Back a year ago I noticed that an incoming circuit-switched voice call during a 3.5G HSDPA packet-switched data session forced the packet connection to go back to 64 kbit/s dedicated bearer while the call was ongoing. After the call the bearer was upgraded to 384 kbit/s but was only put back on the High Speed … Continue reading HSDPA Alongside A CS Voice Call
With always on applications (think mobile eMail, IM, VoIP, etc.) on wireless devices, power consumption inevitably increases due to the constant exchange of TCP and UDP keep-alive messages to keep NAT firewalls open. Gone are the days in which wireless devices only communicated when there was really something to say. Pasi Eronen of the Nokia … Continue reading Nokia Research Center on Impact of Keep-Alive Messaging on Power Consumption
In the fixed line world, the basic Session Initiation Protocol (SIP) has become quite popular for offering voice telephony service. Lots of companies such as Vonage, Siptel and DSL providers are making use of it today. So why are we not using SIP in 3.5G and 4G networks as well? I guess there are both … Continue reading How To Extend SIP For Mobile Networks
I arrived in London yesterday and as I already have a prepaid SIM from 3UK, I used it for Internet access. Interestingly, just like in the Italy roaming scenario with the same SIM, data rates in the evening around London Victoria station were less than 300 kbit/s. A rather unpleasant experience as web pages were … Continue reading Is the 3UK Network Hopelessly Underdimensioned?
Since I travel a lot, I often stay in hotels. One thing in hotel rooms I could live without is the TV set, as I never have the desire nor the time to watch anything anyway. In recent years, however, I've noticed that good old cathode ray tube TV's are giving way to TFT TV's. … Continue reading Putting The Hotel TFT To Good Use
Today, we don’t think a great deal when we pick up a mobile phone to call somebody while in the car, or a train or moving otherwise. The network, if properly designed, ensures that the connection is handed over from cell to cell as we move. With most phones, this works rather well, probably because … Continue reading The Lost Mobility
This February at the Mobile World Congress, Intel invited me to experience their WiMAX network that they had set up in the city during the event. Of course I had lots of technical questions and one of them was on the backhaul equipment they used to connect the base stations to the network. I was … Continue reading Microwave Backhaul
This week I’ve been taking a closer look at how LTE networks will be used in practice. One of the big differences to current 3G and 3.5G networks is that LTE is fully based on IP, i.e. there is no longer a circuit switched core network for voice telephony. Today, it makes sense for 3G/3.5G … Continue reading The Packet Call Becomes History with LTE
While at last years show HSPA functionality was not to be found on handsets except for the very high end mobile phones such as the N95, 3.5G connectivity has made it to mainstream handsets this year. A good example is the very small and light Sony-Ericssons K660 phone which is definitely targeted at the mass … Continue reading 3GSM / MWC : HSPA is Mainstream Now
Bad news for all of those who keep telling people that wireless broadband can’t compete with DSL and cable because networks couldn’t cope with the traffic: You are wrong! Arthur D. Little consulting published a study last week that last year 57% of new broadband connections were wireless (3.5G + WiMAX a bit I guess) … Continue reading Wireless Now Accounts For A Third Of Austria’s Broadband Connections