A TS has duration of 3/5200 seconds (577 ms). Eight TSs shape a TDMA frame, with around 4.62 ms span. At the BTS the TDMA frame on the greater part of the radio recurrence directs in the downlink bearing are adjusted. The same applies to the uplink. 





The begin of a TDMA frame on uplink is, be that as it may, postponed by a settled time relating to three TS periods. The explanation behind this postponement is to permit a similar TS number to be utilized as a part of both uplink and downlink bearings without requiring the MS to get and transmit at the same time.


HYPERFRAMES, SUPERFRAMES AND MULTIFRAMES


The longest recurrent time period day and age of the structure is called hyperframe and has the span of 3 h 28 min 53 sec 760 ms. The TDMA Frame Numbers (FN) are numbered from 0 to 2 715 647. Such a long stretch is required for the support of cryptographic systems. 



One hyperframe is isolated into 2048 superframes, which have term of 6.12 seconds. 

The superframe is itself subdivided into multiframes. There are two sorts of multiframes in the framework: 

26 frame multiframe (51 for every superframe) with a term of 120 ms, containing 26 TDMA outlines. This multiframe is utilized to convey the sensible channels TCH, SACCH and FACCH, which are depicted in this section. 

51 frame multiframe (26 for every superframe) with a term of 235.4 ms, containing 51 TDMA outlines. This multiframe is utilized to convey the sensible channels FCCH, SCH, BCCH, CCCH, SDCCH, SACCH, and CBCH, which are depicted in this section.

BURST FORMATS
The bit rate over the air interface is 270.8 kbps. This gives a bit time of 3.692 s (48/13 s). The time interim of a TS therefore compares to 156.25 bits. The physical substance of a TS is known as a burst. There are five distinct sorts of blasts. A chart of these blasts is appeared in Figure 2-10. 

Normal Burst (NB): This burst is utilized to convey data on movement and control channels. For TCH it contains 114 scrambled bits, and incorporates a watch time of 8.25 piece length (30.46 s). The taking banner is important just for TCH, which is depicted in this section. 

Frequency redress Burst (FB): This burst is utilized for recurrence synchronization of the MS. It comprises of zeroes as it were. The redundancy of FBs is likewise named Frequency Correction CHannel (FCCH) which is portrayed in this section. 

Synchronization Burst (SB): This burst is utilized for time synchronization of the MS. It contains a long preparing succession and conveys the data of the TDMA Frame Number (FN) and Base Station Identity Code (BSIC). The redundancy of synchronization blasts is likewise called Synchronization CHannel (SCH) which is portrayed in this section. 

Access Burst (AB): This burst is utilized for arbitrary get to and handover get to. It is portrayed by a long protect period (68.25 piece term or 252 s), to cook for burst transmission from a MS that does not know the planning advance at the main get to (or at handover). This takes into consideration a cell span of 35 km. The get to blast is utilized on the Random Access CHannel (RACH) and on the Fast Associated Control CHannel (FACCH) at handover. 

Dummy Burst: This burst is transmitted on radio recurrence c0 when no other sort of burst is to be sent. This implies the construct station dependably transmits in light of the recurrence conveying the framework data, hence making it workable for the MSs to perform control estimations on the BTS keeping in mind the end goal to figure out which BTS to use for beginning access or which to use for handover. Keeping in mind the end goal to accomplish this, a fake page and a fake burst is characterized in the GSM suggestions. CCCH is supplanted by the fake page, when there is no paging message to transmit. This spurious page is a page to a non-existing MS. In alternate TSs not being utilized, a fake burst with a pre-characterized set of settled bits is transmitted.