In the course of evolution of RAN ( Radio Access layer) technologies 5G outsmarts 4G-2010 which comes in succession after 3G-2000, 2.5G, 2G -1990 and 1G/PSTN -1980 respectively. Among the most striking features of 5G –
entirely IP based
ability to connect 100x more devices ( IOT favourable )
speed upto 10 Gbit/s
high peak bit rate
high data volume per unit area
virtually 0 latency hence high response time
Thus it can accomodate the rapid growth of rich mulimedia application like OTT streaming of HD content, gaming , Augmented reality so on while enabling devices connected to Internet of Things sto onboard the telecommunication backbone with high system spectral efficiency and ubiquitious connectivity .
Infact 5G has seen maximum investment in year 2020 in revamping infrastrcuture as compared to other technologies such as IoT or even Cloud. This could be partly due to high rise in high speed communication for streaming and remote communication owining to steep rise in remote learning adn working from home scenarious.
mid- band spectrum (2.5–10 GHz) – a combination of good coverage and very high bitrates,
high band-spectrum (10–100 GHz) – the bandwidths needed for the highest bitrates (up to 20 Gb/s) and lowest latencies
Workplan for 5G standardisation and release
The Workplan started in 2014 and is ongoing as of now (2018)
image source : 3GPP “Getting ready for 5G”
3GPP is the standard defining body for telecom and has specified almost all RAN technologies like GSM , GPRS , W-CDMA , UMTS , EDGE , HSPAand LTE before .
Applications of 5G
5G targets three main use case
enhanced mobile broadband (eMBB),
massive machine type communications (mMTC)
ultra-reliable low latency communications (URLLC) (also called critical machine type communications (cMTC))
LTE stands for Long Term Evolution and is a registered trademark owned by ETSI (European Telecommunications Standards Institute) for the wireless data communications technology and a development of the GSM/UMTS standards.
Both radio and core network evolution
All-IP packet-switched architecture
standardised by 3GPP
lower CAPEX ans OPEX involved
LTE evolved from an earlier 3GPP system known as the Universal Mobile Telecommunication System (UMTS), which in turn evolved from the Global System for Mobile Communications (GSM). Also it is aligned with 4G (fourth-generation mobile)
It is backward compatible with GSM/EDGE/UMTS/CDMA/WCDMA systems on existing 2G and 3G spectrum, even hand-over and roaming to existing mobile networks.
Motivation for evolution – Wireless/cellular technology standards are constantly evolving for better efficiency and performance.LTE evolved as a result of rapid increase of mobile data usage. Applications such as voice over IP (VOIP), streaming multimedia, videoconferencing , cellular modemetc.
It provides packet-switched traffic with seamless mobility and higher qos than predecessors. Also high data rate, throughput, low latency and packet optimized radioaccess technology on flexible bandwidth deployments.
Timeline of Evolution
GSM : calls on circuit switching ( CS ) between 2 parties for communication. Dedicated circuits are used for voice and SMS.
GPRS : packet switching (PS) is introduced for data services
UMTS / 3G : network elements begin evolving into PS . No changes to core.
EPC / LTE/VOLTE : No circuit switched domain at all .
Range from 1.4 MHz up to 20 MHz. Ultimately bandwidth used by carrier depends on frequency band and the amount of spectrum available with a network operator
downlink: OFDM (Orthogonal Frequency Division Multiple Access) 100Mbps+ (20MHz spectrum)
Multi-Antenna Technology , Multi-user collaborative MIMO for Uplink and TxAA, spatial multiplexing, CDD ,max 4×4 array for downlink
Coverage
5 – 100km with slight degradation after 30km
LTE architecture supports hard QoS and guaranteed bit rate (GBR) for radio bearers.
Technology
All interfaces between network nodes are IP based Duplexing – Time Division Duplex (TDD) , Frequency Division Duplex (FDD) and half duplex FD
MIMO ( Multiple Input Multiple Output ) transmissions –
Allows the base station to transmit several data streams over the same carrier simultaneously. Modulation Schemes
QPSK, 16QAM, 64QAM(optional)
LTE Architecture
Primarily composed of
User Equipment (UE)
Mobile Termination (MT)
Terminal Equipment (TE)
Universal Integrated Circuit Card (UICC) : also known as the SIM card for LTE equipments. It runs an application known as the Universal Subscriber Identity Module (USIM).
2. Evolved UMTS Terrestrial Radio Access Network (E-UTRAN)
handles the radio communications between the mobile and the evolved packet core. High level representation for eNodeB or eNB
Role of eNB : sends and receives radio transmissions to all the mobiles using the analogue and digital signal processing functions of the LTE air interface. eNB also controls the low-level operation of all its mobiles, by sending them signalling messages such as handover commands.
3. Evolved Packet Core (EPC)
This sub system resembles IMS environment.
Packet Data Network (PDN) Gateway (P-GW) communicates with the outside world simillar to GGSN ( GPRS support node ) and SGSN ( serving GPRS support node ) in UMTS and GSM.
Home Subscriber Server (HSS) is a central database that contains information about all the network operator’s subscribers. Almost simillar to HLR/AAA in 2G /3G architcture.
Mobility management entity (MME) controls the high-level operation
For a roming user in Visited-PLMN , he is connected with the E-UTRAN, MME and S-GW of the visited LTE network. However, LTE/SAE allows the P-GW of either the visited or the home network to be used, as shown in below:
For roaming prepaid charging , accounting flows are made to access prepaid customer data, via P-Gateways or CSCF in an IMS environment.
LTE-Advanced
LTE devices capable of CAT6 speeds (Category 6 ) Increased peak data rate – downlink 3 Gbps, Uplink 1.5 Gbps ( 1 Gbps = 1000 Mbps) Spectral efficiency from 16bps/Hz in R8 to 30 bps/Hz in R10 Carrier Aggregation (CA) Enhanced use of multi-antenna techniques Support for Relay Nodes (RN)
Where 2G is referred to as the GSM era , 2.5 G as the GPRS with GSM era. As compared to its predecessor 1G which used FDMA ( Frequency Division Multiplexing ) for channelization , 2G used used TDMA and CDMA for dividing the channels .
SISO – Single Input Single Output SIMO – Single Input Multiple output MISO – Multiple Input Single Output MIMO – Multiple Input multiple Output
Multiplying the capacity of a radio link using multiple transmission and receiving antennas to exploit multipath propagation. Key technology for achieving a vast increase of wireless communication capacity over a finite electromagnetic spectrum.
Antenna configuration – implies antenna spatial diversity by useing arrays of multiple antennas on one or both ends of a wireless communication link boost channel capacity. combats multipath fading enhance signal to noise ratio, create multiple communication paths
Applies to wifi IEEE 802.11n (Wi-Fi), IEEE 802.11ac (Wi-Fi) as well as cellular networks HSPA+ (3G) WiMAX (4G) Long Term Evolution (4G LTE) power-line communication for 3-wire installations as part of ITU G.hn standard and HomePlug AV2 specification
Large capacity increases over given bandwidth and S/N resources Greater throughputs on bands below 6 GHz,
multi-user MU-MIMO
simultaneous independent data links to multiple users over a common time-frequency resource
massive MIMO
enable the expansion of the useful spectrum to microwave and millimeter wave bands within the framework of 5G cellular communication.
microdiversity MIMO
MIMO modes (60m)
Diversity – Alamouti algorithm Beam forming – create and aim the antenna pattern electronically Spatial multiplex – use of precoding and shaping to unravel the multipath signals
challenges faced by mobile equipment vendors implementing MIMO in small portable devices.
Functions
3main categories: precoding, spatial multiplexing (SM), and diversity coding.
Precoding
multi-stream beamforming ( signal is emitted from each of the transmit antennas with appropriate phase and gain weighting such that the signal power is maximized at the receiver input ) , increases reception and reduce multipath fading
In line-of-sight propagation, beamforming results in a well-defined directional pattern. However, conventional beams are not a good analogy in cellular networks, which are mainly characterized by multipath propagation. When the receiver has multiple antennas, the transmit beamforming cannot simultaneously maximize the signal level at all of the receive antennas, and precoding with multiple streams is often beneficial. Note that precoding requires knowledge of channel state information (CSI) at the transmitter and the receiver.
Spatial multiplexing
High-rate signal is split into multiple lower-rate streams and each stream is transmitted from a different transmit antenna in the same frequency channel. If these signals arrive at the receiver antenna array with sufficiently different spatial signatures and the receiver has accurate CSI, it can separate these streams into (almost) parallel channels.
increasing channel capacity at higher signal-to-noise ratios (SNR).
Diversity coding
when there is no channel knowledge at the transmitter , a single stream is transmitted. The signal is emitted from each of the transmit antennas with full or near orthogonal coding. Diversity coding exploits the independent fading in the multiple antenna links to enhance signal diversity.
From ARPANET(Advanced Reseracha nd Prjects Agency Network) in 1973 by US dept of defence , invention of HTTP in 19196 and finally evoluation of SIP in 2000 and availiability of broadband ethernet services, the telecom landscape has evolved.
As far as infrastructure, services, and contents are concerned, the VoIP industry is witnessing a migration from POTS / PSTN/ Legacy integrations to NGN (Next Generation Network).
NGN is being implemented globally as a means to change the cost base, agility and service capabilities of telecoms providers. The evolved architecture for the transition is one that provides flexibility to service providers by enabling them to deploy new services on IP based technologies, while leveraging existing services and infrastructure as long as it makes sense.
This post describes the evolution of voice communication in access , transport and session layers respectively.
1G
2G
3G
4G
5G
Year of dev
1970-1984
1980-1999
1990-2002
2002-2010
2010-2015
Launch year
1987 by Telstra Australia
1991 in Finland by Elisa
1998 pre-commercial launched by NTT DoCoMo in Japan , branded as FOMA.
2009 in Stockholm (Ericsson and Nokia Siemens Networks systems)
We see that the speed enhances considerably with every generation- 1G offerd 2.4 kbps, 2G offered 64 Kbps based on GSM, 3G offered 144 kbps – 2 mbps whereas 4G offers 100 Mbps – 1 Gbps with LTE technology .
It is to be noted that one of requirements set by IMT-2000 was that speed should be at least 200Kbps to call it as 3G service and 384kbps ( wth stationary speeds of 2Mbps) for a “true” 3G.
IP transformation in access layer
Note that voice calls in GSM , UMTS and CDMA2000 were circuit switched but with newer technology voice calls became packet switched too and a lot of rereginerring was required.
LTE (Long Term Evolution) is a series of upgrades to existing UMTS technology involving OFDM and MIMO and newer upgrade were called LTE advanced also. Upcoming 5G offers speeds upto 35.46 Gbps.
Transport Layer
IP transformation in transport layer
Session Layer
While 2G introduced services like SMS , MMS , internal roaming , conference calls, call hold and billing based on services e.g. charges based on long distance calls and real time billing which were unheard of in 1G , there were challenges in terms of page load speed for interactive websites .
As 3G came into picture, usecases also enhanced with multimedia features siuch as fast web browsing, maps navigation, email, video downloading, picture sharing and other Smartphone technology
IMS at work from visiting to home locationAccess network agnostic
It is noteworthy that SKYPE provided VoIP services ( since 2003) much before mobile phone had 2G/3G ( 2010). In current times with many fantastic options to choose from( whatapp , FB messenger , insta cht , Viber , Hangouts ..) given the high bandwidth with 4G/5G and mych advanced media / signal processing tech , the glocal voip scene is touching 400 mililion subscribers and looks very attractive with 1.5$ billion market .
Enterprise communication systems
On premise private branch exchanges ( PBX ) were the first kind of business telephone systems to which the analog PSTN systems of the company were conneced. These analog circuits were then replaced by digital PBX which provided enhanced features liek screening , voicemails , shared lines.
In the current landscape , the digital PBX of the company is connected to the external telco privider via a SBC or SIP trunking service .
An ompremise LAN based voIP system can be accessed from outside via a VPN on SSL/ IPsec. Although it incures greater CAPEX but ensufe maximum control and ownership of the data . Many time the local laws mandate the server to be hosted with a partuclat geographical area too where an on premise setup and data centre is used.
Enterprise communication shifts from on-premise to SaaS (cloud)
As for remote worksforce and employees working from home (such as during lockdown , pandemics ) it is even more crticial for enterprises to maange inter communication between teams and keep the communication private ie not using piblic messaging platforms , hence the role of cloud based PBX integrated with secure and end to end encrypted telco providers is of prime importance .
To read how a SME can setup their own flexible and scable enterprise comunication system read –
With the advent of other disruptive technologies such as free and opensource codecs in browser with WebRTC and well defined framework and standards , voIP definetly looks detsined to expand by leaps and bounds.
Second generation or 2G of telecom emerged a decade after (1990) its predecessor 1G (1980). Although the history of telecom evolution truely beings with internet and further engineered with PSTN, analog voice and switches we shall omit them discussing here as they are truly legacy now. You can read more about Legacy telecom here-
I use the term legacy telecom system many a times , but have not really described what a legacy system actually is . In my conferences too I am asked to just exactly define a … Continue reading Legacy Telecom Networks
We have seen the evolution of teelcom access networks through generations happening pretty quickly recently. While earlier it was a decade that led to the jump between generations, the recent jumps from 3G to 4G to 5G happening fairly quickly. In this article let us dive into what enhancements went into 2G and its successor 3G, since
Where 2G is referred to as the GSM era , 2.5 G as the GPRS with GSM era. The following two diagram denote the service operators architecture nodes in both these times .
2G / GSM era
As compared to its predecessor 1G which used FDMA ( Frequency Division Multiplexing ) for channelization , 2G used used TDMA and CDMA for dividing the channels .
Note that in pure 2G there was only circuit switched communication services .
2.5G or GPRS era
The advent of 2.5 G, in later part of 1990s, bought packet switching for data access along with existing circuit switching for voice network. While 1G and pure2G relied solely on circuit switching, now 2.5 G used both circuit switched and packet switching. The speed provided by General Packet Radio Service ( GPRS ) was ~= 50 Kbps.
Digital voice was introduced with multiple access technologies like CDMS ( Core Division Multiple access )
2.75G ( EDGE)
EDGE( Enhanced Data Rates for GSM evolution) was deploying on GSM technologies and was also standardised by 3GPP technologies . EDGE delivers higher bit-rates per radio channel, resulting in a threefold increase in capacity and performance compared with an ordinary GSM/GPRS connection with speed upto 1 Mbps.
In terms of transmission techniques, EDGE and its varients used Gaussian minimum-shift keying (GMSK), EDGE uses higher-order PSK/8 phase shift keying (8PSK) for the upper five of its nine modulation and coding schemes.
Note that the processes such as billing etc had begun merging for both the circuit switched and packet switched networks .
3G
Even though 2G evolution was enough to sustain voice abd video calls, the mobile industry became “smarter” and data hungry for faster services ( mobile gaming , video conferencing ,video streaming, social media interactions are some of the usecases ). It became necessary to bring in faster speed while evolving towards and hence was born 3G in early 20000. Some of the tecehnolgies which were branded 3G are
UMTS (Universal Mobile Telecommunications System)
Core technology for 3G ,
CDMA2000
3.5G ( HSPA)
Now 3G was further succeeded by 3.5G ( HSPA – High Speed Downlink Packet Access ) with max theoritical 21.6 Mbps.
Eventually 4G ( LTE Long Term Evolution ) overtook the indutry with newer technologies but the impressive array of technologies in transaition between 2G to 3G to 4G was awe inspirinig indeed .
LTE stands for Long Term Evolution and is a registered trademark owned by ETSI (European Telecommunications Standards Institute) for the wireless data communications technology and a development of the GSM/UMTS standards.
striking features of 5G –
entirely IP based
ability to connect 100x more devices ( IOT favourable )
speed upto 10 Gbit/s
high peak bit rate
high data volume per unit area
virtually 0 latency hence high response time
