Unit - 4
Second Generation Mobile Networks-GSM
Throughout the evolution of cellular telecommunications, various systems have been developed without the benefit of standardized specifications. This presented many problems directly related to compatibility, especially with the development of digital radio technology. The GSM standard is intended to address these problems
Global system for mobile communication (GSM) is a globally accepted standard for digital cellular communication. GSM is the name of a standardization group established in 1982 to create a common European mobile telephone standard that would formulate specifications for a pan-European mobile cellular radio system operating at 900 MHz.
The basic requirement of GSM has been described in five aspects
1 Services
2 Quality of services and security
3 radio frequency utilization
4 Network
5 Cost
GSM Services & Features
The system will provide service portability that is mobile stations (MSs) or mobile phone can be used in all participating countries. The system will offer services that exist in the wire line network as well as service specifies to mobile communication.
Basic Services
1 Voice services
2 Data Services
3 Short Message Services
GSM voice service started as a full rate voice service that allowed 8 users per GSM radio channel. The original design allowed for the use of a half rate voice service (lower quality audio) to increase the number of simultaneous GSM voice users to 16 per radio channel.
GSM Data services support two data service groups short message services & bearer services.
The GSM short message service (SMS) provides a connectionless transfer of message with low-capacity & low-time performance. Every GSM short message can contain up to 140 octets or 160 characters of GSM default alphabet as defined in GSM.
The GSM barer services are similar ISDN services except that the maximum data rate is limited to 9.6Kbps. These services can be employed on notebook PCs or PDAs connected to the MS. Most mobile operator offer short message service as part of the basic subscription package.
Additional Services
GSM supports a comprehensive set of supplementary services that can complement and support both telephony and data services. Supplementary services are defined by GSM and are characterized as revenue-generating features.
1. Call forwarding—This service gives the subscriber the ability to forward incoming calls to another number if the called mobile unit is not reachable, if it is busy, if there is no reply, or if call forwarding is allowed unconditionally.
2. Barring of outgoing calls—This service makes it possible for a mobile subscriber to prevent all outgoing calls.
3. Barring of incoming calls—This function allows the subscriber to prevent incoming calls. The following two conditions for incoming call barring exist: baring of all incoming calls and barring of incoming calls when roaming outside the home PLMN.
4. Advice of charge (AoC)—The AoC service provides the mobile subscriber with an estimate of the call charges. There are two types of AoC information: one that provides the subscriber with an estimate of the bill and one that can be used for immediate charging purposes. AoC for data calls is provided on the basis of time measurements.
5. Call hold—This service enables the subscriber to interrupt an ongoing call and then subsequently re-establish the call. The call hold service is only applicable to normal telephony.
6. Call waiting—This service enables the mobile subscriber to be notified of an incoming call during a conversation. The subscriber can answer, reject, or ignore the incoming call. Call waiting is applicable to all GSM telecommunications services using a circuit-switched connection.
7. Multiparty service—The multiparty service enables a mobile subscriber to establish a multiparty conversation—that is, a simultaneous conversation between three and six subscribers. This service is only applicable to normal telephony.
calling line identification presentation/restriction—These services supply the called party with the integrated services digital network (ISDN) number of the calling party. The restriction service enables the calling party to restrict the presentation. The restriction overrides the presentation.
8. Closed user groups (CUGs)—CUGs are generally comparable to a PBX. They are a group of subscribers who are capable of only calling themselves and certain numbers.
GSM Specifications
Before looking at the GSM specifications, it is important to understand the
following basic terms:
bandwidth—the range of a channel's limits; the broader the
bandwidth, the faster data can be sent
• bits per second (bps)—a single on-off pulse of data; eight bits are equivalent to one byte
• frequency—the number of cycles per unit of time; frequency is measured in hertz (Hz)
• kilo (k)—kilo is the designation for 1,000; the abbreviation kbps represents 1,000 bits per second
• megahertz (MHz)—1,000,000 hertz (cycles per second)
• milliseconds (ms)—one-thousandth of a second
• watt (W)—a measure of power of a transmitter
Key takeaway
Global system for mobile communication (GSM) is a globally accepted standard for digital cellular communication. GSM is the name of a standardization group established in 1982 to create a common European mobile telephone standard that would formulate specifications for a pan-European mobile cellular radio system operating at 900 MHz.
Fig.1 GSM Architecture
In this architecture, a mobile station (MS) communicates with a base station system (BSS) through the radio interface. The BSS is connected to the network and switching subsystem (NSS) by communicating with a mobile switching centre (MSC).
The Switching System
The switching system (SS) is responsible for performing call processing and subscriber-related functions. The switching system includes the following functional units:
• Home location register (HLR)—The HLR is a database used for storage and management of subscriptions. The HLR is considered the most important database, as it stores permanent data about subscribers, including a subscriber's service profile, location information, and activity status. When an individual buys a subscription from one of the PCS operators, he or she is registered in the HLR of that operator.
• mobile services switching center (MSC)—The MSC performs the telephony switching functions of the system. It controls calls to and from other telephone and data systems. It also performs such functions as toll ticketing, network interfacing, common channel signaling, and others.
• visitor location register (VLR)—The VLR is a database that contains temporary information about subscribers that is needed by the MSC in order to service visiting subscribers. The VLR is always integrated with the MSC. When a mobile station roams into a new MSC area, the VLR connected to that MSC will request data about the mobile station from the HLR. Later, if the mobile station makes a call, the VLR will have the information needed for call setup without having to interrogate the HLR each time.
• authentication centre (AUC)—A unit called the AUC provides authentication and encryption parameters that verify the user's identity and ensure the confidentiality of each call. The AUC protects network operators from different types of fraud found in today's cellular world.
• equipment identity register (EIR)—The EIR is a database that contains information about the identity of mobile equipment that prevents calls from stolen, unauthorized, or defective mobile stations.
The AUC and EIR are implemented as stand-alone nodes or as a combined AUC/EIR node.
The Base Station System (BSS)
All radio-related functions are performed in the BSS, which consists of base station controllers (BSCs) and the base transceiver stations (BTSs).
• BSC—The BSC provides all the control functions and physical links between the MSC and BTS. It is a high-capacity switch that provides functions such as handover, cell configuration data, and control of radio frequency (RF) power levels in base transceiver stations. A
number of BSCs are served by an MSC.
• BTS—The BTS handles the radio interface to the mobile station. The BTS is the radio equipment (transceivers and antennas) needed to service each cell in the network. A group of BTSs are controlled by a BSC
-Mobile station (MS) – The MS consist of two parts the SIM (subscriber identity module) and the ME (mobile equipment)
An SIM can be
- A smart card, usually size of credit card
- A smaller sized ‘plug-in SIM” that can be broken out of it
The SIM is protected by a personal identity number (PIN) between four to eight digits in length. The PIN is loaded by a network operator at subscription time.
A SIM contain the subscriber-related information, including the PIN & PUK (PIN unblocking key) codes.
The ME contain the noncustomer-related hardware & software specific to the radio interface. When the SIM is removed from an MS the remaining ME cannot be used for reaching the services, except from emergency call.
This SIM-ME design supports portability as well as enhancing security. Usually, the ME is the property of subscriber.
Listed below is a description of the specifications and characteristics for GSM.
• frequency band—The frequency range specified for GSM is 1,850 to 1,990 MHz (mobile station to base station).
• duplex distance—The duplex distance is 80 MHz. Duplex distance is the distance between the uplink and downlink frequencies. A channel
has two frequencies, 80 MHz apart.
• channel separation—The separation between adjacent carrier
frequencies. In GSM, this is 200 kHz.
• modulation—Modulation is the process of sending a signal by
changing the characteristics of a carrier frequency. This is done in GSM
via Gaussian minimum shift keying (GMSK).
• transmission rate—GSM is a digital system with an over-the-air bit
rate of 270 kbps.
• access method—GSM utilizes the time division multiple access
(TDMA) concept. TDMA is a technique in which several different calls
may share the same carrier. Each call is assigned a particular time slot.
• speech coder—GSM uses linear predictive coding (LPC). The purpose
of LPC is to reduce the bit rate. The LPC provides parameters for a
filter that mimics the vocal tract. The signal passes through this filter,
leaving behind a residual signal. Speech is encoded at 13 kbps.
The operation of the GSM system can be understood by studying the sequence of events that takes place when a call is initiated from the Mobile Station.
Call from Mobile Phone to PSTN:
When a mobile subscriber makes a call to a PSTN telephone subscriber, the following sequence of events takes place:
Call from PSTN to Mobile Phone:
When a PSTN subscriber calls a mobile station, the sequence of events is as follows:
Location tracking and call setup
- The current location of an MS is maintained by a two-level hierarchical strategy with the HLR and the VLR.
- For example, the registration process of the MS moving from one VLR to another VLR is illustrated in Figure below
Fig 2 The MS Registration Process
Step 1. The MS periodically listens to the BCCH broadcast from the BSS.
Step 2. The new VLR communicates with the old VLR to find the HLR of the MS.
Step 3. The new VLR sends a registration message to the HLR.
Step 4. The new VLR informs the MS of the successful registration.
Step 5. The HLR sends a deregistration message to the old VLR.
Call Setup
The radio network consists of a large number of BTSs. Each BTS is given an identity. These BTSs are grouped according to location area, also given an identity. Each MSC/VLR (Mobile Services Switching Center/Visitor Location Register) serves the BTSs in an number of location areas. The GSM phones reports to the network (VLR) when it moves from a BTS in oneLocation Area to a BTS in another location area
The VLR always knows in which location area the GSM subscriber is located in at any given moment. Accordingly, the HLR always knows which MSC/VLR the GSM subscriber is at as well. Then, the GSM subscriber’s telephone number tells the network which HLR the actual GSM subscriber belongs to.
How a Call Gets to a GSM Mobile Phone
The call is routed through the telephone network to the closest MSC to the called GSM subscriber. Next, Gateway MSC checks with HLR, asking “Where is the GSM subscriber?” After that, the call is established to the actual MSC/VLR (Visiting MSC) either directly or through the fixed or international telephone network. Finally, the request for a mobile call is transmitted over all BTSs in the actual location area of the called GSM subscriber. Mobile recognizes its own identity, and the call begins.
Fig 3 Call Set Up
Key takeaway
The radio network consists of a large number of BTSs. Each BTS is given an identity. These BTSs are grouped according to location area, also given an identity. Each MSC/VLR (Mobile Services Switching Center/Visitor Location Register) serves the BTSs in a number of location areas. The GSM phones reports to the network (VLR) when it moves from a BTS in one Location Area to a BTS in another location area.
Data services over 2G networks -GSM
High-speed circuit-switched data (HSCSD)
General Packet Radio Service (GPRS)
Enhanced Data Rate for GSM Evolution (EDGE)
HSCSD
Features
1. High speed circuit switched data technology gives four times faster compare to typical GSM networks.
2. 38.8 kbps speed for all type of non-voice application.
3. It works with multiple slot which makes allow for data transmission at higher rate.
4. With all standard conditions (UL, DL) user can attain 40 to 57.4 kbps in specific area.
GPRS
Fig 4 GPRS network (1)
Fig 5: GPRS Network (2) (by Peter Rysavy)
Working of GPRS
It manages to send and receive of packet data to and from MS. It is useful for keeping track of mobile devices within scope of service area. It works in mobility management subscribed user verification and provides data required for billing.
It has vital role of routing information whichever is necessary for tunneling Protocol Data Unit (PDUs). To SGSN to Serve Distinct MS. It is on interface for external PDNs. i.e., public data units like internet and X.25.
Charging gateway
GTP
GPRS tunneling protocol uses to encapsulate IP or X.25 packet which are transferred among SGSN and GGSN.
Application of GPRS
GPRS provides many functions among several applications. These are listed below:
EDGE
Enhanced Data rates for Global Evolution (EDGE) introduces a new modulation technique, as well as protocol enhancements for transmitting packets over the radio.
The use of the new modulation and the protocol enhancements, result in dramatically increased throughput and capacity gains enabling 3G services in the existing GSM/GPRS networks. No changes are needed to the existing core network infrastructure to support EDGE. This emphasizes the fact that EDGE is only an “add-on” for BSS.
For EDGE, nine Modulation and Coding Schemes (MCS) are introduced (MCS1 to MCS9) and optimized for different radio environment. Four EDGE coding schemes are using GMSK and five are using 8 PSK Modulation.
Up gradation to EDGE
Benefits of EDGE
What EDGE Would Mean to Subscribers
Key takeaway
In early 2000, only a small portion of GSM subscribers used data services because existing GSM systems do not support easy access, high data rate and attractive prices. GSM operators must offer better services to stimulate the demand. The solution is General Packet Radio Service (GPRS). GPRS reuses the existing GSM infrastructure to provide end-to-end packet-switched services.
GPRS (General Packet Radio Service) is a packet-based communication service for mobile devices that allows data to be sent and received across a mobile telephone network. GPRS is a step towards 3G and is often referred to as 2.5G.
Here are some key benefits of GPRS
Speed
GPRS is packet switched. Higher connection speeds are attainable at around 56–118 kbps, a vast improvement on circuit switched networks of 9.6 kbps. By combining standard GSM time slots theoretical speeds of 171.2 kbps are attainable. However, in the very short term, speeds of 20-50 kbps are more realistic.
Always on connectivity
GPRS is an always-on service. There is no need to dial up like you have to on a home PC for instance. This feature is not unique to GPRS but is an important standard that will no doubt be a key feature for migration to 3G. It makes services instantaneously available to a device.
New and Better applications
Due to its high-speed connection and always-on connectivity GPRS enables full Internet applications and services such as video conferencing straight to your desktop or mobile device. Users are able to explore the Internet or their own corporate networks more efficiently than they could when using GSM. There is often no need to redevelop existing applications.
GSM operator Costs
GSM network providers do not have to start from scratch to deploy GPRS. GPRS is an upgrade to the existing network that sits alongside the GSM network. This makes it easier to deploy, there is little or no downtime of the existing GSM network whilst implementation takes place, most updates are software so they can be administered remotely and it allows GSM providers to add value to their business at relatively small costs. The GSM network still provides voice and the GPRS network handles data, because of this voice and data can be sent and received at the same time
Key takeaway
GPRS (General Packet Radio Service) is a packet-based communication service for mobile devices that allows data to be sent and received across a mobile telephone network. GPRS is a step towards 3G and is often referred to as 2.5G.
GPRS architecture works on the same procedure like GSM network, but, has additional entities that allow packet data transmission. This data network overlaps a second-generation GSM network providing packet data transport at the rates from 9.6 to 171 kbps. Along with the packet data transport the GSM network accommodates multiple users to share the same air interface resources concurrently.
Following is the GPRS Architecture diagram:
Fig 6 GPRS Architecture
GPRS attempts to reuse the existing GSM network elements as much as possible, but to effectively build a packet-based mobile cellular network, some new network elements, interfaces, and protocols for handling packet traffic are required.
GPRS Mobile Stations
New Mobile Stations (MS) are required to use GPRS services because existing GSM phones do not handle the enhanced air interface or packet data. A variety of MS can exist, including a high-speed version of current phones to support high-speed data access, a new PDA device with an embedded GSM phone, and PC cards for laptop computers. These mobile stations are backward compatible for making voice calls using GSM.
GPRS Base Station Subsystem
Each BSC requires the installation of one or more Packet Control Units (PCUs) and a software upgrade. The PCU provides a physical and logical data interface to the Base Station Subsystem (BSS) for packet data traffic. The BTS can also require a software upgrade but typically does not require hardware enhancements.
When either voice or data traffic is originated at the subscriber mobile, it is transported over the air interface to the BTS, and from the BTS to the BSC in the same way as a standard GSM call. However, at the output of the BSC, the traffic is separated; voice is sent to the Mobile Switching Center (MSC) per standard GSM, and data is sent to a new device called the SGSN via the PCU over a Frame Relay interface.
GPRS Support Nodes
Following two new components, called Gateway GPRS Support Nodes (GSNs) and, Serving GPRS Support Node (SGSN) are added:
Gateway GPRS Support Node (GGSN)
The Gateway GPRS Support Node acts as an interface and a router to external networks. It contains routing information for GPRS mobiles, which is used to tunnel packets through the IP based internal backbone to the correct Serving GPRS Support Node. The GGSN also collects charging information connected to the use of the external data networks and can act as a packet filter for incoming traffic.
Serving GPRS Support Node (SGSN)
The Serving GPRS Support Node is responsible for authentication of GPRS mobiles, registration of mobiles in the network, mobility management, and collecting information on charging for the use of the air interface.
Internal Backbone
The internal backbone is an IP based network used to carry packets between different GSNs. Tunnelling is used between SGSNs and GGSNs, so the internal backbone does not need any information about domains outside the GPRS network. Signalling from a GSN to a MSC, HLR or EIR is done using SS7.
Routing Area
GPRS introduces the concept of a Routing Area. This concept is similar to Location Area in GSM, except that it generally contains fewer cells. Because routing areas are smaller than location areas, less radio resources are used While broadcasting a page message.
Key takeaway
Therefore, GPRS requires modifications to numerous GSM network elements as summarized below:
GSM Network Element | Modification or Upgrade Required for GPRS. |
Mobile Station (MS) | New Mobile Station is required to access GPRS services. These new terminals will be backward compatible with GSM for voice calls. |
BTS | A software upgrade is required in the existing Base Transceiver Station (BTS). |
BSC | The Base Station Controller (BSC) requires a software upgrade and the installation of new hardware called the packet control unit (PCU). The PCU directs the data traffic to the GPRS network and can be a separate hardware element associated with the BSC. |
GPRS Support Nodes (GSNs) | The deployment of GPRS requires the installation of new core network elements called the serving GPRS support node (SGSN) and gateway GPRS support node (GGSN). |
Databases (HLR, VLR, etc.) | All the databases involved in the network will require software upgrades to handle the new call models and functions introduced by GPRS. |
To exchange data packets with external PDNs after a successful GPRS attach, a mobile station must apply for an address used in the PDN. In general, this address is called PDP
address (Packet Data Protocol address). In case the PDN is an IP network, this will be an IP address.
For each session, a so-called PDP context is created, which describes the characteristics of the session. It contains the PDP type (e.g., IPv4), the PDP address assigned to the mobile station (e.g., an IP address), the requested QoS class, and the address of a GGSN that serves as the access point to the external network. This context is stored in the MS, the SGSN, and the GGSN. Once a mobile station has an active PDP context, it is "visible" for the external network and can send and receive data packets. The mapping between the two addresses (PDP ~ GSM address) makes the transfer of data packets between MS and GGSN possible.
The allocation of a PDP address can be static or dynamic. In the first case, the mobile station permanently owns a PDP address, which has been assigned by the network operator of the user's home-PLMN. Using a dynamic addressing concept, a PDP address is assigned upon activation of a PDP context; i.e., each time a mobile station attaches to the network it will in general get a new PDP address, and after its GPRS detach this PDP address will be again available to other MSs. The PDP address can be assigned by the user's home-PLMN operator (Dynamic Home-PLMN PDP Address) or by the operator of the visited network (Dynamic Visited-PLMN PDP Address). The GGSN is responsible for the allocation and deactivation of the addresses.
The PDP context activation procedure initialized by the MS. Using the message activate pdp context request, the MS informs the SGSN about the requested PDP context. If a dynamic address is requested, the parameter pdp address will be left empty. Afterward, the usual GSM security functions (e.g., authentication of the user) are performed. If access is granted, the SGSN will send a create pdp context request to the affected GGSN. The GGSN creates a new entry in its PDP context table, which enables the GGSN to route data packets between the SGSN and the external PDN. It confirms this to the SGSN with a message create pdp context response, which also contains the dynamic PDP address
Data routing or routing of data packets to and fro from a mobile user, is one of the pivot requisites in the GPRS network. The requirement can be divided into two areas:
Data Packet Routing
The important roles of GGSN involve synergy with the external data network. The GGSN updates the location directory using routing information supplied by the SGSNs about the location of an MS. It routes the external data network protocol packet encapsulated over the GPRS backbone to the SGSN currently serving the MS. It also decapsulates and forwards external data network packets to the appropriate data network and collects charging data that is forwarded to a charging gateway (CG).
There are three important routing schemes:
The GPRS network encapsulates all data network protocols into its own encapsulation protocol called the GPRS tunnelling protocol (GTP). The GTP ensures security in the backbone network and simplifies the routing mechanism and the delivery of data over the GPRS network.
Mobility Management
The operation of the GPRS is partly independent of the GSM network. However, some procedures share the network elements with current GSM functions to increase efficiency and to make optimum use of free GSM resources (such as unallocated time slots).
An MS can be in any of the following three states in the GPRS system. The three-state model is unique to packet radio. GSM uses a two-state model either idle or active.
Active State
Data is transmitted between an MS and the GPRS network only when the MS is in the active state. In the active state, the SGSN knows the cell location of the MS.
Packet transmission to an active MS is initiated by packet paging to notify the MS of an incoming data packet. The data transmission proceeds immediately after packet paging through the channel indicated by the paging message. The purpose of the paging message is to simplify the process of receiving packets. The MS listens to only the paging messages instead of to all the data packets in the downlink channels. This reduces battery usage significantly.
When an MS has a packet to transmit, it must access the uplink channel (i.e., the channel to the packet data network where services reside). The uplink channel is shared by a number of MSs, and its use is allocated by a BSS. The MS requests use of the channel in a random access message. The BSS allocates an unused channel to the MS and sends an access grant message in reply to the random access message.
Standby State
In the standby state, only the routing area of the MS is known. (The routing area can consist of one or more cells within a GSM location area).
When the SGSN sends a packet to an MS that is in the standby state, the MS must be paged. Because the SGSN knows the routing area of the MS, a packet paging message is sent to the routing area. On receiving the packet paging message, the MS relays its cell location to the SGSN to establish the active state.
Idle State
In the idle state, the MS does not have a logical GPRS context activated or any Packet-Switched Public Data Network (PSPDN) addresses allocated. In this state, the MS can receive only those multicast messages that can be received by any GPRS MS. Because the GPRS network infrastructure does not know the location of the MS, it is not possible to send messages to the MS from external data networks.
Routing Updates
When an MS that is in an active or a standby state moves from one routing area to another within the service area of one SGSN, it must perform a routing update. The routing area information in the SGSN is updated, and the success of the procedure is indicated in the response message.
A cell-based routing update procedure is invoked when an active MS enters a new cell. The MS sends a short message containing the identity of the MS and its new location through GPRS channels to its current SGSN. This procedure is used only when the MS is in the active state.
The inter-SGSN routing update is the most complicated routing update. The MS changes from one SGSN area to another, and it must establish a new connection to a new SGSN. This means creating a new logical link context between the MS and the new SGSN and informing the GGSN about the new location of the MS.
Key takeaway
The GPRS network encapsulates all data network protocols into its own encapsulation protocol called the GPRS tunnelling protocol (GTP). The GTP ensures security in the backbone network and simplifies the routing mechanism and the delivery of data over the GPRS network.
Long Term Evolution (LTE)
The current dominant cellular transmission technology. Superseding 3G, LTE is a 4G technology that uses the GSM software infrastructure but different hardware interfaces. LTE/4G will coexist with 5G for some time.
Download speeds in the U.S. run the gamut from roughly 5 to 85 Mbps. Standardized in 2008, the first LTE smartphones appeared in 2011.
LTE provides global interoperability in more than three dozen frequency bands worldwide. However, no single phone supports all channels. Speed and other enhancements were made to the original LTE standard
LTE Is Based on IP Packets
In 3G and all prior cellular networks, voice was handled by the traditional circuit-switched network, and only data used the packet switched architecture of the Internet. However, LTE's Evolved Packet System (EPS) transmits both voice and data in IP packets. EPS comprises the OFDMA-based E-UTRAN air interface and
Evolved Packet Core (EPC).
In 2010, the ITU defined LTE, WiMAX and HSPA+ as 4G technologies. Previously, only LTE Advanced (LTE-A) was considered to be 4G. See LTE Advanced, LTE architecture, IP Multimedia Subsystem and 3GPP.
Wimax
WiMAX is one of the hottest broadband wireless technologies around today. WiMAX systems are expected to deliver broadband access services to residential and enterprise customers in an economical way. Loosely, WiMax is a standardized wireless version of Ethernet intended primarily as an alternative to wire technologies (such as Cable Modems, DSL and T1/E1 links) to provide broadband access to customer premises.
More strictly, WiMAX is an industry trade organization formed by leading communications, component, and equipment companies to promote and certify compatibility and interoperability of broadband wireless access equipment that conforms to the IEEE 802.16 and ETSI HIPERMAN standards.
WiMAX would operate similar to WiFi, but at higher speeds over greater distances and for a greater number of users. WiMAX has the ability to provide service even in areas that are difficult for wired infrastructure to reach and the ability to overcome the physical limitations of traditional wired infrastructure.
WiMAX was formed in April 2001, in anticipation of the publication of the original 10-66 GHz IEEE 802.16 specifications. WiMAX is to 802.16 as the WiFi Alliance is to 802.11.
WiMAX is such an easy term that people tend to use it for the 802.16 standards and technology themselves, although strictly it applies only to systems that meet specific conformance criteria laid down by the WiMAX Forum.
The 802.16a standard for 2-11 GHz is a wireless metropolitan area network (MAN) technology that will provide broadband wireless connectivity to Fixed, Portable and Nomadic devices.
It can be used to connect 802.11 hot spots to the Internet, provide campus connectivity, and provide a wireless alternative to cable and DSL for last mile broadband access.
WiMAX is expected to offer initially up to about 40 Mbps capacity per wireless channel for both fixed and portable applications, depending on the particular technical configuration chosen, enough to support hundreds of businesses with T-1 speed connectivity and thousands of residences with DSL speed connectivity. WiMAX can support voice and video as well as Internet data.
WiMax developed to provide wireless broadband access to buildings, either in competition to existing wired networks or alone in currently unserved rural or thinly populated areas. It can also be used to connect WLAN hotspots to the Internet. WiMAX is also intended to provide broadband connectivity to mobile devices. It would not be as fast as in these fixed applications, but expectations are for about 15 Mbps capacity in a 3 km cell coverage area.
With WiMAX, users could really cut free from today's Internet access arrangements and be able to go online at broadband speeds, almost wherever they like from within a MetroZone. WiMAX could potentially be deployed in a variety of spectrum bands: 2.3GHz, 2.5GHz, 3.5GHz, and 5.8GHz
4G
Fourth Generation Wireless Systems (4G)
What is 4G?
Motivation for 4G Research Before 3G Has Not Been Deployed?
Reasons to Have 4G
What's New in 4G?
Entirely packet-switched networks.
Need of 4G: -
Specification: -
Applications: -
Technique used in 4G:
Advantages and Disadvantages of 4G:
Advantages:
Disadvantages:
5G
What is 5G?
5G is the new technology in the field of cellular network. It is the technology with many advantages over the old generation of cellular networks. It is designed such that it will increase the speed, reduce error and make it more flexible for wireless communication. It can offer speeds up to 2Gbps.
Working of 5G
This technology has improved architecture and also utilises the spectrum which was unused in 4G. The technology called Multiple input and multiple output abbreviated as MIMO is employed. This has many transmitters and receivers so that large data can be transferred. It is not just limited to new radio spectrum. It will have a software platform for networking. It will provide advancements in virtualization, cloud-based technology. The business process automation allows the 5G to be flexible enough to provide easy user access any time.5G networks can create software-defined subnetwork constructs known as network slices. These slices enable network administrators to dictate network functionality based on users and devices.
Advantage of 5G
Key takeaway
References:
[1] Wireless Communications- Principles and Practice, T S Rappaport, Pearson Education India, Second Edition.
[2] Wireless Communication and Networks, Upen Dalal, Oxford university Press, First Edition, 2015.
[3] Wireless Communication and Networks 3G and Beyond, Iti Saha Misra, Tata
McGraw Hill Education Pvt. Ltd, Second Edition, 2009.
[4] Mobile Communication Engineering – Theory and Applications W C Y Lee, TMH Publication, Second Edition, 2008.
[5] Wireless Communication, Andrea Goldsmith, Cambridge University Press, 2005
[6] Fundamentals of Wireless Communication, David Tse and Pramod Viswanath,
Cambridge University Press, 2005
