Comparison Of Land Series And Mobile Phones
Comparison Of Land Series And Mobile Phones
No one can ever ignore Alexander Graham Bell, who’s credited as the inventor of “Telephone”. With innovation and improvement in technology, the simple two way communicating device has taken a new form popularly referred to as “cellular phone”. We’ve reached a time where it is very common to hear words like “I cannot live without mobile phone”. Cell phone has turned into a part of our daily life.. Allow it be business bargains, any personal work or meetings everything today can be carried out with the aid of mobile phone.
A Mobile Phone, CELLULAR PHONE or Hand Phone can be an electronic device which lets the user to be mobile and make or receive telephone calls across a wide geographical place, served by many public cells. The calls could possibly be made to and received from the fixed collection or another mobile. Mobile phone uses a wireless network for conversation i actually.e. a network which is usually which is not connected by cables of any kind.
Base Station (BS).Each base station is in turn is connected to a central hub and is usually manipulated by this switching business office, also referred to as Mobile Switching Middle (MSC). MSC is nothing else but a computerized center that’s accountable for connecting calls, recording call information and billing. The conversation between all of the base stations and calling central office is coordinated by MSC. PSTN connects all conventional phone switching centers with MSCs throughout the world.
Also, the cell size isn’t fixed and can be increased or decreased according to the population of the region. Generally, the radius is kept 1 to 12 mi. In comparison to low density areas, excessive density areas require additional geographically smaller cells to meet texas plural executive up the traffic demands. Once the cell is determined, the cell size is usually optimized in order that the adjacent cells signals are not interfered. For this function, the transmission power of every cell is kept low to prevent its transmission from interfering with those of different cells.
Block Diagram of cellular Network
Difference between Fixed Brand and Mobile Phone
In case of open public switched phone network (PSTN), the landline trunked lines (trunks) are being used for transfer of info. These trunks include fiber optic wires, copper cables, microwave links and satellite television links. The network configuration in the PSTN is usually practically static as the alterations in the network connections will be required only once the subscriber would transform the residence. Wireless networks, alternatively are highly dynamic, wherein the network construction is usually to be rearranged every time the subscriber moves in to the coverage region of brand-new base station. Unlike predetermined networks which are hard to change, wireless networks must reconfigure themselves for users within small intervals of period (on the fraction of seconds) to supply roaming and imperceptible handoffs between phone calls as a mobiles moves about. The available channel bandwidth for set networks could be increased by installing large capacity cables whereas cellular networks will be constrained by RF cellular bandwidth given for each user.
Frequency Reuse Principle
Increasing the capability and coverage area is the key feature of any cellular network and this can be achieved by re-using the frequency. It is true that in order to avoid interference, neighboring cells shouldn’t use same frequency but as the frequencies available is limited, they are often reused. A regularity reuse pattern is nothing else but a collection of N cells arranged along where N may be the reuse factor, in which each cell runs on the unique set of frequencies. The frequencies can be reused whenever the structure is repeated.
F1,F2, F3,and F4 in the above diagram define the design with the reuse issue of 4.The cells that use the same frequencies(ones with the same frequency number) are referred to as reusing cells.
Transmitting and Receiving Calls
Whenever user makes a phone from cellular phone, the mobile station looks for a band with a solid signal to setup a channel and send the info to the closest basic station using that channel. The bottom station afterward connects to Mobile phone Switching Center (MSC) and passes the data to it. MSC further more passes the data to the telephone central office. A connection is set up and result is sent back to MSC, if the known as party is available. At this time MSC assigns an unused tone of voice channel to the call and mobile station quickly adjusts its tuning to the brand new channel so that communication can take place.
Whenever a call is made to a cellular phone , the central workplace of calling from where the call up has been initiated sends the quantity to the MSC.MSC in turn sends the query signals to each cell in process to find out the location of mobile station. This technique is called paging. After the mobile station is available MSC transmits the ringing signal to it and after the station answers, a voice channel is assigned to the decision for the communication to begin with.
The procedure for transferring the connected or on going call from one channel to another in order to prevent the termination of call is known as Handoff or Handover. Whenever the mobile phone station moves from one cell to another and signal becomes fragile, handover is required. MSC monitors the level of signal every couple of seconds and if it finds the effectiveness of signal diminishing then it searches for a fresh cell wherein better communication may take place. There will be two types of handoff:
Hard Handoff: In cases like this, a mobile phone station communicates simply with one basic station. When the portable station moves from one cell to another, the bond with the target cell is established only once the connection from the foundation how to write a synthesis paper is broken. Thus, such handovers are also known as break-before-make.
Soft Handoff: In this case, a portable station can talk to two bottom stations so you don’t have of breaking from the source cell to generate a connection to a target cell. Instead, a mobile station may continue with a new connection while retaining the older one for a while. As a result, such handovers are known as make-before-break.
Frequency Division Multiple Gain access to (FDMA): FDMA is a method where the spectrum is split into frequencies and is designated to users. The channel is usually assigned to only 1 subscriber or user at a time i just.e. A channel will stay blocked before call which was at first made has completed. A “full duplex” FDMA requires two stations, one for mailing or transmitting the info and another for acquiring. FDMA technology was found in first generation systems, which were analog systems.
Time Division Multiple Gain access to (TDMA): TDMA splits
each frequency into time slots thus increasing spectrum capability. In TDMA technology, each customer is permitted to access the complete radio regularity channel for the short time of a phone. The same regularity channel can be shared by various other users as well at different time slots. The base station constantly switches from customer to consumer on the channel. The next generation portable cellular network is certainly dominated by TDMA.
Code Division Multiple Access (CDMA): CDMA easily means communicating with unique codes. It allows all the users to occupy all stations simultaneously consequently increasing the spectrum capability. Each voice or data call is assigned a unique code, so that calls could be differentiated from each other while staying carried over the same spectrum. In case of CDMA terminals can communicate with various base stations using the characteristic known as “soft hand-off”.
Mobile Generations: Development from 1G to 3G
With the rapid developments in technology and the greater collection of new wireless products and services and applications the mobile phone has grown through various generations fulfilling the increasing requirements of its users. First Generation (1G) mobile phones were analog which got simply voice facility. Additional services like messaging and data services, fax were launched in digital phones referred to as Second Generation (2G) cell phones. The third generation mobile phones (3G) which are staying talked about a lot nowadays, includes high rate of internet browsing, photo and video messaging services. In a nutshell, multimedia facilities when added to the second technology mobiles (2G) gave birth to the third Generation mobile phones.
First Generation Mobile Program: The cellular systems were introduced in 1980’s and since then it hasn’t stopped growing. The earliest generation mobiles were analog devices with the capability of transmitting at the quickness of 9.6 kbps max. In those days there was no world-wide coordination for the creation of technical standards global. AMPS (Advanced CELLULAR PHONE System) was invented in Bell Labs and was installed in USA in 1982.When used in England and Japan it was referred to as TACS and MCS-L1.In 1G mobile systems roaming was not possible and efficient usage of frequency spectrum was not there.
Second Generation Mobile System: ETSI was made in Europe in mid 1980s to standardize the mobile communication sector. This standardization result in the beginning of new network which was predicated on digital technology and popularly referred to as Global System for Mobile phone Connection (GSM).GSM was basically introduced to include more services to you see, the network together with meet the requirements of data visitors. GSM consists of the next three main components:
1. Basic Station Subsystem 2.Network Subsystem 3.Network Control System
Base Station Subsystem: It includes Base Transreceiver Station (BTS), Foundation Station Controller (BSC) and Transcoder sub-multiplexer (TCSM).BTS may be the network aspect that manages the user interface between cellular station and the network. Mobile terminals are linked to the BTS through the surroundings interface. BTS makes make use of omnidirectional or directional antennas for transmitting and reception. BSC provides major features like handover and managing radio information.
Network Subsystem: Network subsystem is basically an interface between the public network and GSM network. All the communication between mobile phone users and various other users (ISDN, fixed, mobile) is managed by NSS. The databases of subscriber and is also kept with NSS to control users mobility. Various components of NSS are referred to below:
1) Mobile Switching Centre (MSC): It is the most crucial component that performs switching capabilities essential for interconnections between portable users and different users (fixed or mobile).
2) GMSC: To connect the cellular network with PSTN, a gateway referred to as GMSC can be used.
3) Home Position Register (HLR): All of the information about the subscriber such as the coverage area, products and services provided to an individual, current location and mobile equipment status etc is taken care of in this register. The database remains same until the termination of subscription.
4) Visitor Area Register (VLR): The info of subscriber can be uploaded in this register whenever he enters the insurance policy coverage region to ensure that necessary services could be presented to him. VLR of the new region is updated with the data source whenever the subscriber moves to the brand new region. VLR is powerful in nature since it keeps the info of the subscriber temporarily and interacts with HLR for recording the data.
5) Authentication Center (AUC): It takes care of the secureness by providing requirements for encryption and authentication of users. Encryption main is kept in cellular equipment and also AUC to safeguard the network from unauthorized access.
6) Equipment Identity Register (EIR): All mobiles are determined using IMEI (International Mobile Equipment Identity) number which is written on the battery pack of the telephone. EIR keeps the set of all valid IMEI number and every time a call is initiated, the network checks the IMEI amount and call is connected if the number is valid. No cell phone calls are allowed from unauthorized terminals.
7) GSM Interworking Unit (GIWU): GIWU can be an element or a unit that is clearly a blend of hardware and software program and synchronizes the information. It lets the user to choose between concept and speech method by acting as an user interface to different networks.
Network Management System: The third element of GSM fundamentally monitors the different components and capabilities of the network. It performs the next main tasks:
1. Network Monitoring
2. Network Development
3. Network Measurement
4. Fault Management
NMS constantly monitors the performance of the network to ensure it runs easily. The performance could be measured by collecting the info from the individual components for analysis and keeping it in the data source. The network operator can then compare the info collected in the database with the one which was actually anticipated. If any fault takes place,
the fault alarm is certainly made .These faults are after that required to be corrected often by NMS or manually.
Interfaces in GSM
Different interfaces are being used in GSM. They are Air , Abis and A user interface.Air interface can be an interface between Portable station and Bottom Transreceiver Station (BTS),Abis connects Bottom Transreceiver Station (BTS) to Foundation Station Controller (BSC), and A interface is the one which is present between TCSM and MSC.
Value added services such as for example voice mail and short message services (sms) were put into GSM along with clever services like Pre-paid and fraud management. Down the road, GPRS (General Packet Radio Products and services) was introduced to ensure that packet switched data assistance could be offered. SGSN (Serving GPRS) and GGSN (Gateway GPRS) had been new elements which were introduced in the existing system so that packets could be delivered to air interface. IP routers, firewall servers and Domain brand servers were also used along with these components. Finally, to improve the data charge better coding strategies were used.
Third Generation Mobile System