The document provides an overview and comparison of the Mobile Location Center (MLC) and Wireless Location System (WLS) platforms. Both platforms provide network-based location services for 911 calls, using technologies like TA/NMR, A-GPS, and U-TDOA to determine a caller's location. While they perform the same functions, the MLC is more command-line focused while the WLS includes more graphical user interfaces. The document then describes the key components and capabilities of each platform in more detail.

1. Comparison & overview of MLC - Andrew Corporation & WLS –
Trueposition platforms I supported for the past 12 years which
both have been discontinued as of 2015 (including companies)
and the responsibilities have been transferred to Intrado and TCS
(E911 service providers) for network base 911 services.
Mobile Location Center and Wireless Location System – both products
provide the same service; however, with a few internal naming differences
in reference to overall platform including hardware & software they both
perform the same service. A note: Andrew Corp a subsidiary of
CommScope actually manufactured the LMU (location measurement unit)
hardware which Andrew Corp has. Andrew Corp named their
measurement unit WLS (wireless location system). Also, they both run on
Unix, use MySQL, and another RDBMS. MLC is more command-line.
Whereas, WLS is more command line for engineering and provisioning,
but it has a GUI for network operations, analytics, performance analysis,
auto-provisioning and system admin (user/group administration).
Basically more user friendly.

2. We will start with Andrew Corporation
The Mobile Location Center is a high-availability, scalable central office
platform for determining the physical location of a handset in a cellular
telephone network.
Note: The generic terminology used for “handset” varies with the
context: in a GSM network, the term “mobile station (MS)” is used; in a
UMTS network, “user equipment (UE)” is used.

3. The Mobile Location Center provides the
following network nodes:
• Gateway Mobile Location Center (GMLC)
• Serving Mobile Location Center (SMLC)
• Standalone Assisted-GPS SMLC (SAS)
The Mobile Location Center provides the following configurations:
• *GMLC-only
• SMLC-only on the GEN3 platform
• SAS-only on the GEN3 platform
• *GMLC-SMLC combination
• *GMLC-SAS combination

4. The Mobile Location Center is open-standards-compliant; it complies
with the following open standards: location (ETSI/3GPP), emergency
services (for North America), wireless (ETSI/3GPP), SS7 (ITU and ANSI),
CORBA, SNMP, internet (HTTP, HTTPS and XML). The Mobile Location
Center uses either the Ulticom Signalware SS7 interface (on GEN3 MLC
platforms) or the Nortel Universal Signaling Point (on pre-GEN3
platforms) to communicate with the SS7 network.

5. The Mobile Location Center supports:
• GSM networking protocols
• UMTS networking protocols
• location services (LCS) messaging
• MTP3 (standard SS7) and M3UA (SIGTRAN) signaling
• North American emergency services
• Mobile Location Protocol (MLP)
• GMLC geographic redundancy

6. • TA/NMR location technology, which uses Timing Advance (TA) and
• Network Measurement Report (NMR) information to determine the
• location of a handset
• Assisted-GPS (A-GPS) location technology, which uses GPS assistance
• data downloaded from a third-party Wide Area Reference Network
• (WARN) to help determine the location of GPS-capable handsets
• The Mobile Location Center supports:
1. both network-assisted and autonomous handset-based A-GPS, where the
position computation occurs in the handset
2. handset-assisted A-GPS, where the handset provides satellite
measurements and the position computation occurs in the network (inthe
MLC)
3. conventional GPS, where the position computation occurs in the handset
without assistance data

7. • Uplink Time Difference of Arrival (U-TDOA) location technology, which allows the
use of external U-TDOA Location Servers to determine the location of handsets.
The Mobile Location Center provides:
A Gateway Mobile Location Center (GMLC) network node, which incorporates
standards-based as well as pre-standards–based support for location requests using
cell-based location technology
A Serving Mobile Location Center (SMLC) network node, which incorporates the
following position determining entities (PDE):
• TA/NMR
• A-GPS
• U-TDOA
• cell-based
Note: The SMLC can optionally be set up to forward selected location requests to
remote SMLCs for position determination.

8. A Stand-alone A-GPS SMLC (SAS) UMTS network node, which provides a GPS
assistance data server that supports both implicit and explicit data requests
The SAS-to-RNC (Iupc) interface can support one or both of:
• standards-based SIGTRAN over SCTP associations
• TCP Adaption Layer (TAL) over direct TCP/IP connections
• an optional location-based application: the Mobile Locator
• an application interface for Mobile Location Protocol (MLP) compliant LCS
clients (location-based applications)
• support for the Lc interface which enables a Service Control Function (SCF)
to request handset location information from the GMLC
• an emergency services application interface (ESAI) for Emergency Services
support
• secure, open interfaces for operations, administration, maintenance (OAM)
and provisioning

9. • an optional operations support system (OSS) server which can be
used for:
1. off-board storage of key MLC operations and performance data required by
an operator—including storage of logs, event records, configurations and
key performance indicator (KPI) data.
2. running OSS tools such as the MLC KPI reporting tool which is available for
analysis of MLC data in standard reports.
Note: The KPI reporting tool can also be run on compliant operator
provided equipment.
• a standards-based application interface for Mobile Location Protocol
applications
• Lc interface support

10. • TA/NMR location technology
• A-GPS location technology
1. MS-based and MS-assisted for SMLC
2. UE-based and UE-assisted for SAS
3. SET-based and SET-assisted for SLP
• U-TDOA location technology
• Lb tandem support, where the SMLC forwards selected location requests
(received on the Lb interface from BSCs) to remote SMLCs for position
determination
• North American Emergency Services support the Mobile Locator
application
• GMLC geographic redundancy
• enhanced network topography security through the cell hiding feature
which allows the random variation of the location returned from cell-based
positioning methods

11. Network architecture
• GSM logical architecture: The GSM logical architecture for delivering
position information to location services.

12. UMTS logical architecture: The UMTS logical architecture is an
evolution of the GSM architecture for LCS.
1. The interface to the GMLC remains the same.
2. The SMLC is incorporated into the Radio Network Controller (RNC)
functionality.

13. The functional components of the Mobile
Location Center GMLC, SMLC and SAS

16. Now for Trueposition
Overview of the TruePosition Finder Wireless Location System (WLS). It
includes descriptions of the main elements of the system:
• Anyphone™ Location Measurement Unit (LMU)
• iFind™ Serving Mobile Location Center (SMLC)
• ServiceGate™ Wireless Location Gateway (WLG)
• Abis Monitoring System (AMS)
• Element Management System (EMS)
• SCOUT™ application
• Angle of Arrival (AOA)
The Overview is a summary of the principles of operation explaining how the
WLS functions as a whole.

17. EMS
The EMS is the primary operator interface for the TruePosition WLS.
The EMS enables the TruePosition WLS operators to perform network
management, limited system configuration management, alarm
management, and fault isolation. It consists of one server and multiple
clients, and connects to each WLS using the OSS Gateway. EMS clients,
which serve as EMS operator consoles, provide varied levels of access
to all elements within the network.

18. SCOUT application
TruePosition’s SCOUT application suite refers to an integrated set of
capabilities used to manage, design, configure, predict the accuracy of,
and perform analysis and testing of a WLS. As a component of the WLS,
The SCOUT application interfaces with the LG, the OSS Gateway, the
iFind SMLC, and Drive Test client, providing options for importing cell
site data, synchronizing configuration data with operating systems, and
generating reports detailing configurations

19. LMU
The Anyphone LMU is the primary TruePosition equipment deployed
at a carrier's cell site. It tunes to directed frequencies, gathers data, and
forwards the data to the SMLC.
SMLC
The iFind SMLC digital signal- processing unit is typically located at the
carrier's switching location, but it can be remotely distributed to any
location. The primary functions are:
• Receiving reports on signal detection from the LMUs
• Performing location processing
• Calculating the location estimate for each signal
• Communicating with the WLG regarding location records

20. WLG
The ServiceGate WLG manages the TruePosition network and provides
carrier access to location records; it is responsible for the collection and
distribution of location records. It also maintains configuration
information and supports network management. A ServiceGate WLG
may be located in any centralized facility, such as a network operations
center, switching facility, or other secure facility.
MG
The Master Gateway manages the software elements of the WLG. The
state of the WLG is coordinated and presented by the master gateway.

21. LG
The Location Gateway application is responsible for distributing
locations to requesting applications. It also generates billing metrics for
locations distributed to each application. The LG application runs on
the ServiceGate WLG server.
SG
The Signaling Gateway connects to a base station controller and
receives location requests. It sends the location requests to the LG,
which in turn begins location processing.

22. OSS Gateway
The OSS Gateway application provides Operation Support Subsystem
functions for the TruePosition WLS. The ServiceGate WLG server hosts
the OSS Gateway and the LG applications. The OSS Gateway aids in WLS
provisioning from the SCOUT component and performs alarm
correlation for faults generated within the WLS. The OSS Gateway
enables the interface with the TruePosition EMS using a Simple
Network Management Protocol (SNMP) for fault, performance, and
limited configuration management. It generates billing metrics for
locations distributed to each application and provides an external
interface to support external management tools such as NetExpert. The
SG application runs on the ServiceGate WLG server.

23. Routers and Switches
Routers and switches work together to manage information traffic
within the WLS. They allow the different components of the WLS to
communicate. The router uses a Wide Area Network (WAN) connection
between WLS equipment components and sites. The switches provide
Ethernet switching.
SMLC MUX
The SMLC multiplexor (MUX) multiplexes T1/E1 connections from
LMUs to T3/E3 connections to the SMLC cluster, and supports SMLC
failover for redundancy. This provides carrierclass availability for this
system.

24. AMS, AMS MUX, AMS Router and Switch
The Abis Monitoring System continuously monitors all Abis signaling
links in a GSM network to which the AMS is connected. The AMS
captures messages in the GSM call setup procedure for mobiles and
forwards the data contained in those messages to the LG for
subsequent processing.
The AMS MUX combines multiple inputs into an aggregate signal to be
transported via a single transmission channel. It is used to transport the
messages from the network to the AMS.
The AMS router and switch manages information traffic within the
AMS network and supports communication between the AMS servers,
the WLS, and remote AMSs.