What is multiframe and multiframe control?

What is multiframe and multiframe control?

The 26 traffic multiframe structure is used to send information on the traffic channel. The 26 traffic multiframe structure is used to combine user data (traffic), slow control signaling (SACCH), and an idle time period. The time interval of a 26 frame traffic multiframe is 6 blocks of speech coder data (120 msec).

What is GSM frame structure?

The GSM frame structure is designated as hyperframe, superframe, multiframe and frame. The minimum unit being frame (or TDMA frame) is made of 8 time slots. One GSM hyperframe composed of 2048 superframes. Each GSM superframe composed of multiframes (either 26 or 51 as described below).

Which is the correct GSM hierarchy of frames?

GSM Time Hierarchy is also known as GSM Frame Hierarchy. In GSM, frequency band of 25 MHz is divided into 200 KHz of smaller bands. Each carry one RF carrier, this gives 125 carriers. As one carrier is used as guard channel between GSM and other frequency bands 124 carriers are useful RF channels.

What is the frame rate of GSM?

A GSM Multiframe is the basic unit, and is 120 ms long. There are 26 Frames in each Multiframe, with each Frame being 4.61538 ms long (120 ms/26). Within each Frame are 8 Timeslots at 576.92 μs per Timeslot (577 μs in round numbers). Finally, there are 156.25 Bits per Timeslot, each Bit being 3.69231 μs long.

Which frames of control multiframe carries BCCH data?

The 51-frame Control Channel Multiframe (BCCH/CCCH) This is fairly obvious because RACH is the only control channel in the BCCH/CCCH group which works in the uplink direction.

How many frames are there in traffic multiframe and control multiframe respectively?

At the center of the 26-frame traffic channel multiframe (i.e, Frame 12) is the Slow Associated Control Channel (SACCH) which carries link control information to and from the MS–BTS. At the last frame is 1 idle frame.

What is GSM burst?

The slot is then the time that is allocated to the particular user, and the GSM burst is the transmission that is made in this time. Each GSM slot, and hence each GSM burst lasts for 0.577 mS (15/26 mS). Eight of these burst periods are grouped into what is known as a TDMA frame.

What is TDMA frame?

TDMA requires a centralized control node, whose primary function is to transmit a periodic reference burst that defines a frame and forces a measure of synchronization of all the users. The frame so-defined is divided into time slots, and each user is assigned a Time Slot in which to transmit its information.

What are the different channels used in GSM?

In GSM logical channels (see Figure 7.4) are used to carry traffic and control information. There are three types of logical channels: traffic channels (TCHs), control channels (CCHs), and the cell broadcast channel (CBCH). The traffic channels are used to transmit user information (speech or data).

What is the duration of a super frame?

Superframe Structure In a superframe (see Figure 20.9), a dedicated PAN coordinator transmits superframe beacons in predetermined intervals. These intervals can be as short as 15 ms or as long as 245 seconds. The time between two beacons is divided into 16 equal time slots independent of the duration of the superframe.

How many time slots in GSM frame has?

8 time slots
The GSM standard [1] specifies a TDMA frame as a combination of 8 time slots. Each time slot has a duration of 3/5200 seconds (about 0.577 ms) and a time slot number (TN) from 0 to 7. GSM frames use GMSK modulation, where one symbol is equivalent to one bit. Each time slot is 156.25 bits long.

How many types of burst are there in GSM?

Five different types
Burst Structure Five different types of bursts are used for transmission in GSM. The normal burst is used to carry data and most signaling.

What is the structure of a GSM multiframe?

There are several GSM multiframe structures: Traffic multiframe: The Traffic Channel frames are organised into multiframes consisting of 26 bursts and taking 120 ms. In a traffic multiframe, 24 bursts are used for traffic.

How are the channels organized in a multiframe?

Traffic multiframe: The Traffic Channel frames are organised into multiframes consisting of 26 bursts and taking 120 ms. In a traffic multiframe, 24 bursts are used for traffic. These are numbered 0 to 11 and 13 to 24. One of the remaining bursts is then used to accommodate the SACCH, the remaining frame remaining free.

How are data frames organized in GSM primer?

GSM data structure is split into slots, frames, multiframes, superframes and hyperframes to give the required structure and timing to the transmitted data. GSM primer includes: The data frames and slots within 2G GSM are organised in a logical manner so that the system understands when particular types of data are to be transmitted.

What is the counter in the GSM hyperframe?

Within the GSM hyperframe there is a counter and every time slot has a unique sequential number comprising the frame number and time slot number. This is used to maintain synchronisation of the different scheduled operations with the GSM frame structure. These include functions such as: