Multislot Class
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A multislot class is an important part of a technical specification of a GPRS/EGPRS enabled mobile phone which primarily indicates the maximum number of radio timeslots that can be allocated to a mobile phone.
It indirectly determines the speed of data transfer in the Uplink and Downlink direction.
A multislot class can be a value between 1 to 45. The multislot class of a mobile phone can be found out by looking at the technical specifications of the mobile phone. Multislot class with values greater than 31 are referred to as high multislot classes.
The network uses the multislot class information for allocating radio channels in the uplink and downlink direction.
A multislot allocation can be represented for example like 5+2. The first number(5) is the number of downlink timeslots and the second number is the number of uplink timeslots allocated to the mobile station.
A commonly used multislot class is class 10 for many GPRS/EGPRS mobiles. A class 10 mobile uses a maximum of 4 timeslots in downlink direction and 2 timeslots in uplink direction. However simultaneously a maximum number of 5 simultaneous timeslots can be used in both uplink and downlink. The network will automatically configure the for either 3+2 or 4+1 operation depending on the nature of data transfer.
Some high end mobiles, usually also supporting UMTS also support GPRS/EDGE multislot class 32. According to 3GPP TS 45.002 (Release 6), Table B.2, mobile stations of this class support 5 timeslots in downlink and 3 timeslots in uplink with a maximum number of 6 simultaneously used timeslots. If data traffic is concentrated in downlink direction the network will configure the connection for 5+1 operation. When more data is transferred in the uplink the network can at any time change the constellation to 4+2 or 3+3. Under the best reception conditions, i.e. when the best EDGE modulation and coding scheme can be used, 5 timeslots can carry a bandwidth of 5*59.2 kbit/s = 296 kbit/s. In uplink direction, 3 timeslots can carry a bandwidth of 3*59.2 kbit/s = 177.6 kbit/s.[1]
[edit] Attributes of a multislot class
Each multislot class identifies the following:- a)the maximum number of Timeslots that can be allocated on uplink b)the maximum number of Timeslots that can be allocated on downlink c)the total number of timeslots which can be allocated by the network to the mobile d) TTa : the time needed for the mobile phone to perform adjacent cell signal level measurement and get ready to transmit e) TTb :the time needed for the MS to get ready to transmit f)TRa : the time needed for the MS to perform adjacent cell signal level measurement and get ready to receive g) TRb :the time needed for the MS to get ready to receive.
The different multislot class specification is detailed in the Annex B of the 3GPP Technical Specification 45.002 (Multiplexing and multiple access on the radio path)