Author : Ray Khastur : http://www.linkedin.com/pub/ray-khastur/36/965/b7a

4G LTE Drive Test Introduction

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 2

Drive Test Peripheral

Notebook

GPS

LTE Dongle

LTE Radio Parameter

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 4

LTE Main Radio Parameter

PCI (0~503) RSRP (- 130 ~ -50) dBm

SINR (-20 ~ 30) dB MIMO (TM1, TM2, TM3, TM7)

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 5

UE State Information

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 6

Throughput Measurement

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 7

DL RB Used on High Speed Throughput

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 8

DL RB Used on Low Speed Throughput

LTE Access

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 10

Attach Request Procedure – Event List

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 11

Attach Request Procedure – L3 Message

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 12

UE Attach Procedure RACH

RRC Setup

Authentication

E-RAB

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 13

Access Failure Reasons Random access fail reasons: • Bad RF conditions ( SINR<-3 or RSRP<-120) • UE configuration parameter (Monitor the

top-1 fail UE for analysis) • Enode-B configuration parameter (Parameter

checking at the TOP-1 fail site) • Core-network configuration parameter (If all

the site in one CN often fail)

RRC Setup Fail reasons: • Case-1: often fail by One UE: trace the UE and get

the RF signal performance. Maybe cause by the UE signal or UE configuration setting.

• Case-2: Often fail in one site by different UEs: Trouble shooting the problem site.

Authentication will happen between UE and MME, EnodeB just transfer the information. So we have to check the “S1 interface message” in core-M2000.

Authentication fail in three reasons: • UE did not feedback all the information (4 messages). -----check the UE signal

conditions. • Core-Network no reply “Initial UE context setup Req)-----UE and CN need to be

check. • Core-Network release “S1 UE Context Rel_CMD”-----UE and CN need to be check.

ERAB fail Reason: •Security mode negotiation problem (“RRC SEQUR Mode Fail” reply by UE)----UE problem •Security mode negotiation problem (No receive “RRC SECUR MODE CMP” from UE”----UE RF conditions. •UE CAP enquiry fail.(No receive “RRC_UE_CAP_RSP”from UE”----UE RF conditions. •RECFM not complete (No receive” RRC CONN RECFG CMP” from UE)----UE RF conditions.

LTE Neighboring Cell

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 15

Serving and Neighboring Cell Meas_RPRT

S1AP_Handover_Required

S1AP_Handover_CMDRRC_CONN_RECFG

(HO_CMD) S1AP_eNB_Status_Transfer

UE S_eNB T_eNB Core Network

S1AP_Handover_NotifyS1AP_UE_CONTEXT_REL_CMD

RRC_CONN_RECFG_CMP(HO_CMP)

RRC_CONN_RECFGRRC_CONN_RECFG_CMP

UU_interface X2_interface S1_interface

S1AP_Handover_REQ_ACK

S1AP_MME_Status_Transfer

S1AP_UE_CONTEXT_REL_CMP

S1AP_Handover_Request

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 16

ANR vs UE capability : Inter-eNodeB 1. The source eNodeB delivers the intra-frequency measurement

configuration to the UE, instructing the UE to measure neighboring cells that work on the frequencies specified in the measurement configuration.

2. The UE detects that the PCI of cell B meets the measurement requirements, and reports the PCI to the source eNodeB.

3. The source eNodeB checks whether its intra-RAT NCL includes the PCI of cell B. If so, the procedure ends. If not, the source eNodeB sends the measurement configuration to the UE, instructing the UE to read the ECGI, tracking area code (TAC), and PLMN ID list of cell B.

4. The source eNodeB allows the UE to read these parameters over the broadcast channel (BCH).

5. The UE reports the obtained parameter values to the source eNodeB.

Notes: ANR features of an UE will effect the capability of the UE to read the ECGI, TAC and other information of the target cell. Thus, failure to do so the target cell information can’t be read.

4G LTE Drive Test Introduction @ Floatway Learning Centre , slide number 17

Due to the source cell and target cell are located under the same BBU board, thus target cell information can be search and obtain internally referring to the PCI. Therefore although UE doesn’t support ANR features, it doesn’t affect the reading of ECGI, TAC and other information of the target cell which required for the creation of NCL.

1. The source eNodeB delivers the intra-frequency measurement configuration to the UE, instructing the UE to measure neighboring cells that work on the frequencies specified in the measurement configuration.

2. The UE detects that the PCI of target cell (Cell A) meets the measurement requirements, and reports the PCI to the source cell (Cell B).

ANR vs UE capability : Intra-eNodeB