Abstract: A demodulator for a digital radio receiver comprises a frequency discriminator and a Viterbi decoder. The frequency discriminator receives a series digital signal samples representative of an FSK-modulated signal and performs frequency discrimination on the digital signal samples to generate a series of frequency samples. Each frequency sample represents an instantaneous frequency of the signal in a respective frequency-sample period. There are an integer oversampling factor, N>1, of frequency-sample periods in each symbol period. The Viterbi decoder receives the series of frequency samples, determines branch metrics for each symbol period by determining distances between a vector of N successive frequency samples and each of a plurality of reference waveform vectors, each comprising N elements. It use the branch metrics in a Viterbi process to output demodulated symbol values corresponding to a maximum-likelihood decoding of the FSK-modulated signal.

Abstract: A method and system for managing Digital to Time Conversion (DTC) is provided. The method comprises receiving a first Radio Frequency (RF) signal and a second RF signal. The second RF signal is a phase-shifted first RF signal. The method further comprises converting the first RF signal to a first Intermediate Frequency (IF) signal and the second RF signal to a second IF signal. Further, a time delay between the first IF signal and the second IF signal is estimated based on a time difference measurement technique. The second RF signal is processed based on the estimated time delay to compensate for a delay error associated with the second RF signal.

Abstract: A method, system and apparatus for managing communication in a Public Safety Communication Network (PSCN). The PSCN includes a plurality of Mobile Stations (MSs) (110, 115, 120) and a master controller (105). The method includes initiating a communication between one or more MSs and the master controller using a primary channel (405). The primary channel corresponds to a primary frequency spectrum in the PSCN. The method further includes identifying one or more available channels in one or more of the primary frequency spectrum and a secondary frequency spectrum (410). Each of the primary frequency spectrum and the secondary frequency spectrum include one or more channels. Thereafter, a channel hopping pattern is generated for one or more MSs based on one or more available channels (415). The channel hopping pattern corresponds to a sequence of frequency hops for a MS.

Abstract: A wireless communication network is provided in which a plurality of radio devices achieve frequency diversity. By utilizing cognitive capability within the radio devices to iteratively select frequency sets, a lowest cardinality frequency set is generated and used to communicate amongst the plurality of radio devices. Each radio device can have different hardware, as the iterative selection of frequency set can take into account the different hardware capabilities of the radio devices.

Abstract: A method, system and apparatus for managing communication in a Public Safety Communication Network (PSCN). The PSCN includes a plurality of Mobile Stations (MSs) (110, 115, 120) and a master controller (105). The method includes initiating a communication between one or more MSs and the master controller using a primary channel (405). The primary channel corresponds to a primary frequency spectrum in the PSCN. The method further includes identifying one or more available channels in one or more of the primary frequency spectrum and a secondary frequency spectrum (410). Each of the primary frequency spectrum and the secondary frequency spectrum include one or more channels. Thereafter, a channel hopping pattern is generated for one or more MSs based on one or more available channels (415). The channel hopping pattern corresponds to a sequence of frequency hops for a MS.

Abstract: A wireless communication network is provided in which a plurality of radio devices achieve frequency diversity. By utilizing cognitive capability within the radio devices to iteratively select frequency sets, a lowest cardinality frequency set is generated and used to communicate amongst the plurality of radio devices. Each radio device can have different hardware, as the iterative selection of frequency set can take into account the different hardware capabilities of the radio devices.

Abstract: A method and system for managing Digital to Time Conversion (DTC) is provided. The method comprises receiving a first Radio Frequency (RF) signal and a second RF signal. The second RF signal is a phase-shifted first RF signal. The method further comprises converting the first RF signal to a first Intermediate Frequency (IF) signal and the second RF signal to a second IF signal. Further, a time delay between the first IF signal and the second IF signal is estimated based on a time difference measurement technique. The second RF signal is processed based on the estimated time delay to compensate for a delay error associated with the second RF signal.

Abstract: A time trigger for instruction execution can be contained within the instruction itself. A time stamp value associated with each of a sequence of instructions, which are written into a FIFO memory (9) by an application specific controller (1), is compared with the output value of a counter (11). When the two values are equal, a comparator 10 sends a command to an instruction decoder (8) to execute the current instruction. The invention has the advantage of a reduced interrupt overhead and his particular application to HiperLAN 2 systems in which it can be incorporated without affecting the protocol handling.

Abstract: A Viterbi decoder includes a number of classical Add-Compare-Select units and a number of further Add-Compare-Select unit having a lower complexity butterfly unit (300) having only two adder means, such that the further Add-Compare-Select unit has a butterfly unit (300) comprising: first adder means (310) for receiving a first path metric and a branch metric and for producing at its output the addition thereof; and second adder means (320) for receiving a second path metric and said branch metric and for producing at its output the addition thereof. First comparator means (330) are coupled to receive the output of the second adder means and coupled to receive the first path metric for comparing therebetween. Second comparator means (340) are coupled to receive the output of the first adder means and coupled to receive the second path metric for comparing therebetween.

Abstract: A Viterbi decoder including an Add-Select-Compare unit with a new butterfly unit (300) having only two adders (310, 320), compared with a conventional butterfly unit's four adders, for processing a trellis transition having branch metric of zero. The new butterfly unit (300) is thus of reduced complexity (saving 8% of the total Viterbi decoder complexity in a typical example).