Lecture 01

[Music] hello and welcome to this course on 5G uh wireless standard design and this is the first class on uh this course so we'll be briefly introducing you to this course what will be covered and what will you learn at the end of this course so let's get going so if you uh look at the 5G Network architecture which most of us are like familiar with in the sense that we see uh our mobile equipment we see uh what is uh there on the towers so if you look at it we there are these users which are basically mobiles and they communicate with the base station so base station is a device which you see which is located on the tower and so what happens is if you want to transmit some uh data to to other user so it the data goes from the user to the base station and then it captures the signal and then it processes and it sends it back to the other user okay so uh this course will teach you what processing the user does when it actually it has some data to transmit what processing uh base station does when it has data to receive and what processing happens here so we'll we'll teach you all that so if you look at it uh the base the architecture of a 5G Network it consists of a base station base station is basically like this is the device which captures the signal or which if the data has to be transmitted in this direction it transmits the signal so uh this is called the this base station consists of two uh nodes one is called the remote radio head and another one is called the baseband unit so the remote radio head captures or transmits the signal and the actual processing is done in this the basan unit which is the heart of the base uh base station and there is this core Network which for example does the billing authentication so uh now uh in any network there are two directions which are defined first one is called the down link so if the data has to be transmitted in this direction from the uh from the base station to the user it is called the downlink direction which essentially means that the user has some data to receive and if the uh user wants to transmit some data if user has some data to transmit it is called the Uplink Direction okay so now in this course what I'll be teaching to you is basically the 5G physical layer standard and what what does that mean it means that whatever is required for the base station to process the data okay to actually transmit it on air that's that's what is called the physical layers so as a communication engineer if you uh like if we I briefly tell you it's what it is it is basically how does the data get modulated how does it get encoded and how does it get transmitted on air so that's what I'll be teaching you and I'll teach you in both the direction in the Uplink and in the down link Direction so at the end of this course you will know what is what processing your mobile does what processing the base station does to enable this communication between different users between different devices so but before we get into the integrities of this 5G wireless standard let's go back and understand the a brief history of these Wireless standards okay so uh we are talking about 5G but of course there are 1G 2G before that so uh 1G it was like based on analog transmission and analog basically AM FM which most of us are familiar with okay so what were the different standards multiple different standards first one was this Advanced Mobile phone system amps and it was developed within North America it was used there okay then there was this Nordic mobile telepone which was which is called nmt it was jointly developed by Network operators of Nordic countries then there was this tax Total Access communication system it was used and developed only in UK mostly in UK and you see that now there are like three different stand standards uh for this 1G and used across different countries and another particular feature of this 1G mobile communication system was that it was limited to voice services but crucial feature of this standard was that it made mobile telephony accessible to Ordinary People before that it was a niche service and it was limited primarily to Army and some few Niche Services okay so now this was 1G but the crucial part was that it was there were three different standards used across different countries and it was analog and it was limited to Wi Services okay so analog communication has its own limitation and from 1G to 2G we moved from analog to digital okay so digital made this digital transmission made a lot of uh uh processing uh uh became easier because of this digital uh transmission and uh we'll understand how this digital communication helps but the target service was still wise and but this use of digital transmission allowed limited data services and all of us are comfortable with using this something called sms okay short messaging services which is like used day in and day out but the target service was still wise and again there were multiple standards there was this GSM communication global system for mobile communication it was jointly developed by European countries so you see that like this standard basically was developed by multiple countries and used across multiple countries but primarily limited to the European countries in the beginning then there was this digital version of apps which was again developed within North America then personal digital cellular PDC it was developed and solely used in Japan again three different standards and used across uh different countries so if you have to move from one country to another you have to basically use a different mobile phone this feature was like was similar to 1G where in this these standards were not interoperable and you had to use different devices if you are moving from one country to to other then there was this another standard code uh CDMA based is-95 technology again a different kind of Technology but primarily meant for vice and used for some limited use of data so four different standards and then but what happened was GSM became popular and it spread from Europe to other part of the world and uh then we don't hear about all these Technologies okay so it became popular because of certain features it had and most of the countries across the world started using this this particular technology for 2G so but conclusion of this is that there are four standards one of them became popular but still being used for vice and a very limited data service then we moved from 3G 2G to 3G and people became comfortable with voice they started demanding uh and they more of data because initially uh like 2G was providing only very limited data service in terms of SMS and that's where 3G came in and the IT enabled high quality mobile uh broadband and which enabled fast Wireless internal access again two different standards which were like one was HSPA this was called highspeed packet access and another one was CDMA 2000 CDMA 2000 uh like it was an evolved version of CDMA 2G but both of them allowed high quality uh mobile broadband they were primarily designed for voice and data together so in the beginning itself it was like decided that the 3G should be different in the context that it should be designed for both voice and data so so it was it started providing data services but the data rates were not very higher and then uh came this 4G which is basically it is called LTE standard and now before 5G all of us were using that and continue to use that and the big difference between 3G and 4G was that it was it enabled a transmission over wider bandwidth so if you look at 4G it enables communication over 20 MHz of bandwidth which is actually 10 times of what 3G was offering and then wider bandwidth means higher data rates but they come with their own challenges a wider bandwidth has its own challenge of for example it has the channel estimation which we'll see later in detail the channel estimation becomes tough but then technology had basically matured so much that it enabled implementation of ofdm based devices and as we'll see later that ofdm enables implementation of a wideband uh system very easily and the reason being that is the channel estimation and Equalization becomes very easy so the basic difference in philosophy of 3G and 4G was it was designed to provide High data rate connectivity so the stress was on building a wireless standard which could provide High data rate connectivity so you see that the uh philosophy is slowly changing where in 1G and 2G the focus was on uh providing voice Services 2G had uh was providing little little bit of data services in terms of SMS and then we moved from 2G to 3G where in the stress again was on giving the was on giving the data rate connectivity and then but here the 4G like the focus was on giving essentially was on giving High data rate connectivity but uh 1G to 4G standards they were designed for humans to communicate so the basic difference when we moved from 4G to 5G since it was felt that humans are communicating and they are able to get a good data rate connectivity so what is what should how should 5G be designed and uh 5G is is basically uh designed for machines to communicate and you will see that if like it is designed for three different use cases and each one of this use case has its own challenge so use case one basically is called enhanced mobile br and it is this use case is basically similar to the earlier use cases wherein the the philosophy is to provide High data rate and high traffic volumes and this is like all of us are familiar with that wherein we want to like upload or download high qu high bandwidth data high with high data rate connectivity so this is this use case is a bread and butter of any wiress standard but along with this the 5G is being designed for enabling two different different use cases so this is use case 2 wherein we it the 5G enables which is unlike any of these other standards it enables machines to communicate and uh this you look at this there is this as machine type communication which is the use case to so what does it do this use case it allows to connect Massive number of low cost low energy consumption devices and just to give you an example so you have an electricity meter which is which needs to like transmit its reading to some server so what it does is it wakes up in the morning and then it transmits few bits of data which is basically its meter reading and then data gets uploaded on server now this use case doesn't require High uh data rate but what it requires is that like whenever it has data to transmit it should be able to transmit plus the we should not be charging these electricity meters unlike these mobile phones which we uh charge daily so this is a basic difference that it should while transmitting data these kind of meters should consume uh very little energy so that they go on forever see the philosophy difference that here like we don't mind charging the phone every day but we mind charging this kind of meters electricity meters every day and so the standard should be designed to basically incorporate this kind of requirement wherein uh like it should be uh it should allow electricity meters to transmit their data but at by consuming very low amount of energy and uh so 5G is designed to cater that also so this is use case 2 use case three then 5G is designed to support something called URC which is ultra reliable low latency communication and just to give you an example when there is a driverless car and it has like it has to decide based on some AI engine running okay now uh if the this communication has to be ultra reliable because if there is an error in this communication and instead of turning left the car turns right there will will be an accident okay so there cannot be any compromise with the reliability part and this has to have uh low latency also because if there is a high latency then a car might not be able to decide at the right time again there are chances of meeting with an accident so 5G is designed to support that as well okay so this is another use case so you look at this this use case more or less was supported in 4G also but 5G is will uh support these use cases also and it's like we'll see how 5G is basically crafted to support three different use cases is with widely different uh kind of requirement right we we don't mind if basically there is some some error in the data here in anas mobile broadband so if there is you the video gets corrupted you can re rewatch it but here that doesn't happen Okay so 5G has to support that and here you look at this we don't mind charging these devices every now and then but here we mind okay there's a lot of comfort in uh charging these devices uh every uh day or every week also so you want to install these devices and get done with them okay so these 4G and 5G standards they were and they were designed by this uh standardization body which is called 3G partnership project there's a brief history associated with it why is it called 3G PP because different companies came together to design the 3G standard and and the same standardization body continues to design the 4G and 5G standards as well and but the name has not changed okay name has stuck on and it is called 3gpp so you see that this uh body designs uh 4G 5G and continues to design evolution of 5G standards also now this all these 3gpp documents they are basically divided into releases and each release release has a set of features new features compared to the previous release so why are we talking about it because uh if you look at it release is a document and we will refer to these documents in our study in this course and uh 4G is basically defined from release 8 and onwards okay so release 8 was the Baseline version of 4G then release 9 release 10 and so on okay so each of this release had new set of features built upon the existing release so from release 8 to release 14 it is 4G release 15 is known as 5G okay and it is called it's given a name 5G new radio because we were doing something new which was different from 4G and to differentiate it we basically started calling it new radio so if you read books if you read standard it is called 5G NR okay so and designed by this standardization body 3gpp so what we will do here is we will refer to these documents and these documents are called technical specifications they are organized in multiple series but as I told in the beginning of this class that we will be focusing primarily on physical layer okay and physical layer essentially include the processing which is is required for transmitting and receiving data on air so our interest is in basically uh this 38 series document and what it covers is a transmitter plus receiver design aspects for this 5G newr new radio and this transmitter and receiver they together they are called transer design so we'll be focusing on these series document now so to summarize okay so what this 5G course will teach is basically the processing required for transmitting the data uh from the base station to the user and uh from the user to the base station okay now this 5G uh standard is being designed is being designed for a particular Spectrum to operate at a spectrum is basically a a chunk of bandwidth which is located to an operator where a part particular system can operate okay so you look at it so what is this frequency band it is operating uh frequency range just for an example if BSNL there are we have different operators BSNL AEL Gio so each one of them is given a different band where their system can operate so that they don't interfere with each other now the frequency banned for 1G and 2G they were like around 800 900 MHz and but there were some other few lower and higher band but but typically centered from 800 to 900 MHz with 3G and 4G new bands were added at both lower and higher frequencies and uh the Spectrum uh spans from 400 MHz to 6 gahz okay you see this we from 2G to 3G and 4G we moved from 800 to 900 and then to 450 to 6 GHz range okay now what happens is the bands at lower frequency they have a good propagation property so just to uh give you an example if you're operating at uh 800 to 900 MHz your signal can transmit at a larger distance or can travel at a larger distance uh but if you move up the Spectrum okay then the distance uh traveled by the transmit signal is far lesser than when it is uh basically being transmitted at a lower frequency so now band at lower frequency they're good for wide area coverage deployment and typically they are used we have these mobile phones being served everywhere okay now this band because of its properties in 800 to 900 and typically below 3 ghs are very popular because of the excellent prop propagation properties they have but as we move up the frequency there like the propagation proper properties because of that it becomes difficult to use for wide area coverage and the reason as I just told you was that a simple reason that the signal is not able to uh propagate to a longer distance there is a lot of attenuation a simple reason okay and now if that is not possible then we cannot use this higher band for typical urban and rural deployment but uh spectrum is limited in these band so if you have to move to high band you how do you what kind of system do you design 5G is being designed for higher Spectrum Spectrum uh also and how will we how is 5G using them this basically used for boosting capacity in uh dense indoor indoor deployment where user is not very far from the base station so if you look at this uh an example where like you have a like we all of us are comfortable with Wi-Fi kind of deployment where we are not very far so even for 5G 5G is basically looking at these kind of uh dense indoor deployment and using this higher Spectrum band there now 5G as I said basically it wants to transmit data at a higher rate and higher capacity in this dense deployment so uh this 5G is being designed for two different uh frequency ranges okay so uh this first frequency range it is basically includes all the existing and new bands before uh below 6 GHz so this is called frequency range one other than other frequency range which is called f fr2 it basically is a it is the higher frequency band it it includes all the new bands in this range okay so fr1 is 6 GHz f fr2 is uh includes the higher frequency band from 24 to 52.6 GHz and operating bands have a number where where this 5G bands are numbered from N1 N2 N3 Etc and uh 3gpp release 15 okay they said that's a initial release and it specify 26 different operating bands in Fr fr1 and three in F fr2 okay so these you see this these operating bands uh can be allocated to different operator so that their transmission don't interfere with each other we'll see as we uh go along that the maximum bandwidth which is supported in this F fr1 is 100 mahz and as we move up to uh go to F fr2 maximum or bandwidth which is supported here is 400 MHz so each operator can be assigned 400 MHz of bandwidth here 100 MHz of bandwidth here okay so just to keep in mind that uh because of the extreme data rate requirement which 5G is defi designed to offer for these it is being designed for uh different kind of bands and this band where in fr1 which is below 6 GHz the design is completely different from fr2 where it is designed uh for very high frequency range so this is called sub6 GHz and this is called millimeter Wave band okay and as uh I'll teach you that the design becomes certainly different and and uh 5G has to basically take care of all these requirements and just a little bit about the books which we will be referring to the reference material so uh we'll be following these two books closely and and these uh these are excellent books to refer to uh for this uh this course and uh the reference for today's lecture is basically these three chapters I picked up a few ideas from these three adaps and the rest of the logistics will be uh basically will be let known to you the idea here is to summarize that uh like I'll be what will be covered in this course is the phys 5G physical Air Design and we'll be teaching you what is required for the base station to transmit the data on air or receive the data and similarly for the uh for the Mobile station which has to transmit and receive the data thank you [Music] [Music] [Music]