Motorola MC-802 User Manual

Installing Motorola MC-802 Wireless WallPlate

The MC-802 Wireless WallPlate is a new addition to the PowerBroadband product family. This
application note details specific topologies and best practices used for the installation of the
Wireless WallPlate. To set the proper context, we’ll start with a short introduction of the T3
PowerBroadband system. Key concepts used throughout the document are covered in Appendix
A. Best practice recommendations include a limited site survey procedure to determine
installation density.

T3 PowerBroadband System

The T3 system from Motorola is designed primarily for hospitality, but useful in any high density
MDU type installation. The T3 PowerBroadband Switch is installed in the central phone room of a
hotel or MDU, where it is cross connected onto the existing telephone wiring. The centrally
installed T3 PowerBroadband Switch has 25 ports for downstream CPEs, and 2 x GigE uplink
ports.

Two different types of remote CPEs are supported. The CPEs are installed in a hotel guest room
or any RJ11 jack within the MDU. The CPEs are designed as a wall plate form factor, and draw
operating power over the same telephone wire pair as broadband backhaul. Due to the form
factor, the name “WallPlate” is used to describe the CPE.

m2 WallPlate

The m2 WallPlate is a managed, Ethernet-only device. It has two 10/100Mb Ethernet
ports to connect access devices. 802.1Q VLANs and QoS can be managed throughout
the system, from the 25-port switch to each wall plate port.

MC-802 Wireless WallPlate

The Wireless WallPlate is just what it sounds like. It is a line-powered WallPlate with an
integrated 802.11b/g radio. The Wireless WallPlate has the same two 10/100Mb
Ethernet ports as the m2 WallPlate. All configuration, status and statistics for the
Wireless WallPlate are provided by the centrally installed T3 Switch.

Key features:

*600m is the limit of line power. If using an optional external power supply, T3 will deliver
broadband up to 1500m

The T3 system is comprised of the following components. In addition to the primary products
listed, filters are required for extra telephones that share the same wire pair.

• Line power up to 600 meters* for the m2 WallPlate, and 300 meters
for the MC-802 Wireless WallPlate. Line power is transparent to and
compatible with analog telephone service on the same wire

• One wire pair

• Optimized for IPTV and other advanced networking

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• Name: T3 PowerBroadband Switch, RoHS

• Motorola P/N: 558975-001-00

• Model: 45225

• Name: m2 Ethernet WallPlate, RoHS

• Motorola P/N: 549478-001-00

• Model: 45101

• Name: MC-802 Wireless WallPlate, RoHS

• Motorola P/N: 557925-001-00

• Model: 45010

T3 PowerBroadband Switch and m2/MC-802 WallPlates

TABLE OF CONTENTS

Installation Routine.............................................................................................3

Example Lite-Site Survey...................................................................................5

Example Installation...........................................................................................7

Example One: RoomLoss = 20dB.............................................................................................. 7

Example Two: RoomLoss = 15dB.............................................................................................. 8

Appendix A........................................................................................................10

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The goal of the installation can be stated relative to received signal strength (RSSI):

• -70dBm signal strength or better in every room

• Maximum of three co-channel cells within the carrier detect range

Perfect non-overlapping cell coverage is impossible to achieve. Read Appendix A for a
description of the carrier detect range and its effect on media access.

The network architect can control three variables when deciding where and how to install the
Wireless WallPlate network. Each variable has a different degree of effect on the overall network
performance.

• Physical placement is an important determinant of success. Because of the fast
installation routine, WallPlate placement is easy to adjust onsite during the installation.

• Channel assignment is used to create overlapping coverage cells and reduce the co-
channel cell overlaps. In most countries, channels 1 – 11 are availa ble; where only
channels 1, 6, 11 are non-overlapping for 802.11g modulation.

• Transmit power can be adjusted to fine-tune the signal strength and reduce some co-
channel interference. The WallPlates can be adjusted in 1dB increments from 14dBm to
1dBm. NOTE: Transmit power alone will not overcome an installation with too great a
density.

Full Site Survey

The goal of any wireless site survey covers two key purposes:

• Determine the number of APs required for adequate RSSI into each hotel guest room.

• Determine where and how to backhaul and power the AP installed in the hotel corridor.

Because the hotel guest is in the room, and not in the hallway, co-channel interference between
hallway-installed APs is usually not considered during a site survey. The focus is on pumping
enough power into the rooms to connect the hotel guest. When APs are installed in the hote l
corridor, mistakes are nearly impossible to correct. Adding an additional AP to cover a weak area
of the hotel is extremely difficult. Typical corrective action usually involves a higher gain antenna.
This is often ineffective if poor coverage is due to obstructions or multi-path reflections. Thus, an
extensive and expensive site survey is required.

Lite-Site Survey

With the Wireless WallPlate, the possible install locations include each room in the hotel.
Because of the fast installation, corrective action is very easy to execute if additional WallPlates
are required. Thus the site survey can be done quickly or not at all, with adjustments made
during the installation time.

Since the same construction material is used throughout the property, a complete room to room
site survey is unnecessary.

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The goal of the WallPlate site survey is to

determine the average RSSI loss through one

room/wall combination

Provisioning the WallPlates

• Order the number of WallPlates according to the RSSI loss through one room/wall. If the
floor material is the same as the walls e.g. concrete, then the vertical loss will be similar
(usually +3dB to +6dB). Offset the installation with each floor so that WallPlates are not
stacked vertically above one another.

• Order 5% extra WallPlates for coverage in non-standard areas of the hotel; such as
rooms blocked by an elevator shaft. During the installation, if coverage holes exist, plug
the hole by installing an extra WallPlate.

Once the typical RSSI loss through a hotel is determined, site surveys at similar hotels become
unnecessary as the same plan can be used repeatedly.

WallPlate Density Chart

Based on the RSSI loss from one room/wall, order the indicated number of WallPlates, plus 5%
margin.

RSSI loss is… Horizontal WP density Vertical WP offset

>30dB One every three rooms Install offset one room
>20dB and <30dB One every four rooms Install offset two rooms
>10dB and <20dB One every four to six rooms Install offset three rooms
<10dB One every eight rooms Install offset four rooms

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