Showing posts with label Android. Show all posts
Showing posts with label Android. Show all posts

Thursday 11 November 2021

Network Slicing using User Equipment Route Selection Policy (URSP)

Google announced that its latest smartphone OS will include support for 5G network slicing. Last week Telecom TV brought this news to my attention. The article explains:

It's a move designed to leverage its expertise in devices in order to give it the edge over its rival hyperscalers.

It comes in two flavours. The first is for enterprise-owned handsets, and routes all data sent and received by a device over the network slices provided by that company's mobile operator. Android 12 gives operators the ability to manage slices using a new dynamic policy control mechanism called User Equipment Route Selection Policy (URSP). URSP enables devices to automatically switch between different network slices according to which application they are using. For example, someone working for a financial institution might require a highly-secure network slice for sending and receiving sensitive corporate data, but will then require a reliable, high-throughput, low-latency slice so they can participate in a video meeting.

The second flavour is implemented in the work profile. For years, enterprises have had the option of creating work profiles on Android devices – irrespective of whether they are owned by the organisation or the individual – to use as a separate repository for enterprise apps and data. When Android 12 comes out next year, enterprises will be able to route data to and from that repository over a network slice.

Google said it has already carried out network slicing tests with both Ericsson and Nokia using test versions of its recently released Pixel 6 smartphone running on the as-yet-unreleased Android 12 OS.

Last week Taiwanese operator Far EasTone (FET) and Ericsson announced they have completed the world’s first proof of concept (PoC) for simultaneously connecting multiple network slices per device running on Android 12 commercial release. The press release said:

The trial, carried out on FET’s 5G standalone (SA) infrastructure built on Ericsson’s radio access network and cloud-native Core network, successfully demonstrated the 5G user equipment slicing policy feature (User Equipment Route Selection Policy, or URSP) on multiple Android devices. This marks a breakthrough in network slicing capabilities on a 5G standalone network and paves the way for further ecosystem development in this important area.

With more 5G networks evolving to standalone architecture around the globe, end-to-end network slicing, which includes Ericsson RAN Slicing to secure Quality of Service (QoS) differentiation, plays a key role in enabling new services for end users, with which multiple virtual 5G networks are created on top of one physical network. The 5G trial, in collaboration with FET, Ericsson and Android, went even further in network slicing capabilities by introducing and demonstrating 5G user equipment (UE) slicing policy (URSP) features that allow devices to simultaneously operate on dynamic policy control and selection between multiple 5G network slices. This enables the steering of applications and services with specific requirements to defined slices without switching devices.

Multiple slices allow devices to have multiple profiles to secure different levels of experience, security, and privacy requirements, based on the needs of the different applications and in correspondence with the user profile.  For instance, a device can have a personal profile with private data from apps or off-work entertainment, and a work profile with enterprises productivity apps. With URSP features, employers can customize the work profile with increased security and enable better use of RAN Slicing with QoS so that enterprise-related apps can work even during network congestion.

Some security-sensitive apps, such as mobile banking, can also benefit from different routing mechanisms of the traffic enabled by URSP. For instance, the banking app would not need to send its traffic to the internet and then to the app server as it does today. Instead, it could go straight to the app server and avoid the routing through internet. With the shortest route by connecting to a defined slice, users could reduce the risk of being attacked by hackers.

In their technical whitepaper on Network Slicing, Samsung explains: 

Along with the concept of network slicing and features in the RAN and Core network, UE Route Selection Policy (URSP) is introduced as a way to manage network slice information for the UE. URSP is a network slice feature enabled by the PCF which informs the network slice status to the UE via the AMF. In 4G network systems, it was near impossible to install new services in the network for a UE. But through the URSP feature, 5G network operators can easily configure new service for a UE. Figure 12 (top of this blog post) shows the difference in network slice selection in 4G and 5G Network. In 5G network, slice selection policy can be configured dynamically through URSP, while slice selection policy is pre-defined and cannot be changed dynamically in 4G network.

URSP contains OSId, AppId, IP descriptors to define the application and Single-Network Slice Selection Assistance Information (S-NSSAI), Data Network Name (DNN), Session and Service Continuity (SSC) mode information for the application and network slice mapping.

The S-NSSAI identifies each network slice service and provides information to properly assign network slice/functions. An S-NSSAI is comprised of:

  • A Slice/Service type (SST), which refers to the expected network slice behavior in terms of features and services;
  • A Slice Differentiator (SD), which is an optional information that complements the Slice/Service type(s) to differentiate amongst multiple network slices of the same Slice/Service type.

3GPP allows the use of the Slice Differentiator (SD) field that can build customized network slices. The SD field can be used to describe services, customer information and priority.

Here is a short video from Mpirical explaining 5G UE Route Selection.

It it worth reminding here that this feature, like many of the other 5G features, is dependent on 5G Core. We hope that the transition to 5G Standalone Networks happens as soon as possible.

Related Posts:

Tuesday 4 December 2018

Can KaiOS accelerate the transition from 2G / 3G to 4G?


The GSMA Mobile Economy 2018 report forecasts that 2G will still be around in 2025 and the dominant technology will be 3G in Africa. GSMA Intelligence Global Mobile Trends highlighted similar numbers but North Africa was missing in that report. As you can see in the picture below, 3G devices will make up 62% of the total number of devices in Sub-Saharan Africa and 37% in MENA.

Similar information was provided by Navindran Naidoo, Executive, Network Planning & Design, MTN Group in TIP Summit 2017 and Babak Fouladi, Technology and Information System (Group CTIO) , MTN Group in TIP Summit 2018. In fact Babak had a slide that showed 3G devices would make up 61%  of total devices in 2025 in Africa. Rob Shuter, Group President and CEO, MTN Group said at AfricaCom 2018 that Africa lags 7 years behind the Western countries in mobile technologies. Though this may not be universally true, its nevertheless a fact in many areas of the Continent as can be seen from the stats.

In my blog post "2G / 3G Switch Off: A Tale of Two Worlds", I said operators in many developing countries that maybe forced to switch off a technology would rather switch 3G off as they have a big base of 2G users and 3G devices can always fall back on 2G.

So what are the main reasons so many users are still on 2G devices or feature phones? Here are some that I can think off the top of my head:
  • Hand-me-downs
  • Cheap and affordable
  • Given as a gift (generally because its cheap and affordable)
  • 2G has better coverage than 3G and 4G in many parts of the world
  • Second/Third device, used as backup for voice calls
  • Most importantly - battery can last for a long time
This last point is important for many people across different parts of the world. In many developing countries electricity is at a premium. Many villages don't have electricity and people have to take a trip to a market or another village to get their phones charged. This is an expensive process. (Interesting article on this here and here). In developed countries, many schools do not allow smartphones. In many cases, the kids have a smartphone switched off in their bag or left at home. For parents to keep in touch, these kids usually have a feature phone too. 

While all feature phones that were available until couple of years ago were 2G phones, things have been changing recently. In an earlier tweet I mentioned that Reliance Jio has become a world leader in feature phones:


I also wrote about Jio phone 2 launch, which is still selling very well. So what is common between Jio phones and Nokia 8110 4G, a.k.a. Banana phone

They both use a new mobile operating system called KaiOS. So what is KaiOS?

KaiOS originates from the Firefox OS open-source project which started in 2011 and has continued independently from Mozilla since 2016. Today, KaiOS is a web-based operating system that enables a new category of lite phones and other IoT devices that require limited memory, while still offering a rich user experience through leading apps and services. KaiOS is a US-based company with additional offices in France, Germany, Taiwan, India, Brazil, Hong Kong, and mainland China. You can find a list of KaiOS powered devices here. In fact you can see the specifications of all the initial devices using KaiOS here.

Here is a video that explains why we need KaiOS:



There are couple of really good blog posts by Sebastien Codeville, CEO of KaiOS:

There is so much information in both these articles that I will have to copy and paste the entire articles to do them justice. Instead, I want to embed the presentation that Sebastien delivered at AfricaCom below:



I like the term 'smart feature phone' to distinguish between the smartphones and old dumb feature phones.

Finally, it should be mentioned that some phone manufacturers are using older version of Android to create a feature phone. One such phone is "Reinvent iMi" that is being billed as 'Slimmest Smart 3G Feature Phone' in India. It uses Android 4.1. See details here. Would love to find out more about its battery life in practice.

My only small concern is about security of old Android OS. As Android is extensively used, new vulnerabilities keep getting discovered all the time. Google patches them in newer versions of the software or sometimes releases a separate patch. All updates to the Android OS stops after 3 years. This means that older versions of Android can be hacked quite easily. See here for example.

Anyway, feature phones or 'smart feature phones' are here to stay. Better on 4G than on 2G.

Monday 25 June 2018

Free Apps for Field Testing - Part 2

The last time I wrote about the free apps for field testing, many people came back and suggested additional apps that are much more commonly used. In fact we got the following comment when 3G4G re-posted this

As I have used both these apps frequently, here is a small summary on them.

Network Signal Guru: This is surprisingly very popular and is quite useful. The only issue is that you need to have a rooted phone with Qualcomm chipset. I know many testers have their favourite phones and quite a few testers buy the latest phones, root them and start testing using NSG (Network Signal Guru).

I prefer using Motorola Moto Gx series phones. They are cheap, not too difficult to root (YouTube have quite a few tutorials and Google search works too) and I find that their receivers are better than others. Have detected cells that other phones cant and have even camped and speed tested on them too.

So what can NSG do?

It can provide lots of useful information on the physical layer, cell configurations, neighbor cell lists, MIMO, etc.
You can even RAT lock to LTE / WCDMA / GSM and band lock to use a specific band. It can be very useful during surveys when you want to check if you can see particular frequency anywhere in an area. You can also see Codecs, RACH information, Data information, etc.

Finally, one of the best things I find is the signalling information. Some of the details are only available for purchased option, its nevertheless very useful. Just in case you are wondering how much does it cost, its roughly £50 per month license in UK.


Cell Mapper: I find this much more helpful as it can be used without rooting. CellMapper is a crowd-sourced cellular tower and coverage mapping service. Its simple and only used for basic testing but nevertheless very useful. To give you an idea, the other day I was camped on a cell with very good signal quality but very poor data rates and there weren't many people so congestion didn't seem like a factor. On investigation I found out that I was camped on 800MHz band that has limited bandwidth per operator and there was no CA.

Cell mapper, as you can see provides information about the cell you are camped on, the cell tower location, what other sectors and frequencies are there, etc.


Do you have a favorite testing app that I missed? Let me know in comments.

Saturday 10 December 2016

Free Apps for Field Testing

People who follow me on Twitter may have often noticed I put photos when I am doing surveys, field testing, debugging, etc. In the good old days we often had to carry a lot of different kind of specialised test equipment to do basic measurements. Nowadays a lot of these can be done with the help of free apps on Android phones. The best tool that can provide a great amount of info is Qualcomm's QXDM but its really expensive.

Here are a few tools that I use. If you have one that I havent listed below, please add it in comments.


The screen shot shows the main tools along with my favourite, SpeedTest. While I agree that Speedtest is not the most reliable approach to speed of your connection, I think its the most standard one being used.


WiFi Analyzer is another great app that can be used at home and other locations where people complain about not getting good WiFi speeds. I have been at locations where the 2.4GHz is absolutely packed with APs. 5GHz is also getting busier, though there are still a lot of free channels.


G-NetTrack Lite is a great tool to keep track of the cells you have been visiting. In case you are driving this can collect a lot of valuable info. The paid version, G-NetTrack Pro can collect the info in form of a map that can be used for offline viewing with the help of Google Earth.


I use LTE Discovery mainly for finding the band I am currently camped on. It would be great if a tool can give the exact frequency and earfcn but the band is good enough too. I was once in a situation where I could see two different cells but they had the same PCI. Only after using this, I figured out they were on different bands.


Finally, Network Cell Info Lite gives neighbour cells which can often be useful. I am not sure of these are the neighbours from System Info or from Measurement Control messages sent by network or just something like Detected cells that the phone sees around.

Pind and IPConfig are other tools that can come handy sometimes.

Are there any other tools that you like? Please share using comments.

Free Apps for Field Testing - Part 2

Saturday 1 March 2014

Mobile, Context and Discovery - Ben Evans


An Interesting presentation and Video from Benedict Evans, both embedded below:



There is an interesting Q&A at the end of the talk in the video. You can directly jump to 27:30 marker for the Q&A. One of the interesting points highlighted by him, that I always knew but was not able to convey it across is there is no real point comparing Google and Apple. I am too lazy to type down so please jump to 45:10. One of the comment on the Youtube summarises it well:

"Google is a vast machine learning engine... and it spent 10-15 years building that learning engine and feeding it data"

So true. It is not Apple vs Google; it is not about the present. It is about the future (see Google's recent acquisitions for context). As Benedict says, if Google creates beautiful, meaningful and unique experiences for users, why would they do it only for Android, they would also have it on Apple devices. 

In the end, comparing Apple and Google is like comparing Apple(s) and Oranges :)



Tuesday 29 November 2011

Nice Pie Chart on different Android Devices

Click to enlarge

I guess Pie charts like these can convey more information then writing about the percentages of devices sold. Maybe we should use them more often to represent information.

Source: From a presentation by Deutsche Bank in the 4th LTE North America Conference, 8 - 9 November 2011, Dallas, Texas, USA

Wednesday 25 August 2010

Phone(y) Detectives!


Too many Apps are being developed that will turn people into ametuer detectives.

A new mobile application called Recognizr can identify a person’s face via your phone camera and deliver not only profile information about that person but also show you their latest status updates.

Swedish computer vision specialists Polar Rose combined forces with interface designers TAT (The Astonishing Tribe) to create the Recognizr as a prototype application for Android phones to show off Polar Rose’s mobile face recognition library. Polar Rose’s software recognizes individuals, while TAT’s interface uses augmented reality to show profile information from sites like Facebook, YouTube and LinkedIn and the latest status updates from the recognized person.

Recognizr uses FaceLib, a mobile face recognition library from Polar Rose, which is available for Android and iPhone. FaceLib can recognize faces in photo or video but, in common with other facial recognition products, is more accurate for photos. Recognizr also uses Polar Rose’s server-side solution FaceCloud because you can’t store profiles of all potential matches in the phone — although recognizing people who are already in the phone’s address book can be handled locally on the device.

In a presentation at the Hot Chips conference at Stanford University, David Petrou, a project lead of Google Goggles, described the future of Goggles.

Google Goggles, as Petrou reminded the audience, includes the ability for the mobile Android application to take a picture of the object ad send it back to Google's cloud services. Petrou demonstrated the app with a picture of a beer can with an Android smart phone, which identified the can as a can of Boddington's. A results page showed an icon of the result, with some results from the Web. He also showed a videocassette of the movie Breakin', and Goggles identified it correctly.

The basic design principle of Goggles, Petrou said, was that it has to be universal: queries can't be processed within a single finite context, such as a bottle of wine. Petrou showed off a book that contained an image of a manual transmission linkage: Goggle returned both a link to the book on a shopping site, but also linked to a search on manual transmissions.

Goggles returns a specific result about a third of the time, Petrou said, and the internal CONGAS recognition engine matches images to aa database of about 150,000 landmarks by finding "interest points" within an image. New photos compared to the database can be correctly identified about 50 to 60 percent of the time, with a false positive rate of about one in 10,000, he said.

Goggles' strong suits? Packaged goods, such as movies. But with generic objects, such as an image of a red car, Goggles still struggles.

Goggles can also work with bar codes. A recent addition has been the inclusion of machine translation, which can recognize text and translate it on the fly.

Unfortunately, Goggles has to work as a client application, as Google needs as much of a fine-grained control of the camera as possible, such as the white balance.

Petrou said that Google was considering opening up Goggles to third-party applications, so that a stamp collector could upload an image of a stamp with annotation describing what it is. An open API may also be released, so that a picture could be taken of a foreign currency, and an app could be opened to automatically convert that bill's value into dollars.

Google also plans to fuse the camera with Goggles, so that augmented reality may be the future of visual search, Petrou said. "We'll use it where it's the right user interface," he said.

Goggles does have the capability to recognize faces, although that functionality hasn't been implemented in the app as yet. That might change as more and more people begin uploading data to the Web: if 17 different images of your face appeared on the Web, a picture take of you with Google Goggles would rank "you" in the top ten results about half the time. If there were 50 results, your face would be ranked in the top 5 results abour half the time, he said

Facial Recognition along with Geo-tagging is also available in Picasa web albums. You can already find who is connected to someone in facebook when you search for the people. Once all these information would start working together then you can identify the person where they have been on holidays (based on Geo-tagging of photos) and when they have gone there. Who else in their friends/family had gone with them, etc.

In fact FBI/CIA/MI5 may make their own app to "report potential terrorists" where if you see any suspicious person you can open one of their apps and click the photo of some person and the secret service will quickly check if this person is potentially a problem.

Of course we are not discussing the privacy concerns yet but looks like Scary future to me.

Tuesday 6 July 2010

Mobile Developer Economics 2010 and Beyond

A new report "Mobile Developer Economics 2010 and Beyond", offers many new insights into mobile developer mindshare, and analysis into every touch point of the developer journey, from platform selection to monetisation. The research is based on a set of benchmarks and a survey across 400+ developers globally, segmented into 8 major platforms: iOS (iPhone), Android, Symbian, BlackBerry, Java ME, Windows Phone, Flash Lite, and mobile web.

In terms of developer mindshare, our research shows that Symbian and Java ME, which dominated the developer mindshare pool until 2008, have been superceded by the Android and iPhone platforms. Despite Symbian remaining in the pole position in terms of smartphone market penetration, ‘out-shipping’ iPhone 4 to 1 and Android many-times to 1, the signs of dissatisfaction with the way the Symbian platform has evolved have long been evident.

Indeed Android stands out as the top platform according to developer experience, with close to 60 percent of developers having recently developed on Android, assuming an equal number of developers with experience on each of eight major platforms. iOS (iPhone) follows closely as the next most popular platform, outranking both Symbian and Java ME, which until 2008 were in pole position.

The report can be downloaded from here and is embedded below for convenience

Monday 17 May 2010

Mobile Phone Developments May 2010


HTC's 4G [sic] Phone is al ready to be rolled out. It is supposed to allow to transfer data averaging speeds of 3 to 6 megabits per second, and bursts hitting 10 Mbps. Ok, I can visualise some suspicious smiles but that's marketing. Its the data speeds of a normal HSPA network but it sells.

Inside the Evo is a 1 gigahertz Snapdragon processor, 512MB of ram, and 1 gig of built in memory. On top of those screaming specs are a 480×800 display, as well as two (count em!) cameras, the better of which packs 8 megapixels. Running it all is the newest version of Android (2.1), as well as HTC’s Sense UI for a little extra eye-candy. All told, this looks like an amazing phone to finally make use of Sprint’s fancy new network, and it may just be their best bet for reversing their falling fortunes.

The Evo 4G will allow for simultaneous voice and data and will be the first smartphone to ship with a YouTube HQ player and a video chat app from Qik to be used with the front-facing camera. Though Sprint's onstage Qik demo didn't work, we were impressed with the Evo 4G's speed (Sprint brought in a 4G tower for the event) as well the handset's 3D gaming capabilities and HDMI output.

As we learned at CTIA 2010, other goodies include an 8-megapixel camera on back, a 1GHz Snapdragon processor, Android 2.1, and an extra-large 4.3-inch capacitive touch screen.



Tired of losing your cell phone? Maybe you need a Zomm.

The new gadget is billed as a wireless leash for mobile phones reminding you when you've left your cell phone behind. Here's how it works:

You just pair the nugget sized Zomm with your phone over Bluetooth. Then you clip the Zomm onto you or attach it to your keychain. When your cell phones gets more than 30 feet away from Zomm, the Zomm unit starts to vibrate, flash lights and then eventually lets out a wail.

You can also use the Zomm as a Bluetooth speaker so you can answer calls through it, instead of talking straight into your phone.

The leash idea can work in reverse too. If you're the type who loses their keys more than their phone, you can just attach Zomm to your keys and then whenever you lose your keys, you can call Zomm and set off its alarm.

There's also a panic button. In case of emergency you can just press it and get help immediately, without dialing on your cell phone.

Bluetooth Special Interest Group (SIG) has named ZOMM as ‘One to Watch’, because of its innovative use of Bluetooth technology and universal appeal.

“Through the use of Bluetooth wireless technology, ZOMM provides an array of convenient applications for users,” said Michael Foley, Ph.D., executive director of the Bluetooth SIG.

“Its simple application of Bluetooth technology appeals to the masses – nobody wants to lose their mobile phone.”



Verizon Wireless and LG Electronics MobileComm U.S.A., Inc. announced the LG Ally™ will be available in Verizon Wireless Communications Stores beginning May 20. The first Android device from LG, the Ally is the perfect assembly of futuristic, stylish design and 3G Android power for customers looking to tackle life's most challenging feats and everyday ventures. Verizon Wireless customers can pre-order the phone at www.verizonwireless.com beginning May 13.


Until now, mobile users have been faced with a choice -- either type on a tiny keyboard or use a touchscreen keypad.

Neither is perfect but, so far, tiny but real keyboards have been winning out for many people. One of the many reasons cited by some BlackBerry users for not switching to an iPhone or similar device is that sensitive touchscreen keypad.

Some manufacturers have tried to give users the best of both worlds, a touchscreen and a pull-out keyboard, but search giant Google has another idea: make all mobile-phone keyboards obsolete.

With the recent release of its own phone, the Nexus One, users are beginning to experiment with what Google hopes is the future of mobile search: voice-and picture-based searching.

"Voice, we think, is just a natural way to solve a problem that exists on all phones, which is that typing is quite difficult, especially in certain languages like Japanese," said Alex Nicolaou from Google's office in Waterloo, Ont..

"Input methods are relatively onerous, whereas saying a brief phrase . . . is extremely fast . . . and there are just times when a picture really is worth 1,000 words.

"If you're standing outside a landmark and you want to know about it, it's obviously going to be much, much simpler to take a photo of that landmark and have the system tell you what it is, than it would be to figure out what name to type in, especially in a foreign country."

Google admits both are still in relatively early development stages and are not very reliable.

For voice searches, short strings of words work best. Even in noisy cafes, most four-or five-word searches worked well during testing. Nicolaou said one misheard word won't necessarily throw off your search results.

Google has hinted at some future features incorporating voice and image recognition. Engineers are working to improve the ability to photograph a printed page so it can be accurately scanned into text and quickly translated into another language. In a video posted online, a Google employee scans a menu from a German restaurant and uses his phone to translate it into English.

Google also hopes that, eventually, travellers will be able to speak a phrase into their phone, have it translated into another language and played back through their phone's speaker.


This season, big handset makers including Nokia, Microsoft and Motorola are betting you’ll want to flaunt cute, palm-shaped devices that look more like compact powder cases than brick-shaped mini-tablets.

Motorola is likely to introduce a new phone next month called Flipout that will have a 2.8-inch display, a 3.1-megapixel camera and a twist-out keyboard. We haven’t tested it yet, but on looks alone, it’s fabulous, darling.

Motorola’s square-shaped phone follows the release of Microsoft’s fresh-looking Kin One earlier this month. The Kin One has a 2.6-inch display, a slide-out keyboard, and looks like a rounded square when closed. In September, Nokia introduced the Twist on Verizon, a squarish phone with a 2.5-inch display. Even LG has a square-shaped phone called the Lotus, which has been available on Sprint for more than a year, and though it’s not exactly been a big seller, its looks are hot, hot, hot.

Microsoft released the final version of the desktop Office 2010, along with which it made available a flavor aimed at mobile phones, namely Office Mobile 2010. The owners of a device powered by Windows Mobile 6.5 can now take advantage of the Word, Excel, and PowerPoint editing capabilities of the application while on the go.

Among the features that Office Mobile 2010 comes around with, we can count SharePoint integration (users can easily access and edit documents stored on a Microsoft SharePoint 2010 site), Bluetooth controller mode for PowerPoint presentations, access to SharePoint Workspace Mobile, the possibility to easily take notes on the phone and to insert voice clips or pictures in them, and others more.

“Effective today, Office Mobile 2010 will be available for free via Windows Phone Marketplace for all Windows Mobile 6.5 phones with a previous version of Office Mobile. People using Office Mobile 2010 can perform lightweight editing of Office documents and take notes on the go.

As if mobile phone cameras weren't complex enough, Sharp has just announced a tiny 720p 3D camera for its mobile devices.

The 3D Camera Module has been made to fit inside either a compact point and shoot or a smartphone. The camera is crammed full of the latest technology, all of which enable it to capture both moving and still high resolution 3D images.

Things like colour synchronising processing, as well as 'fast readout' technology, help the tiny little camera to produce its images.

Sharp has made use of complicated high-density mounting technology in order to pack so many features in to this tiny device.

The company insists that the cameras will go into mass production by the end of the year.

Friday 23 April 2010

GPS to become commonplace and far more accurate


First it was Nokia that started giving away the Satnav software for free. Now Google is offering free Satnav software for Android phones in UK. Its already been available in US for quite some time and the response is generally positive.

According to comScore, the use cellphones for Satellite Navigation is becoming more common in Europe. According to them, in February, 21.1 million consumers in five large European markets -- Britain, France, Germany, Spain and Italy -- used their cellphones for navigation, 68 percent more than a year ago. This compares to 20.4 million personal navigation devices sold in those markets in 2008 and 2009 in total, according to research firm GfK.

I talked about Satellite based Internet before but today we will focus on satellite based GPS systems.

The GPS system, which was developed way back in 1989 for and by the military has been used by general public since the year 2000. Its has become very common in the last few years.

The GPS we know and love is part of a larger family of systems called Global Navigational Satellite Systems or GNSS. The following are the members of the GNSS; GPS is the USA system, GLONASS is the Russian system, Galileo is the European system and Compass is the Chinese system

The following is from the IET Magazine:

Satellite navigation systems take their location cues from 30 GPS satellites that circle the Earth twice a day transmitting status, date and time, and orbital information. Soon there will be around 100 satellites to lock on to as GPS is joined by global constellations from Europe (Galileo), Russia (GLONASS), and China (Compass).

GPS wasn't built to help us find our way to the shops - it was a Cold War project funded by the US Department of Defense to ensure that nuclear submarines could surface and target their missiles accurately. There are strategic rumblings about the new satellite constellations too, but the current consensus is that civilians have most to gain from more accurate and reliable location and tracking applications. That's if receiver designers can get the power consumption under control.

Russia's GLONASS system used to be famous for its satellites failing faster than they were launched, but since last month it has had 24 functioning satellites in orbit. Meanwhile, Europe's much-delayed Galileo system will have 14 satellites operating by 2014, according to the European Commission, with the full 30 available by 2017. The US GPS system is being modernised to become GPS III by 2013, with additional navigation signals for both civilian and military use. Information about China's Compass system is sketchier - it was going to be a regional system but is now understood to be global.

'All this activity is great news because whatever the application, there will potentially be multiple constellations to get a position fix from, which will help with signal integrity in safety-critical environments such as maritime, aviation or rail, and accuracy for mobile phone users in urban areas,' says Andrew Sage, director of Helios, a consultancy specialising in satellite navigation.

A GPS receiver should be able to 'see' at least four GPS satellites anytime, anywhere on the globe and establish three position coordinates (latitude, longitude, and altitude). But in city streets hemmed in by tall buildings, a receiver is unlikely to be able detect more than two satellites and the signals will often have bounced off structures.

'For the average pedestrian, the position fix can be a long way out and very unpredictable,' says Sage. 'Most users don't see that today because GPS receivers match us to maps and smooth the errors out. But if you are walking around a city and not on a road in a car, multi-path reflections are a problem.'

The more satellites visible from within these 'urban canyons', the easier it is to carry out consistency checks on the received signals. 'Even when you can't isolate the multipath-contaminated signals, the more signals you have, the more your errors average out,' says Dr Paul Groves, lecturer in global navigation satellite systems (GNSS), navigation and location technology at UCL.

Better GNSS integrity would enable new applications, such as road-user charging, enforcing bail conditions and pay-as-you-drive insurance. 'Clearly, if position information might be used as legal evidence, it has to be reliable,' says Groves.

The delayed arrival of Galileo and the resurrection of GLONASS have complicated matters for receiver makers. Galileo was designed to offer the simplest possible upgrade path from GPS to a dual-constellation system. Agreements were made to put the carrier frequencies of the main open services in the same part of the spectrum as GPS, at around 1575MHz, so receivers could share the same radio, analogue components and antenna. Both systems also send their signals using a spread-spectrum code-division multiple-access (CDMA) approach. GLONASS uses a frequency-division multiple-access coding technique (FDMA) and a main open-service carrier frequency of 1602.2MHz.

The complete IET Magazine article can be read here.

There is another interesting article titled 'GPS, GLONASS, Galileo, Compass: What GNSS Race? What Competition' here. Interesting analysis.