• Very pleased with performance and services for hundreds of miles from Moscow, the radio networks to compete with operators cover GSM.

Summary

Conclusions until it is too early. The first experience of exploitation seems to be positive, but much depends on the rate of new terminals on the market and affordability of services. A huge plus Push-To-Talk - efficiency, intuitive and easy to use service. At one time, we noted the possibility of transmission of voice messages via MMS, but it enjoyed a few subscribers are primarily due to the concomitant zamorochek (slander / write, save, drive to MMS, send).While the Push-To-Talk is and will remain a big disadvantage: the subscriber out of coverage or switched off the phone message did not get it. Foreign manufacturers are positioning Push-To-Talk primarily as a dispatcher, a corporate decision, but the use of this service, student groups, with all parties and the teams seems to be quite promising. Especially if you can be yourself, "join" in this or that group.