Abstract: Systems and methods are provided for modularly constructing a software defined radio (“SDR”). Given an SDR kernel (i.e., a potentially platform-neutral definition of digital signal processing functionality and control operations necessary to implement the core portion of a software defined radio implementing a particular radio standard), an optional description of governmental regulations for a particular locality, and an interface harness providing the necessary components for interfacing to specific communication channels and devices (including SDR hardware components), an SDR factory component performs a process of constructing an SDR software component for implementing a particular radio standard on a particular host. The SDR software component may additionally construct components which restrict the operation of the resulting SDR software component.

Abstract: A multimedia conference technique is disclosed that allows physically remote users to participate in an immersive telecollaborative environment by synchronizing multiple data, images and sounds. The multimedia conference implementation provides users with the perception of being in the same room visually as well as acoustically according to an orientation plan which reflects each remote user's position within the multimedia conference environment.

Abstract: Malicious network node activity and, in particular, denial of service attacks, may be mitigated by one or more practical mitigation mechanisms and mitigation mechanism combinations. Suitable protocol messages may be challenged with a challenge probe. A response to the challenge probe may be utilized to determine if received protocol messages are illegitimate, that is, originated by a malicious network node. Received protocol messages may be classified as questionable protocol messages. For efficiency, protocol message challenges may be limited to protocol message classified as questionable. A sequence number limit may be calculated as a function of receive window size. Transmission control protocol messages may be determined to be illegitimate by comparing the acknowledgement number field with the calculated sequence number limit.

Abstract: A system for selecting a modulation scheme and an error correction coding scheme for each subchannel in an OFDM system based on the energy detected on that subchannel.

Abstract: A wireless station is connected to a wireless network through an access point and can establish a direct client-to-client connection to a second wireless station. The wireless station can communicate directly with the second wireless station without involving the access point. The wireless station communicates with the wired network and with other wireless stations through the access point. The second wireless station may have an infrastructure connection to the access point or may be independent.

Abstract: A wireless device that desires to be connected to a wireless network broadcasts itself and its capabilities to a network using an information element. The information element is provided with frames, such as management frames, in a channel that is not protected or encrypted. The information element is forwarded to one or more potential registrar devices. One of the registrar devices then provides configuration information to the enrollee, for example as a registrar information element. The configuration information may be passed out of band or in band, and may be passed using cryptography, which may involve public key cryptography, encryption with a PIN, or some other type of secure exchange.

Abstract: A method for authenticating and negotiating security parameters among two or more network devices is disclosed. The method has a plurality of modes including a plurality of messages exchanged between the two or more network devices. In a main mode, the two or more network devices establish a secure channel and select security parameters to be used during a quick mode and a user mode. In the quick mode, the two or more computers derive a set of keys to secure data sent according to a security protocol. The optional user mode provides a means of authenticating one or more users associated with the two or more network devices. A portion of the quick mode is conducted during the main mode thereby minimizing the plurality of messages that need to be exchanged between the initiator and the responder.

Abstract: A method of converting a peer name to a PNRP DNS is disclosed. The method may take a peer name and encode it into a common DNS name. The method may also take a PNRP DNS name and convert it to a peer name.

Abstract: A wireless station is connected to a wireless network through an access point and can establish a direct client-to-client connection to a second wireless station. The wireless station can communicate directly with the second wireless station without involving the access point. The wireless station communicates with the wired network and with other wireless stations through the access point. The second wireless station may have an infrastructure connection to the access point or may be independent.

Abstract: A method for authenticating and negotiating security parameters among two or more network devices is disclosed. The method has a plurality of modes including a plurality of messages exchanged between the two or more network devices. In a main mode, the two or more network devices establish a secure channel and select security parameters to be used during a quick mode and a user mode. In the quick mode, the two or more computers derive a set of keys to secure data sent according to a security protocol. The optional user mode provides a means of authenticating one or more users associated with the two or more network devices. A portion of the quick mode is conducted during the main mode thereby minimizing the plurality of messages that need to be exchanged between the initiator and the responder.

Abstract: A communication system in which an access point and one or more devices communicating through the access point adaptively apply Orthogonal Frequency Division Multiple Access (OFDMA). The access point may assign orthogonal subcarriers to devices as in conventional OFDMA, but the access point senses activity on the subcarriers and selects subcarriers without activity for assignment. In an alternative approach, a device that is configured for OFDMA communication may receive a channel assignment from a device that does not support OFDMA. The OFDMA-capable device may use only a portion of the subcarriers in the assigned channel, which may be communicated to the non-OFDMA device. During the non-OFDMA device may then ignore unused subcarriers in error detection and correction to avoid incorrectly classifying communications as erroneous.

Abstract: A computing device with a software defined radio. The software defined radio has an architecture with separate components to provide control functions and data processing functions. The control components configure the data processing components so that the software defined radio provides desired operating characteristics. To facilitate programming the software defined radio to communicate according to one or more wireless technologies, the computing device may include a library of wireless technology specifications. By accessing a technology specification in the library, the control components can determine an appropriate configuration of the data processing components for a selected wireless technology. The data processing components may be hardware or software and, if hardware and software components are available to perform a data processing function, the control components may select between the hardware and software components depending on throughput, processor loading or other criteria.

Abstract: A computing device with a configurable antenna. The antenna is configured through a switching circuit operating under software control. Operating characteristics of the antenna are configured based on connections between conducting segments established by the switching circuit, allowing the nominal frequency, bandwidth or other characteristics of the antenna to be configured. Because the switching is software controlled, the configurable antenna may be integrated with a software defined radio. The radio and antenna can be reconfigured to support communication according to different wireless technologies at different times or to interleave packets according to different wireless technologies to support concurrent sessions using different wireless technologies.

Abstract: A method and apparatus for fragmenting and reassembling IKE protocol data packets that exceed a Maximum Transmission Unit is provided. A transmitting node determines whether to fragment IKE data depending on whether the receiving node has the capability to receive and reassemble fragmented data packets. The transmitting node detects whether fragmentation is appropriate and then intercepts and fragments appropriate IKE payloads for transmission over a network. The invention further includes a method and apparatus for reassembling fragmented IKE payloads. The receiving node discards certain packets according to a set of predetermined rules that are designed to prevent denial of service attacks and other similar attacks. No modification is required to the existing IKE protocol or to other lower level networking protocols.

Abstract: A system and method of serverless peer-to-peer group management and maintenance is presented. Group formation and discovery of private, public, and enumerated groups are provided, as is a method of joining such a peer-to-peer group. Group information management provided by the present invention ensures that each node maintains a current database from the initial joining of the group through the run phase of membership. Group graph maintenance utilizes a group signature to ensure that partitions in a graph may be detected and repaired. The utility of connections within the graph are also monitored so that non-productive connections may be dropped to increase the efficiency of the group. The diameter of the graph is also monitored and adjusted to ensure rapid information transfer throughout the group. A disconnect procedure is used to maintain the graph integrity and prevent partitions resulting from the departure of a group member.

Abstract: A mechanism is provided to extend the range of wireless devices beyond the range limit that results from timing restrictions imposed by the IEEE 802.11 standard. The mechanism, which operates at the upper level of the 802.11 MAC, determines whether the wireless devices are far apart or not far apart. When the wireless devices are determined to be far apart, the standard retransmission protocol at the lower level of the 802.11 MAC is disabled and a custom ACK packet is utilized. Delivery of a transmitted packet is confirmed if the custom ACK packet is received within a maximum delay period that takes into account the longer propagation delay between wireless devices that are far apart.

Abstract: A system and method for providing the ability to discover the capabilities of a user's computer to determine whether it is capable of supporting more than one wireless protocol simultaneously is provided. A computing device's capabilities (including, for example, hardware and/or software capabilities) is checked to determine if it supports at least two specific wireless protocols and checking a computing device's capabilities (including, for example, hardware and/or software capabilities) is checked to determine if it supports both wireless protocols simultaneously. The techniques for determining the computing device's compatibility may include comparing lists of protocol requirements to lists of system capabilities and/or generating test signals by the system according to the protocol.

Abstract: Methods and apparatuses for Orthogonal Frequency-Division Multiplexing (OFDM) communication of non-OFDM radio signals are disclosed. The non-OFDM radio signals are force-modulated into OFDM signals. In one example, a non-OFDM signal is received and is processed into an OFDM signal to produce a created OFDM signal. An actual OFDM signal is also received and is processed together with the created OFDM signal.

Abstract: A multiuser scheme allowing for a number of users, sets of user, or carriers to share one or more channels is provided. In the invention, the available channel bandwidth is subdivided into a number of equal-bandwidth subchannels according to standard OFDM practice. A transmitter transmits data on a set of OFDM subchannels that need not be contiguous in the spectrum or belong to the same OFDM channel. A receiver receives and decodes the data and detects errors on subchannels. The receiver then broadcasts the identity of those subchannels on which the error rate exceeds a specific threshold, and the transmitter may select different subchannels for transmission based on this information.

Abstract: A method to negotiate computer settings in advance is presented. A prediction is made to determine if the computer setting will be needed, and if needed, whether a value outside of a normal range of values will be needed. A value for the computer setting that is outside of the normal range of values is determined and the value is set to the outside value. A value within the normal range of values is used if it was predicted that there is no need for a value outside of the normal range of values.