Eion LibraPlus 5845, User Manual, Page: 18 / 140

2.1.4.2. LibraPlus 5845 Adaptive Polling Protocol
The LibraPlus solves all the issues related to CSMA/CA by using a Proprietary Adaptive Polling RF
protocol that provides Media Access Control (MAC) for the Access Point and the remote users to ap-
propriately share the RF channel.
The Adaptive Polling Proprietary Protocol is a polling-based protocol. In brief, the Access Point per-
forms a central control on the RF channel by polling the remote users (subscribers) in a round-robin
fashion. If the polled user has data to send, then it immediately sends the data to the base station; oth-
erwise, it keeps silent, in which case the base station will timeout and then starts to poll the next user.
Remotes need not have a communication path between them. With this adaptive polling action occurring,
each station gets their opportunity to transmit data to the master station. This is done in a sequential
format, first remote station#1, then #2, then #3 etc. When all remotes have been given their opportunity
to communicate, the process repeats itself, again and again.
The LibraPlus 5845 uses intelligence to determine the number of polling cycles every user gets depend-
ing on the level of its activity. This way the network resources are not wasted during the polling of
inactive users due to no user data transmission. A mechanism is also provided for an inactive user to
become active and to resume its data transmission. The variation of polling cycles also has the potential
support greater total number of CPEs.
2.1.4.3. Access Point (AP) Equipment
The AP controls communication within the wireless network and is the main access point to the Eth-
ernet.
The access point communicates with the CPE’s in the system to provide each CPE with Access to the
main network (i.e. Ethernet). The access point is typically located at a distance away from the CPE
that will provide adequate radio signal strength for the specified data rates.
The Access Point is responsible for any CPE data management functions.
The LibraPlus AP consists of three parts: 1) AP radio unit, 2) Ethernet Power Inserter with CAT-5
cable (bought separately) and weatherproofing kit (included), and 3) the External Antenna and cable
(both bought separately).
• LibraPlus AP. The AP is the main piece of radio equipment. It is designed for outdoor installation
but can also be installed indoors if needed. The AP is equipped with an N-type (F) RF connector so
that the external antenna can be connected to it. Thus many different types of base stations can be
deployed using sectoral, omni or other specialized antennas.
• Ethernet Power Inserter. This piece of equipment is a small box that connects between the
CPE and the P.C. This box also provides power for the AP equipment to run. A CAT-5 outdoor
cable is used to connect the Power inserter to the AP. The weatherproofing kit is used with standard
RJ-45 connector to ensure reliable connection for outdoor systems.
• Antenna and Cable. In order to accommodate different frequency re-use plans and scalability
of the base stations the AP is designed to be used with an external antenna. Antennas and cables are
selected by the user based on the network requirements.
2.1.4.4. Customer Premise Equipment (CPE)
The CPE equipment connects customers to the AP via a wireless link. The link enables customers to
communicate with other users of the wireless network and the Ethernet. Customer Premise Equipment
has two parts: 1) CPE radio unit and 2) Ethernet Power Inserter with CAT-5 cable (bought separately)
and weatherproofing kit (included).
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Description