Different bursts are mapped to these channels uniquely as per gsm technical specification 05. As they tranverse between layers they map to other layer frames. Explained are the physical and logical radio channel structures of the gsm system along with the basic frame and slot structures. Global system for mobile gsm university of pittsburgh. Nu tek india limited traffic channels tch one physical channel 1 timeslot can support. Gsm owns a market share of more than 70 percent of the worlds digital cellular subscribers. To understand the mapping of the logical channels onto physical channels, it is good to understand the two dimensions in time used by the gsm frame structure for more details on the frame structure, see section 3. I understand the different types of channels common continue reading gsm logical vs physical channels. A system operator may choose to support less than seven paging channels. The physical channels are determined by the timeslot, whereas the logical channels are determined by the information carried within the physical channel. Gsm logical channels free download as powerpoint presentation. Aug 25, 2009 logical channels define what type of information is being transferred and transport channel defines how the information is being transferred. Physical uplink control channel an overview sciencedirect. February, 28th 2005 overview in this document i make a study of third mobiles generation systems.
Logical channels reside between radio link control rlc and medium access control mac layer. Physical channels, logical channels, network, and operation. In this tutorial different types of logical channels and transport channels and their mappings are described. Gsm logical vs physical channels this topic has 10 replies, 1 voice, and was last updated 9 years, 3 months ago by deepak. Physical channels, logical channels, network, and operation through a thorough description of key functional sections of a gsm network and how they communicate with each other, you will learn how and why gsm is evolving into 3rd generation broadband systems including gprs, edge, and. Physical uplink control channel pucch, used for uplink control information, which includes. Besides the tdma in the gsm dcs we have also the fdma technique gsm dcs is characterised by a hybrid access to the channel each frame of 8 physical channels are multiplexed in the frequency domain each frame is transmitted in a subband of 200 khz 124 carriers are available the last one is not used for limiting. As shown in the figure there are two main types of channels in the gsm. A paging channel is used by the cdma system to transmit overhead messages and mobile directed messages. Walsh codes 1 through 7 may be used for paging channels. Gsm architecture or structure defined various channels in the air interface or radio interface.
This topic has 10 replies, 1 voice, and was last updated 9 years, 3 months ago by deepak. Each timeslot on a carrier is referred to as a physical channel logical channel. As shown in the figure, there are three types of umts channels viz. Gsm is the name of a standardization group established in 1982 to create a common european mobile telephone standard.
Gsm channels in order to transmit information, we required the channels. Physical data channels are distinguished by the ways in which the physical channel processor manipulates them, and by the ways in which they are mapped onto the symbols and subcarriers used by orthogonal frequencydivision multiplexing ofdma. The scrambling code for the message part is chosen based on the preamble code. A physical channel may carry different messages, depending on the information that is to be sent.
One of those frequency channels is defined as the basefrequency beacon frequency or bcch frequency. Physical layer comparative study of wcdma and lte by affan ahmed master of science in electrical engineering san diego state university, 2012 the world of technology has always been completive and dynamic. Besides the tdma in the gsmdcs we have also the fdma technique gsmdcs is characterised by a hybrid access to the channel each frame of 8 physical channels are multiplexed in the frequency domain each frame is transmitted in a subband of 200 khz 124 carriers are available the last one is. Physical channels determine how data is processed and then mapped via dynamical scheduling onto resource blocks. To perform neighbour cell measurements, the tester features userdefinable lists for the gsm neighbour cells fig 1 and. Introduction to global system for mobile communication. Data channels data channels support a variety of data rates 2. There are broadly two categories of logical channels available. Logical channel type in gsm as we know, every cell has several trx and every trx includes 8 timeslots i. Physical channel types of lte the physical layer uses resource blocks to transmit binary coded information in qpks, 16qam or 64qam or ook modulation form.
Introduction to physical and logical channels tel3pedia. Gprs uses the same modulation and frame structure that is employed by gsm, and in this way it is an evolution of the gsm standard. At first i will center the study in the objectives and main characteristic of this generation. Physical channels, logical channels, network, and operation kindle edition by harte, lawrence. Umts channels logical,transport,physical umts channels. Traffic channels are used to send speech or data services. Global system for mobile communication gsm is a globally accepted standard for digital cellular communication. Described are the fundamental capabilities and operation of the gsm radio channel including channel coding, modulation types, speech coding, rf power control, and mobile assisted handover. Easily attend job interviews and college exams with these multiple choice questions. Global system for mobile communication gsm definition global system for mobile communication gsm is a globally accepted standard for digital cellular communication. Page 2 of 16 1 frequency bands and channels gsm global systems for mobile frequency bands are the radio spectra designated by the itu international telecommunications union for the operation of the gsm for mobile systems.
Gsm uses a variety of channels in which the data is carried. This tutorial on umts covers umts logical channels, transport channels and physical channels. These channels assist in call terminations and sms delivery. Physical, logical and control channels each have different functions as described below. In p25 phase 2, a physical channel is divided into two time slots or logical channels. Viewing 11 posts 1 through 11 of 11 total author posts 17th august 2008 at 14. Part 4 part 4 gsm gsm radio interface radio interface lecture 4. It is a highcapacity switch that provides functions such as handover, cell configuration. Half rate traffic channels at a net bit rate of 11. In the radio subsystem, the physical channel supports the logical channel based on the type of message transmitted.
Like transport channels, also physical channels are unidirectional. Introduction to global system for mobile communication gsm. Innovation in the wireless area however is not simply a matter of introducing new technology or adding new services. In summary, a physical radio channel is the frequency or frequency pair allocated by the regulatory body. In gsm, these channels are separated into physical channels and logical channels. Fdma parts involves the division by frequency of the 25 mhz bandwidth in to 124 carrier frequencies also called arfcn spaced 200 khz for gsm900. Channels and arfcn slightly different in other frequency bands a tdma frame is defined on the radio carrier 8 users per carrier channel rate is 270.
Radio channels, physical channels and logical channels. Umts logical channels and transport channels 3glteinfo. In p25 phase 1, a physical channel and logical channel are the same thing. In this case, unused codes may be assigned to traffic channels. Physical channels logical channels network functions and operation. Gprs physical and logical channels the gprs physical layer, e. In the us, gsm operates in the bands 850 mhz and 1900 mhz. Cell broadcast allows you to subscribe to local news channels mobile terminating fax another number you are issued with that receives faxes that you can then download to the nearest fax machine. Gsm network architecture, channelisation, signalling and. Bscthe bsc provides all the control functions and physical links between the msc and bts. Study and learn these interview mcq questions and answers on 2g gsm logical channels and types. Gsm is a circuitswitched system that divides each 200 khz channel into eight 25 khz timeslots. Download it once and read it on your kindle device, pc, phones or tablets.
Gsm and the gsm logo are trademarks registered and owned by the gsm association. Use features like bookmarks, note taking and highlighting while reading introduction to gsm. Introduction in telecommunications a channel, refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel. Logical channels define what type of information is being transferred and transport channel defines how the information is being transferred logical channels. Variety of information is transmitted between the ms and bts. For gsm1800 frequency spectrum of 75 mhz bandwidth is. Page 2 of 16 1 frequency bands and channels gsm global systems for mobile frequency bands are the radio spectra designated by the itu international telecommunications. Thus physical channels also in eutran represent the available physical resources.