Making Sense of LTE

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LTE- Radio Validation Challenges!

Last week I was in Gurgaon, for a partner conference. During the break, some of the attendees wanted me to talk about present day challenges in rolling out LTE and solving those challenges. 

The day prior, while I was working on my notes, I did not have clue about audience requirement. Interestingly, I got lucky, as I got some notes prepared in that regard, where I summarized my findings in presentation format.

If you would be interested to know more about ‘LTE Radio Validation Challenges’, please feel free to download the copy of my presentation here.   

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CellAdvisor RAN-Performance Indicator: All you need to know about Product feature

Last year, JDSU has launched 'RAN Performance Indicator' feature, for its Base Station Analyzer (BSA) (745X/785x) series product line. Marketed as RAN-PI, the feature gives insight into serving eNodeB's LTE UL and DL parameters, simultaneously, by pulling UL data from ‘True Site’ Handy, along with displaying DL data from BSA, on BSA screen.

As per JDSU, RAN-PI provides integrated communication assessment, by providing integrated measurements of the cell-performance (and user experience) (communication performance indicator). In short, the feature provides integrated view of user experience (DL) and cell-site performance (UL), of LTE base station, on BSA screen.

How does it work? According to JDSU, RAN-PI integrates parameters from ‘True Site’ and BSA, both, by scoring and then correlating measurements, according to some logic, which is customizable, as per customer requirement. The best part is, you can actually see, various parameters, including LTE UL/DL EAFRCN, CQI, EVM, DL Throughput and others on BSA screen simultaneously, which gives users enough insight to identifying problems and helps in resolving them quickly.

Why RAN-PI is important? First, it integrates JDSU's ‘True Site’ handy walk-test tool information, with BSA's own set of parameters. Second, users can choose which parameters need to display and rate them as per the acceptance test criteria, before displaying it on BSA screen. Lastly all parameters (pooled from ‘True Site’ and BSA), are displayed on single screen, which users can save directly to prepare final AT report.

While I was trying to understand, where this feature is going to be important, JDSU product team is quite quick to share a used case- eNodeB Acceptance Testing (AT) procedures. Traditionally, doing AT of a Cell Site requires carrying out SCFT or Post walk test, if it is Indoor DAS. Imagine now, you are asked to carry AT procedure for an Indoor DAS Cell Site. First thing you will do is to carry out Walk test with ‘True Site’ handy tool. While ‘True Site’ is powerful enough, it does not give complete picture after all. What if you are also carrying BSA with you and at a particular location, you measure both parameters, reported by BSA (which includes EVM, Frequency error) and ‘True Site’ (RSRP, RSRQ), and save integrated display of parameters, to analyze the problem and reach to conclusion immediately; that is quite possible. All you need to do is to carry BSA with you and connect ‘True Site’ to it on Bluetooth. BSA will then automatically fetch configured parameters on screen.

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Samsung Galaxy S4-GT I9507- how does it support LTE?

So I have been using ‘Optus Samsung Galaxy S4 GT I9507’ Smartphone for LTE UE Validation testing. Questions is-how do we choose the Smartphone for LTE Pre-Post Network Launch Validation?

Let's start with the kind of LTE Band support required. Assumingly we need to test LTE for Band 2300 or Band 40, we need to check whether the Optus S4 supports this LTE band or not.

The best way to do this is to visit Manufacturer’s webpage. Although, I thought the phone is TDD LTE, the story is quite different.

How do we check, if a particular Smartphone supports particular LTE Bands? There's no easy way to do this, but there's a Google Play Store App- 'CPU Z', which tells you more detail about underlying SoC (Read: System on Chip) hardware. Based on the information you need to investigate further.

Other way is to visit the manufacturer’s webpage which enlists devices specs, as we did earlier, and check, if there's any country specific LTE Band support for device model is available. If you don't find such information (specific to your country’s LTE band support or model launched), I guess then you need to wait till that particular model is launched with country specific LTE support.

Samsung S4 smartphone, which I'm using, is 'Optus LTE' device. So naturally, the starting point is to see, if Optus has launched LTE and if yes, which are the smartphones available in Australian market, which supports Optus LTE bands. After researching some information, I could find out that Optus has launched LTE on both FDD and TDD modes and Samsung Galaxy S4 is one of the devices available, which supports both LTE modes.

Quite long story indeed!  

So now, I could find out that the Smartphone Galaxy S4, which I’m using for UE validation testing, supports both LTE TDD and FDD modes ('Band 3' and '40') of operations.

Now let's dig down little dipper.

My 'CPU Z' mobile App, which we talked earlier, shows that Galaxy S4 GT I9507 has Qualcomm's Snapdragon 600 series SoC inside. Interestingly this brought one more question to my mind- how does S4 supports LTE/HSPA/3G/GSM Cellular connectivity, as SD 600 series SoC doesn't have Cellular Chipset for connectivity (as part of SoC).

Why this is relevant to find out?

Just because, as per Optus data on phone, S4 does support LTE Band 3 and Band 40 both, but as per our investigation of SoC, there's no cellular connectivity chipset available, as a part of 600 SoC Architecture.

Now, we need to dig down dipper for this. I decided to take help of AnandTech, the best source on Smartphone SoC and hardware testing.

As per AnandTech, Samsung Galaxy S4 is a Cat 3 LTE device, which supports upto 100 Mbps data speeds on downlink (e-NodeB to UE) and 50 Mbps on Uplink (UE to e-NodeB). The device's LTE band support varies from market to market. But we already know that the device, which we have, is Optus S4 and supports LTE Band 3 and Band 40, both.

But we haven't got the answer yet. How does S4 GT I9507 support cellular connectivity?

I looked at data available from 'CPU Z' Android App. In the system tab of app's interface, I observed that S4 has 'System board' of Qualcomm's MSM8960 chipset. Qualcomm has launched MSM (Mobile Station Modem) 8960 Chipset in year 2010, which not only support CDMA-EVDO bands, but also multi-carrier HSPA+ and LTE networks. A little dig down dipper shows how Qualcomm support LTE inside S4 GT I9507.

Why do we need separate chipset (MSM8960) for Cellular Connectivity? If you see this page, you would find that Snapdragon 600 SoC, which Optus Galaxy S4 is using, doesn't have modem support available. So to provide cellular connectivity (via modem), 600 SoC is using MSM8960 chipset, which provides complete integrated cellular connectivity solution.  

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The idea behind this LTE Blog!

Welcome aboard! 

I'm no expert on 'Long Term Evolution' technology aka 'LTE' or popularly known as '4th' Generation of technology, but I want to share my thoughts about it over coming months. It's all not that easy.

Reason, I want to write about LTE is far more simple to understand. But let me put forward some ideas, which I wish to bring to life, by writing.

4G is quite complex technology to comprehend is one go. It's quite different from its predecessors. Should we make it simpler to people to understand and make use of it?

There's no dearth of resources on 4G, but then it all depends on who you are and what are you looking for. Can we talk about technology beyond jargon?

LTE, as said, would be stepping stone to our long ambitious goal of creating a 'Connected Society', where we perceive that LTE/4G or its successors (5G), would make the dream of connecting every individual on the planet true. What should be the ultimate goal of a telecom technology generation?

In the end, as technology evolves and become more advance and superior, how it is helping people around us to make their lives easier and better?

I would explore some of these ideas, but there's no such limit.

BTW, who am I talking about these all things?

I'm the creator of 'Telecomblogs' and 'Telecomblogs News Network'- the blogs which talks more about business or non-technical aspects of telecom world. I'm really proud to have those two babies.

But then over the years and course of my adventures with the technology, I started feeling that we need to talk about this. And we can't mix it up with existing platforms. Yes- you got it write- it's long road ahead.

So stay tuned here.

The blog would revolve around LTE as technology, but that's just anchor. We are about to start.