LTE RAN – Long Term Evolution Radio Access Network

The LTE RAN consists of these parts:

§  RBS

§  OSS-RC RAN components

§  Interconnecting IP transport network

The following figure shows the logical structure of a single RBS in LTE RAN and how it interconnects with other components of LTE RAN:

Logically, each RBS is comprised of sectors, a digital unit, and a support system. Each sector is connected to one or a number of antenna unit groups. Connection to other RAN and core network elements is provided by the IP transport infrastructure. In some implementations, common elements of the RBS can be shared with other technologies such as WCDMA or GSM. Refer to RBS Configurations for further details.

The following list defines terms used to describe parts of the LTE RBS:
Antenna Unit Group		An Antenna Unit Group (AUG) is the logical structure that includes all details of an antenna and associated equipment. This includes the antenna, and any associated Tower Mounted Amplifiers (TMA) and Remote Electrical Tilt (RET) equipment. An AUG may contain a single branch as in the case of a vertically polarized antenna, or it may contain two branches in the case of a cross polar antenna. Each AUG is connected to one sector. Multi-band antennas may be logically connected to more than one AUG with the different frequency band elements of the antenna connect to different AUGs.
Cell		A part of a sector with its own carrier frequency and channels within the sector frequency band. There may be up to three cells per RBS. It is possible to configure only one cell per sector.
CPRI Connection		The Common Public Radio Interface (CPRI) connection provides the communications link between the digital unit and the radio unit. The CPRI standard allows the use of either electrical or optical interface cables. Electrical cables are used for radio units installed in the RBS cabinet and optical cables are used for remote radio units.
Digital Unit LTE		The Digital Unit LTE (DUL) includes the baseband, control, and switching functions of the LTE component of the RBS. It also contains the interfaces to the RUs, IP transport and RBS synchronization. The baseband capacity is pooled to support multiple sectors. Multiple digital units can be installed in an RBS. Refer to Digital Unit Description for further details.
eNode B		The terminology used in the 3GPP standards for an RBS.
IP Transport		The IP Transport provides connectivity from the RBS to the core network, to other RBSs, and to OSS-RC. System synchronization can also be provided via the IP transport interface using the Clock Source over NTP feature. The physical IP Transport infrastructure provides a number of logical channels. Refer to Transport Network Configuration for further details.
MME		The Mobility Management Entity (MME) manages the core network control functions. The MME nodes are designed to operate in a pooled architecture. The MME handles the mobility and session management functions including: UE registration and detachment handling Security and Authentication, Authorization and Accounting (AAA) Evolved Packet System (EPS) bearer handling Mobility Anchor for active-mode UE Mobility Management for idle-mode UE
OSS-RC		OSS-RC facilitates remote network management of LTE RAN.
Radio Unit		A Radio Unit (RU) refers to the physical hardware that serves a sector. Each radio unit is connected to antenna equipment that is part of an AUG. A radio unit can be physically located in the RBS cabinet, or it can be located externally to the RBS where it is referred to as a Remote Radio Unit (RRU). Refer to Radio Unit Description for further details.
Synchronization		The LTE Digital Unit uses an external synchronization source for generating the required system clock signals. The default method for synchronization is via external Global Positioning System (GPS) equipment. It is also possible to use a Network Time Protocol (NTP) time server to provide synchronization via the IP transport interface. For further details refer to Clock Source over NTP.
RET		Remote Electrical Tilt control signalling allows the antenna electrical tilt to be read or adjusted from a remote location such as from OSS-RC.
Sector		A geographical area spanned by the transmission angle from one or a group of antennas. The sector is configured to handle one specific frequency band.
SGW		The Serving Gateway (SGW) provides an interface to external networks for User Plane (UP) data. It is also anchor point for the user plane for UE mobility between RBS. The SGW also performs some Quality of Service (QoS) related signalling. The SGW nodes are designed to operate in a pooled architecture.
Support System		The Support System provides basic functions to the RBS. This can includes functions such as power supplies, battery backup, external alarms, and climate control systems. In some instances the Support System can be shared with other technologies. Refer to Support System for further details.
TMA		The Tower Mounted Amplifier (TMA) improves uplink system sensitivity and uplink coverage. TMAs are mounted close to the antenna and amplify the uplink Radio Frequency (RF) signals.

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.

WCDMA RAN ( Radio Access Network)

WCDMA RAN

WCDMA RAN is a part of the 3rd generation (3G) mobile system, and comprises:

• OSS-RC
• RNC
• RANAG
• RBS

WCDMA RAN has interfaces towards the Core Network (CN), and towards the external Network Management Systems (NMS).

WCDMA RAN provides Radio Access Bearers (RAB) between the CN and the subscriber's User Equipment (UE) for speech, data, and multimedia services.

The Network Elements (NEs) RNC, RANAG, and RBS provide and manage the data links between WCDMA RAN and the UE. The links between the NEs in WCDMA RAN carry the user data within WCDMA RAN. These physical links are also used to carry O&M data. See figure for an overview of WCDMA RAN. 

Ericsson Counter : Dropped Calls

TFNDROP : The total number of dropped full-rate TCH in underlaid subcell. The counter is also available for half-rate and for overlaid subcells, e.g. THNDROPSUB.

TFNCEDROP : The total number of dropped full rate TCH connections in underlaid subcell that occur when a subscriber to subscriber connection has already been established. The establishment of subscriber to subscriber connection is assured if the connection is dropped between the DTAP messages CONNECT ACKNOWLEDGE and RELEASE or DISCONNECT (whichever of RELEASE or DISCONNECT comes first).

TFDISTA : Total number of dropped full-rate TCH connections at excessive TA. Also available for half-rate, e.g. THDISTA.

TFDISSSUL : Total number of dropped full-rate TCH connection at low signal strength on uplink in underlaid subcell i.e. below LOWSSUL. Different combinations for overlaid subcell, up/down and both-way link and half-rate, e.g. THDISSSBLSUBis the signal strength drop counter for half-rate, both links in overlaid subcell. If both links have low signal strength, only the both link counters are stepped.

TFDISFERUL :  Total number of dropped full-rate TCH connections at high FER on uplink in underlaid subcell i.e. worse than (above) HIGHFERULFR. Different combinations for overlaid subcell, up/down and both-way link and codec, e.g. THDISFERBLSUB is the bad quality drop counter for half-rate, both links in overlaid subcell. If both links have bad quality, only the both link counters are stepped.

TFDISQAUL : Total number of dropped TCH connection due to bad quality based on RXQUAL on uplink in underlaid subcell i.e. worse than (above) BADQUL. Different combinations for overlaid subcell, up/down and bothway link and half-rate, e.g. THDISQABLSUBis the bad quality drop counter for half-rate, both links in overlaid subcell. If both links have bad quality, only the both link counters are stepped.

TFSUDLOS : Sudden loss of connection in underlaid subcell. Sudden loss apply when the locating algorithm indicates missing measurement results, but none of the urgency conditions mentioned above (that is excessive TA, low signal strength, high FER or bad quality) apply. The counter is also available for half-rate and for overlaid subcells, e.g. THSUDLOSSUB.

T_DR_BQ : The rate of TCH drops at bad quality on either uplink, downlink or both for the whole cell.

T_DR_FER : The rate of TCH drops at high FER on either uplink, downlink or both for the whole cell.

T_DR_TA :  The rate of TCH drops due to excessive Timing Advance for the whole cell.

T_DR_SUD : The rate of TCH drops due to sudden loss of the connection for the whole cell.

T_DR_OTH :  The rate of TCH drops due to other reasons than the above known reasons.

TFDISTAA : Total number of dropped AMR full-rate TCH connections at excessive TA. Also available for half-rate, e.g. THDISTAA .

TFDISSULA : Total number of dropped AMR full-rate TCH connections due to low signal strength on uplink in underlaid subcell i.e. below LOWSSUL. Different combinations for overlaid subcell, up/down/both links and half-rate, e.g. THDISSBLSUBAis the signal strength drop counter for AMR half-rate, both links in overlaid subcell. If both links have low signal strength, only the both link counters are stepped.

TFDISFERULA : Total number of dropped AMR full rate TCH connections at high FER on uplink in underlaid subcell. Different combinations for overlaid subcell, up/down and both-way link and codec, e.g. THDISFERBLSUBA is the bad quality drop counter for AMR half-rate, both links in overlaid subcell. If both links have bad quality, only the both link counters are stepped.

TFDISQAULA : Total number of dropped AMR full-rate TCH connections at bad quality on uplink in underlaid subcell. Different combinations for overlaid subcell, up/down/both links and half-rate, e.g. THDISQABLSUBAis the bad quality drop counter for AMR half-rate, both links in overlaid subcell. If both links have bad quality, only the both link counters are stepped.

TFSUDLOSA : Sudden loss of AMR full-rate connection in underlaid subcell. Sudden loss apply when the locating algorithm indicates missing measurement results, but none of the urgency conditions mentioned above (that is excessive TA, low signal strength, high FER or bad quality) apply. The counter is also available for AMR half-rate and for overlaid subcells, e.g. THSUDLOSSUBA.

Read Also other topis : Ericsson Counter: Call Attempts, Drops on SDCCH, Congestion, Paging, Handover, Speech Quality, Intra-Cell Handover, OL/UL Subcell

Ericsson Counter : Dropped Calls

TFNDROP : The total number of dropped full-rate TCH in underlaid subcell. The counter is also available for half-rate and for overlaid subcells, e.g. THNDROPSUB.

TFNCEDROP : The total number of dropped full rate TCH connections in underlaid subcell that occur when a subscriber to subscriber connection has already been established. The establishment of subscriber to subscriber connection is assured if the connection is dropped between the DTAP messages CONNECT ACKNOWLEDGE and RELEASE or DISCONNECT (whichever of RELEASE or DISCONNECT comes first).

TFDISTA : Total number of dropped full-rate TCH connections at excessive TA. Also available for half-rate, e.g. THDISTA.

TFDISSSUL : Total number of dropped full-rate TCH connection at low signal strength on uplink in underlaid subcell i.e. below LOWSSUL. Different combinations for overlaid subcell, up/down and both-way link and half-rate, e.g. THDISSSBLSUBis the signal strength drop counter for half-rate, both links in overlaid subcell. If both links have low signal strength, only the both link counters are stepped.

TFDISFERUL :  Total number of dropped full-rate TCH connections at high FER on uplink in underlaid subcell i.e. worse than (above) HIGHFERULFR. Different combinations for overlaid subcell, up/down and both-way link and codec, e.g. THDISFERBLSUB is the bad quality drop counter for half-rate, both links in overlaid subcell. If both links have bad quality, only the both link counters are stepped.

TFDISQAUL : Total number of dropped TCH connection due to bad quality based on RXQUAL on uplink in underlaid subcell i.e. worse than (above) BADQUL. Different combinations for overlaid subcell, up/down and bothway link and half-rate, e.g. THDISQABLSUBis the bad quality drop counter for half-rate, both links in overlaid subcell. If both links have bad quality, only the both link counters are stepped.

TFSUDLOS : Sudden loss of connection in underlaid subcell. Sudden loss apply when the locating algorithm indicates missing measurement results, but none of the urgency conditions mentioned above (that is excessive TA, low signal strength, high FER or bad quality) apply. The counter is also available for half-rate and for overlaid subcells, e.g. THSUDLOSSUB.

T_DR_BQ : The rate of TCH drops at bad quality on either uplink, downlink or both for the whole cell.

T_DR_FER : The rate of TCH drops at high FER on either uplink, downlink or both for the whole cell.

T_DR_TA :  The rate of TCH drops due to excessive Timing Advance for the whole cell.

T_DR_SUD : The rate of TCH drops due to sudden loss of the connection for the whole cell.

T_DR_OTH :  The rate of TCH drops due to other reasons than the above known reasons.

TFDISTAA : Total number of dropped AMR full-rate TCH connections at excessive TA. Also available for half-rate, e.g. THDISTAA .

TFDISSULA : Total number of dropped AMR full-rate TCH connections due to low signal strength on uplink in underlaid subcell i.e. below LOWSSUL. Different combinations for overlaid subcell, up/down/both links and half-rate, e.g. THDISSBLSUBAis the signal strength drop counter for AMR half-rate, both links in overlaid subcell. If both links have low signal strength, only the both link counters are stepped.

TFDISFERULA : Total number of dropped AMR full rate TCH connections at high FER on uplink in underlaid subcell. Different combinations for overlaid subcell, up/down and both-way link and codec, e.g. THDISFERBLSUBA is the bad quality drop counter for AMR half-rate, both links in overlaid subcell. If both links have bad quality, only the both link counters are stepped.

TFDISQAULA : Total number of dropped AMR full-rate TCH connections at bad quality on uplink in underlaid subcell. Different combinations for overlaid subcell, up/down/both links and half-rate, e.g. THDISQABLSUBAis the bad quality drop counter for AMR half-rate, both links in overlaid subcell. If both links have bad quality, only the both link counters are stepped.

TFSUDLOSA : Sudden loss of AMR full-rate connection in underlaid subcell. Sudden loss apply when the locating algorithm indicates missing measurement results, but none of the urgency conditions mentioned above (that is excessive TA, low signal strength, high FER or bad quality) apply. The counter is also available for AMR half-rate and for overlaid subcells, e.g. THSUDLOSSUBA.

Read Also other topis : Ericsson Counter: Call Attempts, Drops on SDCCH, Congestion, Paging, Handover, Speech Quality, Intra-Cell Handover, OL/UL Subcell

Ericsson Counter: Handover

HOVERCNT : Number of Handover Commands sent to the MS.

HOVERSUC : Number of successful handover to the neighbouring cell.

HORTTOCH : Number of handovers that result in a return to the old channel after a failure of a handover attempt to a neighbouring cell.

HODUPFT : Number of successful handovers back to old cell within 10 seconds.

HOTOKCL : Handover attempt made to better K-cell (only for the Ericsson 1 locating algorithm). The corresponding for better L-cell is called HOTOLCL.

HOTOHCS :  Handover attempt due to HCS.

HODWNQA : Number of handover attempts due to bad downlink quality. There is one HO counter for bad uplink quality called HOUPLQAand one for excessive timing advance called HOEXCTA.

HOASBCL : Number of assignment attempts to better cell. The corresponding counter for assignment to worse cell is called HOASWCL.

HOSUCBCL : Number of successful assignment attempts to better cell. The corresponding counter for assignment to worse cell is called HOSUCWCL.

HOATTLSS : Number of handover attempts when the serving cell is a low signal strength cell. The corresponding counter for attempts at high signal strength is called HOATTHSS.

HOATTHR :  Number of handover attempts at high handover rate. The counter for successful handovers at high handover rate is HOSUCHR.

Read Also other topis : Ericsson Counter: Call Attempts, Drops on SDCCH, Congestion, Dropped Calls, Paging, Speech Quality, Intra-Cell Handover, OL/UL Subcell

Ericsson Counter : Dynamic Overlaid/Underlaid Subcell

HOAATOL Number of handover attempts from underlaid to overlaid subcell. The corresponding counter for handover tounderlaid subcell is called HOAATUL.

HOSUCOL Number of successful assignment attempts to overlaid subcell. The corresponding counter for underlaid subcell is called HOSUCUL.

HOATTULMAXIHO Number of handover attempts from OL to UL subcell due to maximum number of intracell handovers in OL subcell.

HOSUCULMAXIHO Number of successful handover attempts from OL to UL subcell due to maximum number of intracell handovers in OL subcell.

HOATTOLMAXIHO Number of handover attempts from UL to OL subcell due to maximum number of intracell handovers in UL subcell.

HOSUCOLMAXIHO Number of successful handover attempts from UL to OL subcell due to maximum number of intracell handovers in UL subcell.

LOLCOMUL Subcell change attempts from OL to UL when reaching LOL criteria for subcell change.

LOLSUCUL Successful subcell changes from OL to UL when the LOL criterion was the reason for the subcell change.

DTCBCOMUL Subcell change attempts from OL to UL when reaching DTCB criteria for subcell change.

DTCBSUCUL Successful subcell changes from OL to UL when the  DTCB criterion was the reason for the subcell change.

TAOLCOMUL Subcell change attempts from OL to UL when reaching TAOL criteria for subcell change.

TAOLSUCUL Successful subcell changes from OL to UL when the TAOL criterion was the reason for the subcell change.

SCLDCOMUL Subcell change attempts from OL to UL due to dynamic OL/UL subcell load distribution.

SCLDSUCUL Successful subcell changes from OL to UL when subcell load distribution (SCLD) was the reason for change.

OLSCLDCOM Subcell change attempts from UL to OL when subcell load distribution (SCLD) was the reason for change.

OLSCLDSUC Successful subcell changes from UL to OL when subcell load distribution (SCLD) was the reason for change

Read Also other topis : Ericsson Counter: Call Attempts, Drops on SDCCH, Congestion, Dropped Calls, Handover, Speech Quality, Intra-Cell Handover, Paging