PageOutline = GPRS and EDGE bit-rates =

This page tries to outline the possible achievable GPRS bit-rates.

There are multiple aspects that relate to the problem * channel coding, which in turn depends on * capabilities of the BTS and MS * performance of the radio channel * multi-slot operation, which depends on * capabilities of the BTS and MS * contention on the radio channel / resource sharing by multiple phones

channel coding

Depending on the characteristics of the radio channel (interference, bit errors, link quality, C/I), the network will
dynamically select the best coding scheme. The lower numbers (CS-1/MCS-1) have the most error coding and are very
resiliant but have little throughput. MCS-9 has no error correction coding at all, but t

=== GPRS channel coding ===

Each of the 8 GSM time-slots can operate i a number of different coding schemes:

	Coding Scheme		kbit/s
	CS-1		8.0
	CS-2		12.0
	CS-3		14.4
	CS-4		20.0

=== EDGE channel coding ===

Each of the 8 GSM time-slots can operate i a number of different coding schemes:

	Coding Scheme		kbit/s
	MCS-1		8.80
	MCS-2		11.20
	MCS-3		14.80
	MCS-4		17.60
	MCS-5		22.40
	MCS-6		29.60
	MCS-7		44.80
	MCS-8		54.54
	MCS-9		59.20

multi-slot capabilities

=== BTS side ===
BTS equipment is normally capable to run all timeslots in GPRS mode. If you're running a single-TRX small BTS, the first timeslot is always allocated for the BCCH/CCCH, leaving 7 time-slots available for voice (TCH) and data (PDTCH).

For example, a total of 7 time-slots in MCS-9 coding scheme would render
59.20 kbps * 7 = 414.40 kbps

=== MS side ===
On the MS (phone) side, things are not that simple. Normally, phones can not decode all 7/8 time-slots, as they operate in half-duplex mode and need some time for transmit, too. The capabilities of each phone are specified as so-called ''multislot class''

For a table of multislot classes, please see 3GPP TS 45.002, or a summarized version at [https://secure.wikimedia.org/wikipedia/en/wiki/GPRS#Multislot_Class wikipedia].

=== multi-slot class 10 ===
For example, a phone with EDGE multislot class 10 permits for a total of 5 active time-slots, which can be either 4+1 (4 downlink, 1 uplink) or (3+2) (3 uplink, 2 downlink).
Under ideal radio conditions (MCS-9), such a phone can thus reach the following two bit-rates:

	Coding Scheme		multislot		downlink		uplink
	MCS-9		4+1		236.80		59.20
	MCS-9		4+2		177.60		118.40

=== multi-slot class 32 ===

Coding Scheme

multislot

downlink

uplink