Abstract: A method of antenna alignment for a wireless mesh communications network (1) is disclosed. The method is applied to a mesh communications network (1) having a first plurality of communications nodes (2) interconnected by a second plurality of wireless communications links (3).

Abstract: A communications system comprises a transmitter, receiver and channel. The transmitter transmits multiple copies of each data bit in a multi-dimension modulation scheme matrix, the dimensions being selected from frequency, time and code. Each dimension is divided into sub-groups. A bit-loading method is used such that copies of each data bit (b11, b12, b13) are allocated within the matrix according to a predetermined arrangement so that within each dimension copies of the same data bit reside within different sub-groups.

Abstract: A communications system comprises a transmitter, receiver and channel. The transmitter transmits multiple copies of each data bit in a multi-dimension modulation scheme matrix, the dimensions being selected from frequency, time and code. Each dimension is divided into sub-groups. A bit-loading method is used such that copies of each data bit (b11, b12, b13) are allocated within the matrix according to a predetermined arrangement so that within each dimension copies of the same data bit reside within different sub-groups.

Abstract: In a transmitter of an orthogonal frequency division multiple access (OFDMA) system, a subchannelization module generates an OFDMA symbol with data on multiple subcarriers, from received incoming data packets. An input controller applies a first formula to determine a first index of each received data packet, and stores each received data packet at an address in memory according to its first index. An output controller applies a second formula to determine the nature of the data to be carried by each subcarrier in the OFDMA symbol and, if said second formula indicates that a data subcarrier should be output, reads the data from said memory, wherein said data packets are stored in said memory at addresses such that the data can be read out at least piecewise sequentially when generating the OFDMA symbol.

Abstract: One embodiment of the present invention provides a computationally efficient method to process a short training sequence in order to establish the presence of a valid packet on the medium and determine optimum sampling instance.

Abstract: A ranging code present in a transmission from a transmitter to a receiver can be detected, and hence a time offset can be determined. For each of the possible ranging codes in a transmitted signal, a correlation is formed between a received signal and the ranging code for multiple subcarriers in the received signal. For multiple adjacent ranging subcarriers, the correlation is multiplied by a conjugate of the correlation of an adjacent ranging subcarrier in order to form a differential phase value. At least one ranging code in the transmitted signal can then be determined based on the differential phase values for said plurality of subcarriers. A time offset in the transmission from the transmitter to the receiver can then be determined, based on the differential phase values for the subcarriers, and based on the determined ranging code.

Abstract: A ranging code present in a transmission from a transmitter to a receiver can be detected, and hence a time offset can be determined. For each of the possible ranging codes in a transmitted signal, a correlation is formed between a received signal and the ranging code for multiple subcarriers in the received signal. For multiple adjacent ranging subcarriers, the correlation is multiplied by a conjugate of the correlation of an adjacent ranging subcarrier in order to form a differential phase value. At least one ranging code in the transmitted signal can then be determined based on the differential phase values for said plurality of subcarriers. A time offset in the transmission from the transmitter to the receiver can then be determined, based on the differential phase values for the subcarriers, and based on the determined ranging code.

Abstract: In a transmitter of an orthogonal frequency division multiple access (OFDMA) system, a subchannelization module generates an OFDMA symbol with data on multiple subcarriers, from received incoming data packets. An input controller applies a first formula to determine a first index of each received data packet, and stores each received data packet at an address in memory according to its first index. An output controller applies a second formula to determine the nature of the data to be carried by each subcarrier in the OFDMA symbol and, if said second formula indicates that a data subcarrier should be output, reads the data from said memory, wherein said data packets are stored in said memory at addresses such that the data can be read out at least piecewise sequentially when generating the OFDMA symbol.

Abstract: A method of synchronizing an Orthogonal Frequency Division Multiplexed (OFDM) IEEE 802.11a data packet at a receiver is disclosed. The 802.11a data packet has a series of short training sequence (STS) symbols as a preamble. Cross-correlation at the receiver of the STS in the 802.11a packet PLCP preamble with the modified reference STS, that is 10 circular shifted by eight samples, results in a main correlation peak but with reduced pre- and post-lobes. To locate the cross-correlation peak, a running second derivative of the cross-correlation function is performed. Peak selection employs a running comparison of the position and magnitude of all peaks in the intermediate neighborhood of the local peaks. Following selection of a peak from within the cross-correlation function of the first STS in the PLOP preamble, both the position and magnitude of the first STS is compared to those of the second STS. Based on the two independent calculations, the start of the OFDM frame is estimated.

Abstract: A method of synchronising an Orthogonal Frequency Division Multiplexed (OFDM) IEEE 802.11a data packet at a receiver is disclosed. The 802.11a data packet has a series of short training sequence (STS) symbols as a preamble. Cross-correlation at the receiver of the STS in the 802.11a packet PLCP preamble with the modified reference STS, that is circular shifted by eight samples, results in a main correlation peak but with reduced pre- and post-lobes. To locate the cross-correlation peak, a running second derivative of the cross-correlation function is performed. Peak selection employs a running comparison of the position and magnitude of all peaks in the intermediate neighbourhood of the local peaks. Following selection of a peak from within the cross-correlation function of the first STS in the PLCP preamble, both the position and magnitude of the first STS is compared to those of the second STS. Based on the two independent calculations, the start of the OFDM frame is estimated.

Abstract: A method of synchronising an Orthogonal Frequency Division Multiplexed (OFDM) IEEE 802.11a data packet at a receiver is disclosed. The 802.11a data packet has a series of short training sequence (STS) symbols as a preamble. Cross-correlation at the receiver of the STS in the 802.11a packet PLCP preamble with the modified reference STS, that is circular shifted by eight samples, results in a main correlation peak but with reduced pre- and post-lobes. To locate the cross-correlation peak, a running second derivative of the cross-correlation function is performed. Peak selection employs a running comparison of the position and magnitude of all peaks in the intermediate neighbourhood of the local peaks. Following selection of a peak from within the cross-correlation function of the first STS in the PLCP preamble, both the position and magnitude of the first STS is compared to those of the second STS. Based on the two independent calculations, the start of the OFDM frame is estimated.

Abstract: A method and apparatus for exchanging data rate information across a packet-based network, is presented herein. In accordance with an embodiment of the invention, a first and second communication device, configured to operate as data sources, sinks, or both, communicate with a first and second gateway mechanism, respectively. The first gateway mechanism receives data rate information from the first communication device to determine a first data signaling rate between the first communication device and the first gateway mechanism. Similarly, the second gateway mechanism receives data rate information from the second communication device to determine a second data signaling rate between the second communication device and the second gateway mechanism. The first gateway forwards data rate information containing the first data signaling rate to the second gateway mechanism and the second gateway mechanism forwards data rate information containing the second data signaling rate to the first gateway mechanism.

Abstract: A method and apparatus for establishing communication between a sending facsimile machine and a receiving facsimile machine first receives an answer tone message for a specified time. It then is determined if a given joint menu message has been received from the receiving facsimile machine at any time during the specified time. If it is determined that the given joint menu message has not been received from the receiving facsimile machine at any time during the specified time, then the above noted alias joint menu message is forwarded to the sending facsimile machine. The alias joint menu message is different from the given joint menu signal and thus, not a true joint menu message that can be used by the sending facsimile machine.

Abstract: A method of synchronising an Orthogonal Frequency Division Multiplexed (OFDM) IEEE 802.11a data packet at a receiver is disclosed. The 802.11a data packet has a series of short training sequence (STS) symbols as a preamble. Cross-correlation at the receiver of the STS in the 802.11a packet PLCP preamble with the modified reference STS, that is circular shifted by eight samples, results in a main correlation peak but with reduced pre- and post-lobes.

Abstract: An apparatus and method of forwarding data from a sending node to a receiving node across a network first encapsulates non-time dependent data in specifically sized frames, and then transmits such encapsulated frames after frames with time dependent data are transmitted. More particularly, the data includes a set of time dependent data types and a set of non-time dependent data types. Each of the time dependent data types are specified (e.g., by their specific protocol specifications) to forward data in frames having a predefined frame size.

Abstract: A software defined radio (SDR) is based on flexible software architecture. This allows the radio equipment (e.g., user terminal, base stations etc.) to be reconfigured by downloading and implementing appropriate software. In other words, the radio equipment is software redefinable. As a result, an SDR can operate several different wireless communications standards, and also modify its behavior while remaining in a given standard. The present invention provides an operator entity, to allow the user to reconfigure the equipment as he desires, as an when required. A management module is also provided within software defined radio equipment, to operate the configuration of the equipment, according to network, operator and equipment requests and constraints.