Abstract: A physical layer convergence protocol (PLCP) data structure (300) transmitted in a multiple-input-multiple-output (MIMO) communication system. The PLCP data structure comprises a legacy portion including a legacy preamble (311) and a legacy header (312), wherein the legacy preamble (311) and the legacy header (312) carry information compliant with at least a WiMedia standard; and a high throughput (HT) portion including a HT preamble (321) and a HT header (322), and wherein the HT preamble (321) carries information enabling a receiver of the MIMO communication system to decode received signals.

Abstract: A multi-band communication system (400). The system includes a plurality of transmit channels (420-1, 420-N), wherein each transmit channel (420-X) transmits data streams through a single sub-band; and a plurality of receive channels (460-1, 460-N), wherein each receive channel (460-X) receives data streams of a single sub-band. In an embodiment of the invention, each transmit channel (420-X) and its respective receive channel (460-X) are configured with a different set of channel codes to encode and decode the data. The set of channel codes is determine by an more channel codes adaptive modulation coding (AMC) controller (461-X) based on the condition of the link between a transmit channel (420-X) and a receive channel (460-X).

Abstract: The system (900), transmitter (700), receiver (800.a 800.b), and method of the present invention provide a technique to code data bits into symbols using TCM, MLCM or BIMLCM before the symbols are placed in an SCBT block. Generally, TCM, MLCM, and BIMLCM do not have good performance over the frequency selective channels. However, since the frequency domain equalization of SCBT will flatten the channel, the use of TCM, MLCM and BIMLCM can provide significant gain. Furthermore, since some of the bits are left uncoded, the speed requirements on the encoder and decoder can be relaxed. This feature is especially important for the very high data rate systems.

Abstract: A wireless device (100) communicates in a wireless network, and executes a wireless device discovery process to discover other wireless devices (100) in the wireless network. In the wireless device discovery process, the wireless device (100) sets its antenna pattern to have an omnidirectional antenna pattern (202), and transmits a first packet (300) using the omnidirectional antenna pattern (202). The first packet (300) comprises a packet preamble sequence (310) formed by repeating each sample of a synchronization sequence N times (N>1). The remainder (320) of the first packet (300) is formed by spreading each sample thereof with a spreading factor P (P>1). For normal data communications, the wireless device (100) sets the antenna pattern to have a directional antenna pattern (204), and transmits a second packet using the directional antenna pattern (204).

Abstract: A Communications base-station configured to operate as a hub in a wireless network and provide communication services to a set of remote customer devices using a wireless protocol is disclosed. The communications base-station includes an antenna array having a plurality of antennae arranged in a fashion as to enable the antenna array to transmit and receive wireless signals in both a substantially omnidirectional and non-omnidirectional pattern, a physical layer (PHY) device coupled to the antenna array and configured to transmit and receive wireless signals and a media access control (MAC) device coupled to the PHY device and configured to direct the antenna array to concurrently provide beamformed wireless signals to a first customer device and omnidirectional wireless signals to second customer device.

Abstract: A wireless network (300) operates with at least two different types of wireless devices, including Type-A wireless devices (320) that communicate using a first transmission scheme and Type-B wireless devices (310) that communicate using a second transmission scheme. Type-A wireless devices (320) can transmit Type-A beacons (325) using the first transmission scheme. Type-B wireless devices (310) can transmit and receive Type-B beacons (315) using the second transmission scheme. Type-B wireless devices (310) can also transmit Type-A beacons (325) using the first transmission scheme, but cannot receive the Type-A beacons (325). Before establishing communications in a new channel, a Type-B wireless device (310) performs power sensing to detect the presence of any non-Type-B wireless devices (200), and if such wireless devices (200) are detected, it switches to another channel. Otherwise, it transmits a Type-A beacon (325) and a Type-B beacon (315) to establish communications in the channel.

Abstract: A wireless communication system performs high-speed transmission of information signals by using a multi-band approach. Each band spans about 500MHz. A flexible modulation scheme within each band employs time, amplitude and phase modulations, allowing adaptation of the data rate to the sub-band conditions. In addition, pseudo-random frequency sequence is employed to provide sufficient multi-user interference reduction.

Abstract: A method for detecting the presence of a television signal embedded in a received signal including the television signal and noise is disclosed. Either first-order or second order cyclostationary property of the signals may be used for their detection. When the first-order cyclostationary property is used, the following method is used, the method comprising the steps of upsampling the received signal by a factor of N, performing a synchronous averaging of a set of M segments of the upsampled received signal, performing an autocorrelation of the signal; and detecting the presence of peaks in the output of the autocorrelation function. When the second order cyclostationary property of the signal is used, the method comprising the steps of delaying the received signal by a fixed delay (symbol time), multiplying the received signal with the delayed version, looking for a tone (single frequency) in the output.

Abstract: A Single Carrier Block Transmission (SCBT) system employs an inherently parallel approach to error correction processing. At the transmission system (200), an incoming data stream is split (210) into P parallel data streams, each having a data rate equal to a fraction of the incoming data stream's data rate. The parallel data streams are then each separately encoded (220) in P parallel encoding processes (beneficially, using P parallel encoders (222)). The P separately encoded data streams are then merged (330), interleaved (320), and mapped (310) into a single stream of encoded symbols, which are transmitted to the receiver using an arbitrary modulation (240) and transmission scheme. At the receiver (255), the received data stream is de-interleaved (350) and split into P encoded data streams, which are then decoded (285) using P parallel decoders. Then, the decoded data streams are combined or multiplexed (295) into a single data stream.

Abstract: The system (700), apparatus (600), and method of the present invention provide an hierarchical pseudo-circularly symmetric and full circularly symmetric training sequence structure (100) for high-speed communication system. The hieratical pseudo-circularly symmetric part (101) is preferably used for burst detection, coarse frequency and timing error estimation and AGC gain setting. The full circularly symmetric part (102) is preferably used for channel estimation, fine frequency error estimation. The resulting sequence has a very good peak-to-average power (PAPR) property, making it suitable for many applications. The bandwidth efficiency is also improved due to using symmetric sequences.

Abstract: A system and method is provided for improved frequency error estimation in a high-frequency data communication system. In an embodiment, a method for providing improved frequency error estimation comprises performing encoding, interleaving and symbol mapping on original information bits to form a data stream of modulated information symbols; inserting pilot symbols into the data stream at progressively longer time intervals and transmitting the data stream as a radio signal from a data transmitter to a receiver. The method further comprises using the received pilot symbols, transmitted at progressively longer time intervals to perform frequency error estimation. In certain embodiments, the received pilot symbols may also be used to perform improved channel estimation updates.

Abstract: A flexible digital transmission system that improves upon the ATSC A/53 HDTV signal transmission standard. The system includes a digital signal transmitter for generating a first Advanced Television Systems Committee (ATSC) standard encoded 8-VSB bit stream and, for generating an encoded new robust bit stream for transmitting high priority information bits, wherein symbols of the new bit stream are capable of being transmitted according to a transmission mode including: a 2-VSB mode and a 4-VSB transmission mode. The standard 8-VSB bit stream and new bit stream may be simultaneously transmitted over a terrestrial channel according to a broadcaster defined bit-rate ratio. The transmission system includes a control mechanism for generating information needed for encoding robust packets at a transmitter device. It also includes a mechanism for encoding control parameters and multiplexes the generated information with the standard and robust bit-streams for transmission.

Abstract: A system and method for efficient transmission of different types of source data in the same packet, hence, enabling efficient transmission of multimedia and data content with unequal error protection are provided. The present disclosure defines a packet structure where the packet consists of a number of segments or payloads. The packet includes a field indicative of a number of payloads included in the packet; and at least one data field for each payload in the packet, the at least one data field defining at least one characteristic of the payload. The at least one data field includes a length of the payload, modulation and coding scheme, existence of a frame check sum (FCS), and existence of a midamble. The at least one data field may further include a continuation element indicative of whether two consecutive payloads are portions of a same data frame.

Abstract: The present invention provides a system (900), apparatus (700, 800) and method for frames, preambles and control headers for a physical (PHY) layer of the 802.22 WRAN specification. Some of the main features of the present invention include: Superframe and Frame structure; Superframe Preamble (and CBP Preamble); Frame Preamble; Superframe Control Header (SCH); and Frame Control Header (FCH).

Abstract: A method and system for efficiently utilizing frequency spectrum resources is disclosed. The method comprises the steps of determining at least one spectrum opportunity (510), wherein the opportunity is identified by a frequency range and a time duration, determining a set of altered transmission characteristics (515, 517) to allow transmission of a desired signal in the identified frequency range, wherein the altered transmission characteristics avoid interference with signals expected in the frequency range, and transmitting said desired signal using the altered transmission characteristics when the transmission occurs during said time duration. In one aspect of the system, the step of determining at least one opportunity comprises the steps of receiving signals in known frequency ranges, and determining the characteristics of the received signals.

Abstract: A single carrier modulation scheme suitable for use in high frequency communication systems is provided that achieves improved residual frequency error and phase noise estimation. At a transmitter, cyclically orthogonal constant amplitude pilot signals are inserted at the beginning (or end) of a plurality of SCBT blocks of a block coded data stream. At a receiver, a phase rotation of the received data stream is determined to remove a residual frequency error or to estimate the phase noise.

Abstract: A method and system of calculating debt service capacity of a loan applicant includes capturing, indexing, reclassifying and grouping transaction data and profile data of the loan applicant. Next, capturing a loan structure, risk factors, financial variables and reconciliation rules and finally using the aforementioned and loan applicants' data and cash flow projections to calculate loan applicants' debt service capacity with time value of money calculations.

Abstract: A method for generating preamble structures to be used in multi-mode wireless communication systems. The method includes generating a basic element sequence in a predefined length, wherein the basic element sequence has a circularly orthogonal property; generating a type-A preamble by repeating the basic element sequence a number of predefined times; and generating a type-B preamble by adding respective values of real parts to values of imaginary parts of elements in the type-A preamble. The type-A preamble and type-B preamble are cross-correlated.

Abstract: A method (200) and system (300) for detecting temporarily available bandwidth in a frequency band: select (205) a channel in the frequency band; measure (210) an energy received in the selected channel; compare (215) the measured energy to a first threshold; when the measured energy exceeds the first threshold, determine that the channel is unavailable (220) for transmission, otherwise determine (225) that the channel is available for transmission; correlate (255) a signal received in the channel with a known feature of a signal conforming to a particular transmission format; compare (260) the correlation result to a second threshold; when the correlation result in the channel exceeds the second threshold, determine (265) that a signal conforming to the particular transmission format is present in the channel, otherwise determine (270) that the signal conforming to the particular transmission format is not present in the channel.

Abstract: A system (100) and method (300) detect the presence of a narrowband signal having a bandwidth ?F2 in a wideband frequency channel having a band-width ?F1>?F2. The method (300) includes digitizing (310) a signal received in the frequency channel; transforming (320) the digitized signal into N digital frequency domain components; averaging (330) the power spectrum of the N digital frequency domain components over a plurality of samples; filtering (340) the averaged power spectrum of the N digital frequency domain components with a filter having M non-zero values spanning a bandwidth, ?F3, where N>M and ?F1>?F3; computing (350) a mean, ?k, a modified standard deviation, ?k, and a peak value, PMAX of the filtered, averaged power; and detecting (360) the presence of the narrowband whenever PMAX >(k1*?k)+(k2*?k), where k1 and k2 are selected to provide a probability of detection, a probability of missed detection, and a probability of false alarm.