Key EVDO RF Parameter While Drive Test (DT)

RX:

It is the total signal level received within the bandwidth, including the serving carrier signal (C) and interfering signal (I).Those signals which are carried by other carrier are called interfering signals. The high value Rx does not necessarily come with strong carrier while low value Rx comes necessarily with weak carrier signals. It is mainly used for analysis of coverage area (weak coverage and strong coverage area).

C/I:

It is the Key parameter in EVDO drive test which helps to determine terminal data rate request forward rate. Where C shows the signal strength of serving sector and I shows the signal strength of the other available sectors .C/I and Ec/Io indicate the signal to noise ratio.

The relationship between C/I and Ec/Io is Ec/Io=C/C+I

Mapping Table:

DRC Index	Slots	Modulation	Preamble Chips	Payload Bits	Raw kb/s	C/I db
0x0	n/a	QPSK	n/a	0	Null rate	n/a
0x1	16	QPSK	1024	1024	38.4	-11.5
0x2	8	QPSK	512	1024	76.8	-9.2
0x3	4	QPSK	256	1024	153.6	-6.5
0x4	2	QPSK	128	1024	307.2	- 3.5
0x5	4	QPSK	128	2048	307.2	- 3.5
0x6	1	QPSK	64	1024	614.4	- 0.6
0x7	2	QPSK	64	2048	614.4	- 0.5
0x8	2	QPSK	64	3072	921.6	+ 2.2
0x9	1	QPSK	64	2048	1228.8	+ 3.9
0xa	2	16 QAM	64	4096	1228.8	+ 4.0
0xb	1	8PSK	64	3072	1843.3	+ 8.0
0xc	1	16QAM	64	4096	2457.6	+ 10.3
0xd	2	16QAM	64	5120	1536.0	In Rev A
0xe	1	16QAM	64	5120	3072.0	In Rev  A

If a place where sector overlap exists, the C/I will not be necessarily high if with high value of Rx. So C/I value in sector overlap area is low. Pilot pollution have greater effect on C/I value in EVDO network because an AT demodulates signals from only one sector at a time where as an MS can demodulate signals from three or more sectors in 1X network.

PER:

PER is similar to FER in 1X network .It affects the forward data rate as in C/I .It includes both Forward PER(EV_RX_PER) and Reverse PER  (EV_TX_PER).The high value of PER means the lower RLP throughput because of the repeated transmission in the RLP layer. In reverse link it is proportional to the C/I.

DRC Value:

It is related to C/I as shown in above table and PER. It depends up on the quality of air interface.

EV_RX_RLP_Throughput_Instant:  

                            

It is related to DRC value and number of active users.

Reverse Rate:

It is similar to CDMA 2001X data service.

Coverage Counter:

Forward: RXAGC, Total C/I

Reverse : Tx Power

Quality Counter:

Application Layer:

FTP Download

FTP Upload

RLP layer:

EV_RX_RLP_Thr

EV_TX_RLP_Thr

Physical Layer:

EV_Rx_packet_Thr

EV_Rx_Pkt_Thr_Instant

EV_TX_Pkt_Thr

QOS:

EV_Rx_PER

EV_Tx_PER