Abstract: Systems and methods automatically compensate for long-term drift of frequency standards or references used by transmitting and receiver terminals to avoid manual adjustment of the terminals to bring them back within operating tolerances and minimize communications outages caused by inability of the system to otherwise accommodate for such drift. The present invention may provide automatic band selection to maintain a modulated carrier within an operating range of an automatic frequency control or tracking capability of a communication device. This may be accomplished by selecting an appropriate reference signal used to control a center frequency of an automatic frequency control circuit (such as a PLL) or used to convert the carrier frequency of the modulated carrier to fall within the operating range of the automatic frequency control circuit and/or by causing the transmitting station to at least partially correct the frequency discrepancy.

Abstract: A system and method for testing a radio network. A user at a central site may choose specific radios to be tested and specific test parameters for each one. The user may specify start and stop times, sample rates, whether one or multiple links are to be simultaneously tested, whether results should be presented as snap shots, statistical tables/graphs/charts, or as correlated data from multiple links. Distributed testing is permitted, in which the operational characteristics of one radio are varied, and another radio is monitored for a corresponding change. Once data has been gathered from one or more tests on one or more links, the data may be returned to the central site for analysis and presentation to the user in the selected format.

Abstract: The present invention relates in general to communication networks. In particular, the invention relates to a communication network in which nodes communicate via radio connections employing Ethernet protocol in a ring configuration which provides for fault tolerance and prevention of infinite communication loops. In a preferred embodiment, the network is in a ring configuration and comprises two routers for enabling fault tolerance in the event of a malfunctioning communication link and for preventing infinite message forwarding around the ring network. VLANS may be beneficially employed to assist with rerouting of data communication traffic in the event of a communication link failure and to aid in isolating customer network data from unauthorized viewing.

Abstract: A system and method are disclosed for planning the deployment of a plurality of receiver/transmitter pairs such that wireless communication links may be established meeting design criteria and allowing for the addition of future wireless communication links. A master planning tool is preferably provided which utilizes a simplified set of design rules in order to allow for the analysis of a large number of mutually interfered wireless communication links. Preferably, link analysis is accomplished in multiple orders of analysis, such as a master planning analysis, a wireless link design analysis, a field verification analysis, and/or an in-service analysis. Link planning according to the present invention provides for high density deployment of radios, such as for a urban area radio network.

Abstract: A system and method for transmitting specialized overhead data in the payload section of a standard communication frame such as a modem frame. The overhead data is added to the user payload data and the combination is presented to a communication interface, such as a modem, as payload-only data for transmission. A similar process at the receiving end extracts the overhead data from the payload data presented by the receiving communication interface. The overhead data can include information that is used to interpret the payload data and to identify which type of communications protocol it represents. The overhead data can also include network management information for use by a communications processor.

Abstract: A method of and apparatus incorporating 1+1 protection in a point-to-point radio system includes redundant microwave radio transceiver pairs, each transceiver including identical controls for identifying faults and reconfiguring to accommodate failures. Each transceiver includes receiver and transmitter monitoring circuitry for detecting a loss of received signal or transmitted signal, respectively. Fault signals are generated in response to loss of signal which are then processed by a designated master processor implementing a set of rules for identifying a likely failure corresponding to the faults detected. According to the rule, a partial loss of received signal by one of the receivers indicates a failure of that receiver, while loss of signal by both receivers is interpreted as a failure of the corresponding far-end transmitter. Conversely, receipt of a loss of signal message from a far-end radio station is interpreted as a failure of the active transmitter or the master controller.

Abstract: The system provides a distributed decentralized network architecture. Network routing is performed at each node in the network, as opposed to the centralized architecture's single POP. Each node is typically an access point to the network, and it collects the relevant traffic statistics for subscribers connecting at that node. This is accomplished by a network switching/control element contained within the (Invisible Fiber Unit) IFU. The information is collected from the switching/control element contained within the IFU. The information is collected from the switching element by the IFU's CPU. This information can then be pre-processed locally, or sent directly to a central billing facility, for further processing, eventually resulting in the creation of the subscriber's bill. Essentially, it is only billing information that flows back to a central point, rather than the data traffic itself.

Abstract: Distortion introduced into a multiamplitude signal format or amplitude and phase signal format by a high power microwave amplifier is compensated by a system which adapts itself to non-linearities present in the amplifier and predistorts the input signals before they are subjected to the non-linearities created by the amplifier. The degree of predistortion is non-fixed and varies or is updated as the non-linear conversion characteristics of the amplifier change with time. The distortion can also be compensated by using a power curve look-up table.