WiLAN

About: WiLAN is a company organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Computer science & Biology. The organization has 155 authors who have published 171 publications receiving 5852 citations.

Method and apparatus for multiple access between transceivers in wireless communications using ofdm spread spectrum

Abstract: A method for allowing a number of wireless transceivers to exchange information (data, voice or video) with each other. A first frame of information is multiplexed over a number of wideband frequency bands at a first transceiver, and the information transmitted to a second transceiver. The information is received and processed at the second transceiver. The information is differentially encoded using phase shift keying. In addition, after a pre-selected time interval, the first transceiver may transmit again. During the preselected time interval, the second transceiver may exchange information with another transceiver in a time duplex fashion. The processing of the signal at the second transceiver may include estimating the phase differential of the transmitted signal and pre-distorting the transmitted signal. A transceiver includes an encoder for encoding information, a wideband frequency division multiplexer for multiplexing the information onto wideband frequency voice channels, and a local oscillator for upconverting the multiplexed information. The apparatus may include a processor for applying a Fourier transform to the multiplexed information to bring the information into the time domain for transmission.

Method and System For Adaptively Obtaining Bandwidth Allocation Requests

Abstract: A method and apparatus for adaptively obtaining bandwidth requests in a broadband wireless communication system. The method and apparatus includes dynamically varying technique combinations enabling a plurality of users to efficiently request bandwidth from a shared base station. A user may “piggyback” a new bandwidth request upon, or set a “poll-me bit” within, presently allocated bandwidth. A base station may poll users, individually or in groups, by allocating unrequested bandwidth for new requests. Polling may respond to a “poll-me bit,” and/or it may be adaptively periodic at a rate based on communication status parameters, such as recent communication activity and connection QoS levels. Group polling permits a possibility of collisions. Polling policies may be established for dynamically varying user groups, or may be determined for each user. Dynamic selection of appropriate polling techniques makes use of efficiency benefits associated with each technique.

Scalable wireless network topology systems and methods

Abstract: Wireless broadband data access is provided to and from a plurality of locations distributed randomly over a large geographic area. The network can be deployed one node at a time, with a new node incorporated into the network if within radio frequency range of any existing node in the network. The newly incorporated node can then be the attaching point for another new node that requires incorporation into the network. Data can be forwarded over multiple hops to reach its destination in the network, with the data-polling scheme self-synchronizing with minimal transmission overhead.

Multicode direct sequence spread spectrum

Abstract: In this patent, we present MultiCode Direct Sequence Spread Spectrum (MC-DSSS) which is a modulation scheme that assigns up to N DSSS codes to an individual user where N is the number of chips per DSSS code. When viewed as DSSS, MC-DSSS requires up to N correlators (or equivalently up to N Matched Filters) at the receiver with a complexity of the order of N2 operations. In addition, a non ideal communication channel can cause InterCode Interference (ICI), i.e., interference between the N DSSS codes. In this patent, we introduce new DSSS codes, which we refer to as the "MC" codes. Such codes allow the information in a MC-DSSS signal to be decoded in a sequence of low complexity parallel operations which reduce the ICI. In addition to low complexity decoding and reduced ICI. MC-DSSS using the MC codes has the following advantages: (1) it does not require the stringent synchronization DSSS requires, (2) it does not require the stringent carrier recovery DSSS requires and (3) it is spectrally efficient.

Adaptive call admission control for use in a wireless communication system

Abstract: The invention relates to communication systems and to systems and methods for implementing adaptive call admission control (CAC) in such systems. Adaptive call admission control can determine what CPE to base station calls (connections) are allowed at any given time. CAC, coupled with precedence, can further determine what connections are suspended if less bandwidth is available than is currently committed. Multiple techniques are disclosed to select connections for suspension. These techniques include suspending enough connections through the affected CPE until there is enough bandwidth to meet the remaining commitment, randomly (or in a round robin fashion) choosing connection to suspend from the entire set of connection, and using precedence priority levels.