You have to understand at least the structure of slot, frame, multiframe (Do you remember where the multiframe is located in overall GSM frame structure?. This page on GSM tutorial covers GSM frame structure including concept of slot, frame,multiframe,superframe and hyperframe. It covers both 51 frame multiframe . Global System for Mobile (GSM) Several providers can setup mobile networks following the GSM .. Control Channel Multiframe (Reverse link for TS0). 0. F. 1.
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Do you remember where the multiframe is located in overall GSM frame structure? The first time-slot Slot-0 of the base-frequency TDMA is used as the base-control channel or beacon channel.
Multirfame user uses the slot 2 at every frame and the mutliframe user use the slot 4 at every frame. Wednesday, 2 April Structure of Multi-Frame. The use of the superframe time period allows all mobile devices to scan all the different time frame types at least once. Each GSM superframe composed of multiframes either 26 or 51 as described below. Multiframes are frames that are grouped or linked together to perform specific functions.
Examples shown above was a kind of simplified illustration for isolated channels e.
Now each RF carrier will have eight time slots. Build More-Effective Smart Devices: Every time slot during a hyperframe has a sequential number represented by an 11 bit counter that is composed of a frame number and a time slot number.
By Multuframe Morgan at April 02, This tutorial section on GSM basics covers following sub topics: They should also understand mapping of different channels to time slots in these gsm frame structures.
The illustration below is for Downlink multiframe structure.
Why 26 and 51 Multiframes in GSM |
In simplified terms the base station transmits two types of channel, namely traffic and control. You will also discover how 2nd generation systems are gradually evolving into 3rd generation broadband multimedia systems.
Followings are a couple of video tutorial that I found mulhiframe YouTube which would greatly help you understand overall GSM frame and channel structure.
You have to understand at least the structure of slot, frame, multiframe structure in very detail. During voice communication, one user multifrsme typically assigned to each time slot within a frame. This time slot carries Do this questions and answer by yourself whenever you have chance until your brain automatically pops up a frame structure diagram as soon as you see some key words related to GSM frame.
I don’t find any way to visualize the whole Hyper Frame structure showing the details at the level of every single slots, but overal GSM frame hierarchy is as follows.
GSM Timeslot & Frequency Specifications
In this diagram, the second slot in each frame is jultiframe used as a control channel but it is not always the case. The GSM frame structure provides the basis for the various physical channels used within GSM, and accordingly it is at the heart of the overall system. In reality, all of those scheduling are combined to form a very complex table as shown in the following example. Following is the common example of a Traffic Multiframe.
The GSM allows a cell radius up to of 35 km. The GSM system also combines frames to form Multiframes. By establishing these schedules by multigrame use of a frame structure, both the mobile and the base station are able to communicate not only the voice data, but also signalling information without the various types of data becoming intermixed and both ends of the transmission knowing exactly what types of information are being transmitted.
GSM Frame Structure | Multiframe Superframe Hyperframe |
The downlink and uplink channels are staggered in order to give the mobile time to process the received message and formulate a response. This division time wise is called TDMA. Let’s refresh our memory. Mix of traffic and control channels depends on number of frequency gsk per BTS that is the capacity of a cell and the traffic patterns.
Multiframes on the GSM system use established schedules for specific purposes, such as coordinating with frequency hopping patterns. Sometimes you would notice what we did in the kindergarden still works very well when you are at the age when you have your multtiframe kindergarden kids -: Each frame composed of 8 time slots.
Following is the most basic scheduling for fundamental channels. You will see a better way to multifeame this structure at later section, for now just try to get some ‘sense feeling ‘ of how a multiframe looks like.