PRACH Power

-

Initial PRACH (The first PRACH that UE transmit) is determined by the following formula.

Initial RACH Preamble Power = Primary CPICH TX Power – CPICH_RSCP + UL_Interference + Constant Value

CPICH_RSCP is the power directly measured by UE and all other parameters are calculated (obtained) from system information. The related parameter and system information is as follows.

System Information
Information Element
Example Value
SIB3
Maximum Allowed UL Tx Power
21 dBm
SIB5
Primary CPICH Power
-8 dBm
Power Ramp Step
3 dB
Mmax
2
NB01min
10
NB02max
10
SIB7
UL Interference
-92

If UE fail to get AICH for the PRACH, it increment the PRACH power by Power Ramp Step (SIB5) and transmit the PRACH again. UE repeat this process until it gets AICH or it retried the specific number specified in SIB5.
Following screenshot is an example of PRACH transmission and retransmission. This is from a test resultl of 34.121 8.4.2.1. In this test case, Network intentionally does not send AICH so that UE keep sending PRACH with specified power increment in the specified number of times.


Popular posts from this blog

SCFT - Single Cell Function test

-
Single Cell Function test SCFT is for verifying whether individual BTS works well or not, by making a single cell function test of BTS hardware and software. Essential items to be tested are as follows: 1) BTS Transmitter Output Measurement Test 2) Initial parameter establishment (Pilot PN/System ID/Site ID/Frequency, Neighbor List) 3) Call Origination and Termination Test 4) Softer Handoff Test/Antenna installation check (Direction, Tilt, Transmission Line) 5) Single Cell Coverage Test 6) Noise Floor Test 7) Parameter check.
Read more

Troubleshooting for GSM KPIs (SD Block & SD Drop)

-
KPIs to be monitored: ·             SD Blocking ·             SD Drop SDCCH Channel: ·    SDCCH channel is a dedicated channel which is using for LAC updation, Call Setup, SMS in Ideal mode. It works in UL & DL SD Blocking: ·    SD Blocking means that you are not getting SD resource for the call origination. When MS connects with Network then RACH and AGCH are provided. After AGCH, SDCCH is provided but if SDCCH is not provided at this time due to some problem or due to unavailable of SD by BSC. KPI Formula in Ericsson: ·             SDCCH CONGESTION = (CCONGS / CCALLS) * 100 ·             CCONGS - Congestion counter. ·  ...
Read more

PS core network

-
Image
The PS core network consists of two parts, the traditional General Packet Radio Service (GPRS) core network and the new Evolved Packet System (EPS) core network. The PS core network connects mobile subscribers to Packet Data Networks (PDNs) such as the Internet, corporate networks or operator services networks.  a functional overview of the PS core network. Logical entities and interfaces are shown in black and form a 2G/3G network, while the blue boxes and lines in Figure  show the LTE/EPC related parts. The LTE/EPC network can be regarded as an extension and evolution of existing 2G/3G networks. From a node implementation perspective, there is no strict border between the two networks. The corresponding logical entities of GPRS and EPS networks can be deployed concurrently in Ericsson PS core nodes, such as the SGSN-MME and EPG; these are marked in red. In addition, Ericsson GPRS nodes can be upgraded with EPC functionality by software only. Network evolution i...
Read more