DIFFERENCE OF GSM,UMTS,LTE & 5G

Feature	GSM	UMTS(3GSM)	LTE	5G NR
Technology	TDMA & FDMA	WCDMA	OFDMA	OFDMA
Generation	2G	3G	4G	5G
Encoding	Digital	Digital	Digital	Digital
Year of First Use	1991		2009	2018
Roaming	Worldwide, all countries except Japan and South Korea	Worldwide	Limited	Limited
Handset interoperability	SIM Card	SIM Card	SIM Card	SIM Card
Common Interference	Some electronics, e.g. amplifiers	None	None	None
Signal quality/coverage area	Good coverage indoors on 850/900 MHz. Repeaters possible. 35 km hard limit.	Smaller cells and lower indoors coverage on 2100 MHz; equivalent coverage indoors and superior range to GSM on 850/900 MHz.	Smaller cells and lower coverage on S band	Dense cell on millimeter waves
Frequency utilization/Call density	0.2 MHz = 8 timeslots. Each timeslot can hold up to 2 calls (4 calls with VAMOS) through interleaving.	5 MHz = 2 Mbit/s. 42Mbit/s for HSPA+. Each call uses 1.8-12 kbit/s depending on chosen quality and audio complexity.	20 MHz	400 MHz
Handoff	Hard	Soft	Hard	Hard
Voice and Data at the same time	Yes GPRS Class A	Yes	No(Data only) Voice possible through VoLTE or fallback to 2G/3G	No(Data only) Voice possible through VoLTE

Differences between GSM, CDMA, TDMA, EVDO, UMTS And HSPA+

Read the differences between various mobile technologies being used internationally: GSM, CDMA, TDMA, EVDO, UMTS and HSPA+. They form the core of wireless networks worldwide.

GSM (Global System for Mobile Communications)

GSM is a standard set developed by European Telecommunications Standards Institute (ETSI) to describe technologies for second generation (2G) digital cellular networks. The GSM standard is more improved after the development of third generation (3G) UMTS standard developed by the 3GPP. 

CDMA (Code Division Multiple Access)

CDMA is a channel access method used by various radio communication technologies. It should not be confused with the mobile phone standards called cdma One, CDMA2000 (the 3G evolution of cdma One) and WCDMA (the 3G standard used by GSM carriers), which are often referred to as simply CDMA, and use CDMA as an underlying channel access method.

TDMA (Time Division Multiple Access)

TDMA is a channel access method for shared medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot. This allows multiple stations to share the same transmission medium (e.g. radio frequency channel) while using only a part of its channel capacity. TDMA is used in the digital 2G cellular systems 2G cellular systems such as Global System for Mobile Communications (GSM), Personal Digital Cellular (PDC) and iDEN standard for cellular phones.

EVDO (Evolution-Data Optimized or Evolution-Data Only)

EVDO is a telecommunications standard for the wireless transmission of data through radio signals, typically for broadband Internet access. It uses multiplexing techniques including code division multiple access (CDMA) as well as time division multiplexing (TDM) to maximize both individual user's throughput and the overall system throughput. It has been adopted by many mobile phone service providers around the world – particularly those previously employing CDMA networks. EVDO was designed as an evolution of the CDA2000 standard that would support high data rates and could be deployed alongside a wireless carrier's voice services.

UMTS (Universal Mobile Telecommunications System)

UMTS is a third generation mobile cellular technology for networks based on the GSM standard. Developed by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the International Telecommunication Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing cdma One technology. UMTS employs Wideband Code Division Multiple Access (W-CDMA) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators. UMTS specifies a complete network system, covering the radio access network (UMTS Terrestial Radio Access Network, or UTRAN), the core network (Mobile Application Part, or MAP) and the authentication of users via SIM cards. The technology described in UMTS is sometimes also referred to as Freedom of Mobile Multimedia Access (FOMA) or 3GSM.

HSPA+, Or Evolved High-Speed Packet Access

HSPA or HSPA+ is a technical standard for wireless, broadband telecommunication. HSPA+ enhances the widely used WCDMA based 3G networks with higher speeds for the end user that are comparable to the newer LTE networks. HSPA+ was first defined in the technical standard 3GPP release 7 and expanded further in later releases. HSPA+ provides an evolution of High Speed Packet Access High Speed Packet Access provides data rates up to 168 Megabits per second (M bit/s) to the mobile device and 22 M bit/s from the mobile device.

ADVANTAGES OF LTE

Following are the advantages of LTE:

1. LTE network uses all IP network architecture. Due to this fact, it is dedicated for packet switched operations. It supports data as well voice. The voice can be transported using voice over LTE protocols (i.e. VOIP) and fall-back to legacy networks (i.e. 2G/3G). 
2. As LTE supports MIMO, higher data rate can be achieved. 
3. LTE uses SC-FDMA in the uplink and hence mobile terminals can have low power during transmissions and hence battery life can be enhanced on user side. 
4. As LTE downloads the files faster, connection with network gets released faster for each connection. This will decrease traffic load on the LTE network. 
5. LTE uses OFDMA in the downlink, it utilizes channel resources effectively. This increases total user capacity of the LTE network as different users utilize different channels to access the system. 
6. It does not take much time for user to open the browser and download high bandwidth movie. This increases user experience to a great extent. This is due to the fact that latency is very low in LTE. 
7. Due to improved architecture, handoff is smooth from one region to the other. This results into smooth data streaming without any interruption of on-going data transfer. 
8. Higher versions of LTE such as LTE advanced will further improve the performance of existing LTE standard based products. 

LTE BASIC CONCEPT

LTE employs orthogonal Frequency Division Mutiple Access(OFDMA) for downlink data transmission and Single Carrier FDMA(SC-FDMA) for uplink Transmission.

LTE SPEED TEST TROUBLE SHOOTING

For Download Detail Full Speed Test Trouble shooting manual Click here

If there is issue in LTE Speed Test on all the sectors of the site then
please verify following steps.

1. SINR is above the target value . i.e SINR>25db
2. SINR is not fluctuating.
3. RSRP is above the target value. i.e RSRP>75dbm
4.Modulation Scheme is 64QAM.
5.Resource Block assignmentsis much lower than 100 on all the sector of sites.


After verifying the following scenarios go to bad RF Environment SINR<5.

Check the resource block assignment in bad rf environment, if resource block is still less and same as beofre then repeat the test in the off peak hours.

If resource block assignment increase significantly than before then raise the issue for backend support.

If speed test is less in FTP Testing then check the best availible server and repeat the test.


Click here to download full manual.

LTE Frame Structure

LTE Radio Frames, LTE Slots and LTE Sub frames:

In this topic we will learn  lte frame structure, resource block in lte, lte uplink frame structure, lte tdd frame configuration, lte resource grid, number of samples in lte frame, lte symbol duration

LTE Radio Frames:

Radio Frames in LTE  are of two types.

There are two types of radio frame for LTE: 
1. frame structure is applicable to Frequency Division Duplex (FDD) 
2. frame structure is related to Time Division Duplex (TDD)


1. Frequency Division Duplex (FDD) is valid for both half duplex, and full duplex FDD modes. Type 1 radio frame has a duration 10 ms and consists of equally sized 20 slots each of 0.5 ms. A subframe comprises two slots, thus one radio frame has 10 sub‐frames. In FDD mode, half of the subframes are available for downlink, and the other half are available for uplink transmission in each 10 ms interval, where downlink and uplink transmission are separated in the frequency domain.

2. Time Division Duplex (TDD) radio frame is composed of two identical half‐frames, each one having a duration of 5 ms; each half‐frame is further divided into 5 subframes having a duration of 1ms; two slots of length 0.5 ms constitute a subframe which is not a special subframe. The special types of subframes are composed of three fields: Downlink Pilot Timeslot (DwPTS), GP (Guard Period) and Uplink Pilot Timeslot (UpPTS). Seven uplink-downlink configurations are supported with both types (10 ms and 5 ms) of downlink‐to‐uplink switch‐point periodicity. In 5m downlink‐to‐uplink switch‐point periodicity, special type of sub‐frames is used in both half‐frames, but it is not the case in 10 ms downlink‐to‐uplink switch‐point periodicity, special frame are used only in first half‐frame. For downlink transmission sub‐frames 0, 5 and DwPTS are always reserved. UpPTS and the sub‐frame next to the special sub‐frame are always reserved for uplink communication.

FDD mode bit rate calculation

The basic EUTRAN Radio Frame is 10 ms long.

The EUTRAN Radio Frame is divided into 20 slots, each one 0.5 ms long.

Always two slots together form a sub frame. The sub frame (1 ms) is the smallest time unit the scheduler assigns to physical channels.

In case of FDD there is a time offset between uplink and downlink transmission.

If TDD mode is used, sub frame 0 and sub frame 5 must be downlink, all other sub frames can dynamically be used as uplink or downlink period.

LTE Slot:

• 7 symbols with short cyclic prefix.

• 6 symbols with long prefix.

• EUTRAN combines OFDM symbols in so called resource blocks RB.

• A single resource block is always 12 consecutive subcarriers during one subframe (2 slots, 1 ms):

• 12 subcarriers * 15 kHz= 180 kHz

• It is the task of the scheduler to assign resource blocks to physical channels belonging to different users or for general system tasks.

• A single cell must have at least 6 resource blocks (72 subcarriers) and up to 110 are    possible (1320 subcarriers). 

• OFDM symbols are arranged in a 2 dimensional matrix called the resource grid:

•  –      One axis of the grid is the subcarrier index

•  –      The other axis is the time.

• Each OFDM symbol has its place in the resource grid. 

• Channel estimation based on reference symbols.

• Interpolation in time and frequency domain

• In  WCDMA common pilot channel (CPICH) was used for this (together with reference       symbols on DCH)

• Each OFDM symbol even within a resource block can have a different modulation        scheme.

• EUTRAN defines the following options:  QPSK, 16QAM, 64QAM.

• Not every physical channel will be allowed to use any modulation scheme: Control        channels to be using mainly QPSK.

• From the 3gpp specification:

• In general it is the scheduler that decides which form to use depending on carrier quality feedback information from the UE.

The LTE Slot carries:

OFDM Resource Block for LTE/EUTRAN

OFDM resource Grid for LTE/EUTRAN

OFDM resource Grid for LTE/EUTRAN

Channel Estimation

Modulation Schemes for LTE/EUTRAN

LTE bit rate calculation

       -1 Radio Frame = 10 Sub-frame

     LTE bit rate calculation

       -1 Sub-frame = 2 Time-slots

       -1 Time-slot = 0.5 ms (i.e 1 Sub-frame = 1 ms)

       -1 Time-slot = 7 Modulation Symbols (when normal CP length is used)

       -1 Modulation Symbols = 6 bits; if 64 QAM is used as modulation scheme

    Radio resource is manage in LTE as resource grid....

       -1 Resource Block (RB) = 12 Sub-carriers

    Assume 20 MHz channel bandwidth (100 RBs), normal CP

    Therefore, number of bits in a sub-frame

    = 100RBs x 12 sub-carriers x 2 slots x 7 modulation symbols x 6 bits

    = 100800 bits

   Hence, data rate = 100800 bits / 1 ms = 100.8 Mbps

  * If 4x4 MIMO is used, then the peak data rate would be 4 x 100.8 Mbps = 403 Mbps.

  * If 3/4 coding is used to protect the data, we still get 0.75 x 403 Mbps = 302 Mbps as data      rate.