Chapter 2 System Description This Chapter describes the following: • System Overview, page 12 • Hub – Remote Comparison, page 13 • System Connections, page 15 • Hub Indoor Unit (IDU), page 17 • Hub Outdoor Unit (ODU), page 23 • Remote Indoor Unit (IDU), page 26 • Remote Outdoor Unit (ODU), page 30 Wavtrace™ PTM 1000 Operations and Maintenance Manual
12 Draft: 8/13 PTM 1000 Operations and Maintenance Manual System Overview The PTM 1000 broadband wireless system consists of two primary elements: a hub (indoor unit and outdoor unit) and multiple remotes (indoor and outdoor units), as shown in Figure 2. Figure 2 PTM 1000 Broadband Wireless System The hub is equivalent to a base station in cellular terminology. The hub is composed of an indoor unit (IDU) and an outdoor unit (ODU).
Chapter 2: System Description Draft: 8/13 13 The remote ODU is placed on top of the office building or other external structure, up to 1000 feet. The remote ODU can also be placed indoors. The remote ODU consists of a single parabolic antenna, its associated interface electronics and mounting frame. Hub – Remote Comparison The remote IDU is similar to the hub IDU. The following paragraphs compare their capabilities: • The remote is a single antenna/single airlink device.
14 Draft: 8/13 PTM 1000 Operations and Maintenance Manual • The PTM 1000 System requires "line of sight" between the hub antenna and remote antenna. For indoor mounting, the remote TRA must be placed near a window that maintains a line of sight to the hub. • Because the remote uses only one TRA for each remote IDU, the remote requires only one modem control function. Further, there is no need to frequency multiplex multiple IF signals onto the coaxial cable (there are no multiple IFs to multiplex).
Chapter 2: System Description Draft: 8/13 15 System Connections Hub Connections One hub IDU can support up to four outdoor frames (ODFs), with each ODF servicing a 90-degree quadrant. A pair of RG-8 coaxial cables run between the intermediate frequency distribution (IFD) printed circuit assemblies (PCAs) in the hub IDU and the outdoor distribution box (ODB) in the hub ODU, connecting the hub indoor unit to the outdoor unit. The two RG-8 coaxial cables provide an interface between the hub IDU and ODU.
16 Draft: 8/13 PTM 1000 Operations and Maintenance Manual Remote Connection The remote network connection uses much less bandwidth than the hub’s OC3 interface. The remote may have a maximum of 11 DS1 ports at this time. The hub is the distribution point and there are multiple remotes for each hub, but traffic flow is referenced to the remote. The PTM 1000 System references the forward link as the RF path from the Service Provider’s network connection through the hub to the remote.
Chapter 2: System Description Draft: 8/13 17 Hub Indoor Unit (IDU) Fan Assembly Plenum Modem Control Assembly (MCA) 10Base-T (Beta only; not for production) Power Supply Interface (PSI) I/F Combine and Power Distribution (IFD) IDU Management Processor (IMP) Network Interface (NET) Power Distribution Plenum Figure 3 hub Indoor Unit (IDU) Note The hub IDU is shipped with printed circuit assemblies (PCAs) installed. The PCAs are tested as a customer-configured system.
18 Draft: 8/13 PTM 1000 Operations and Maintenance Manual • Indoor management processor (IMP) • Power supply interface (PSI) • Network interface (NET) The common control shelf contains up to eight modem control assemblies (MCAs) and two IFD PCAs. The MCA and IFD PCAs service a group of transmitter-receiver assemblies (TRAs) on a common ODF. The MCA and IFD PCAs combine to form two MCA groups.
Chapter 2: System Description Draft: 8/13 19 Indoor Management Processor (IMP) The IMP PCA provides primary management of the PTM system, including the hub (IDU, ODU) and the remote (IDU, ODU). The IMP PCA maintains configuration and alarm information for the entire system. Note Software upgrades are downloaded to the IMP PCA. The IMP PCA performs the following functions: • It provides the interface to OAM and P management and craft maintenance workstations.
20 Draft: 8/13 PTM 1000 Operations and Maintenance Manual Network Interface (NET) The NET PCA provides: • Interface between the airlink and the SONET communication network • Pathway for remote-to-remote switching The OC-3 NET module is the interface between the OC-3 SONET optical input/outputs and the switching matrix on the NET PCA. The module is a self-contained OC-3 interface. Note The plug-in module used on the PCA is not hot-swappable.
Chapter 2: System Description Draft: 8/13 21 Modem Control Assembly (MCA) The MCA performs time division duplex (TDD) and time division multiple access (TDMA) acquisition and control of intermediate frequency (I/F) carriers, which form the wireless airlink. A hub IDU supports up to eight MCAs. The MCA performs the modulation of the digital baseband signal to and from an intermediate frequency (I/F) using a quadrature amplitude modulated (QAM) method.
22 Draft: 8/13 PTM 1000 Operations and Maintenance Manual Power Distribution Plenum The PTM 1000 requires customer supplied –48Vdc power capable of delivering that voltage at 10A per shelf. A connector in the back of the Power Distribution Plenum receives power from the power supply and distributes it throughout the system. All power circuits into the system have 10A fuses and an LED for each fuse per fan assembly. A green LED indicates that there is power to the Power Distribution Plenum.
Chapter 2: System Description Draft: 8/13 23 Hub Outdoor Unit (ODU) Figure 4 hub Outdoor Unit (ODU) The hub ODU comprises multiple horn antennas with their associated interface electronics and mounting frames (see Figure 4). Two tiers of TRAs consisting of up to three antennas per tier can be mounted on an outdoor frame (ODF). Typically, four ODFs are used to service a 360-degree area surrounding a building.
24 Draft: 8/13 PTM 1000 Operations and Maintenance Manual Transmitter-Receiver Assembly (TRA) Figure 5 Transmitter-Receiver Assembly (TRA) Each antenna uses interface electronics provided by the transmitter PCA. The term "transmitter-receiver assembly" refers to the antenna, the transmitter PCA, the millimeter-wave front end, and the mechanical housing. The TRA forms a single digital interface, providing all of the processing of the RF signals to and from the antenna.
Chapter 2: System Description Draft: 8/13 25 The ODB manages the frequency multiplexing of reverse and forward IF signals between the IDU and ODU. There is one reverse cable and one forward cable for each ODB. Each cable carries signals for four point-to-multipoint TRAs and a coax control channel.
26 Draft: 8/13 PTM 1000 Operations and Maintenance Manual Remote Indoor Unit (IDU) Note The remote IDU is shipped with individual printed circuit assemblies (PCAs) installed. The PCAs are tested as a customer-configured system.
Chapter 2: System Description Draft: 8/13 27 The remote IDU uses forced air cooling and has air slots on both sides of the enclosures. The remote MCA and motherboard PCAs are powered via the –48 Vdc backplane. The remote IDU has an internal universal AC power supply. The output of this power supply is –48 Vdc.. Each PCA in the IDU converts the –48 Vdc power feed to the voltages required for on-board use. The Motherboard converts the –48 Vdc power to the voltages it requires and the I/O modules use.
28 Draft: 8/13 PTM 1000 Operations and Maintenance Manual IFD Contribution The remote IDU uses three functions from the hub’s IFD PCA: the coax command channel (CCCH), the 15Mhz reference signa,l and the DC power couple and sense for the TRA. In the hub, the IFD PCA frequency multiplexes multiple MCA signals on to one coaxial cable. Since there is only one TRA on the remote, there is no need for the multiple IFs. The IFD also provides adjustable gain to the IF signals and the CCCH.
Chapter 2: System Description Draft: 8/13 29 Switching Power Supply The remote IDU is powered from 110Vac. The remote IDU has a built-in AC/DC power converter, which accepts 90-260 Vac, 50-60 Hz. The power unit is UL/CSA safety certified and uses a standard IEC power input connector. A fully loaded remote requires approximately 210W power. LEDs and Alarms The remote IDU has three LEDs – one red and two green.
30 Draft: 8/13 PTM 1000 Operations and Maintenance Manual Remote Outdoor Unit (ODU) The remote ODU consists of a single parabolic antenna with its associated interface electronics and mounting frame. The antenna assembly forms a single digital airlink interface. Figure 9 Remote ODU Transmit and Receive Assembly (TRA) The antenna electronics are contained in the Transmit and Receive PCA (TRX) and a millimeter-wave front end.
Chapter 2: System Description Draft: 8/13 31 • The on-board processor interfaces with the on-board phase lock loop ICs for initialization, control and monitoring, and also interfaces to on-board A/D and D/A converters for control and monitoring of variable filters, RF output power, and temperature sensing. • The TRA has a Receive Signal Strength Indicator (RSSI) to help align the antenna during installation.
Chapter 3 Grounding This Chapter describes the following: • General Requirements, page 34 • Hub Grounding, page 36 • Remote Grounding, page 39 Wavtrace™ PTM 1000 Operations and Maintenance Manual
34 Draft: 8/13 PTM 1000 Operations and Maintenance Manual General Requirements EMP Surge Protectors The EMP surge protectors must be installed in the correct orientation. For the surge protectors installed outdoors next to the transmit/receive antenna, the protected side is the side leading to the antenna/transceiver or ODB connection. For the surge protectors installed indoors next to the hub indoor electronic equipment, the protected sider is the side leading to the hub indoor electronics.
Chapter 3: Grounding Draft: 8/13 35 Building Ground All ground bars need to have a direct connection to building or earth ground via a single ground cable and bonded per NEC Sec. 250-G. In addition, verify that the building’s electrical ground is also bonded to the building ground system.
Draft: 8/13 36 PTM 1000 Operations and Maintenance Manual Hub Grounding The following paragraphs describe outdoor and indoor grounding for the hub. Use the following schematic in Figure 10 as a guide during installation and grounding. Outdoor Distribution Box SURGE PROTECTOR F TRX E TRX D TRX C TRX B TRX A TRX Hub EMP PROTECTOR AC EMP PROTECTOR TX PROTECTED SIDE SURGE PROTECTOR EMP PROTECTOR EMP PROTECTOR RX T1, ETC...
Chapter 3: Grounding Draft: 8/13 37 Hub Outdoor Grounding Requirements After installing the ground bar at the hub antenna frame location (see Figure 11), bond the ground bar to building ground. If the ground cable to building ground is terminated prior to running it back to the indoor installation location, a separate ground cable must be installed parallel to ground the signal cable every 100 feet and at all 90-degree (or more) bends.
38 Draft: 8/13 PTM 1000 Operations and Maintenance Manual Hub Indoor Grounding Requirements After installing the ODU ground bar at the hub indoor electronics location (see Figure 12), bond the ground bar to building ground. The wall-mounted channels for the building ground must withstand a 50lb downward load. Locate the IDU ground bar installation point as near as possible to the signal cable entry point.
Chapter 3: Grounding Draft: 8/13 39 Remote Grounding The following paragraphs describe outdoor and indoor grounding for the remote. Use the following schematic in Figure 10 as a guide during installation and grounding. AC SURGE PROTECTOR GROUND BAR REMOTE GROUND BAR EMP PROTECTOR EMP PROTECTOR TX/RX PROTECTED SIDE PROTECTED SIDE SURGE PROTECTOR T1, ETC...
40 Draft: 8/13 PTM 1000 Operations and Maintenance Manual Remote Outdoor Grounding Requirements After installing the ground bar at the remote antenna location (see Figure 14), bond the ground bar to the building ground. If the ground cable to the building ground is terminated prior to running it back to the indoor installation location, a separate ground cable must be installed parallel to ground the signal cable every 100 feet and at all 90-degree (or more) bends.
Chapter 3: Grounding Draft: 8/13 41 Remote Indoor Grounding Requirements After installing the ground bar at the remote indoor electronics location (see Figure 15), bond the ground bar to the building ground. The wall-mounted channels for the building ground must withstand a 50lb downward load. Locate the ground bar installation point as near as possible to the signal cable entry point. The signal cable coming from the indoor electronics must be connected to the protected side of the surge protector.
