Abstract: The invention provides methods and systems for channel estimation. A method comprises receiving a plurality of signal frames, comprising at least a first zone and a second zone, from a plurality of base stations in the wireless communication system. Two or more first delay profiles corresponding to two or more base stations are determined using the first zone. The method further comprising detecting at least one aliased tap in a time domain channel response of the second zone using the two or more first delay profiles. Another method comprises receiving a signal frame, comprising at least a preamble symbol and a data part, from a base station. A first delay profile corresponding to the preamble symbol is determined and a second delay profile corresponding to the data part is obtained. The first delay profile is analyzed in conjunction with the second delay profile to detect one or more aliased taps in a time domain channel response of the data part. The detected one or more aliased taps are nulled/rectified.

Abstract: A method and apparatus for estimating frequency offset and timing offset of a first Mobile Station (MS) in a communication system is provided. The method includes receiving a composite signal at a plurality of receiver antennas of a Base Transceiver Station (BTS). The composite signal includes a first signal transmitted from a first MS and a second signal transmitted from a second MS. The composite signal includes one or more tiles. Each tile includes a plurality of data sub-carriers, a plurality of first pilot sub-carriers, and a plurality of second pilot sub-carriers. A total phase offset of the first MS is estimated based on a complex conjugate product of pilot symbols of the plurality of first pilot sub-carriers. Thereafter, a first phase offset corresponding to the timing offset of the first MS is estimated based on a Power Delay Profile (PDP) of one or more first pilot sub-carriers.

Abstract: Methods of allocating a plurality of periodically distributed frames of communication between a first wireless transceiver and a second wireless transceiver are disclosed. One method includes detecting periodic data for transmission between the wireless base station and the wireless mobile unit. A transmission map that maps frequency and time slots is generated for transmission of the data packets. Allocation information is included within less than all of a plurality of transmission maps of the plurality of periodically distributed frames. The allocation information designates frequency and time slots in which data packets identified as a periodic data type are transmitted to the second wireless transceiver for the plurality of periodically distributed frames.

Abstract: Embodiments are directed to a wireless receiver system that utilizes a special structure of pilot symbols used for synchronization and channel estimation in transmission packets to measure noise power at the receiver. The periodicity of the pilot signal sequences is used to extract the noise power from the received signal. Such extraction is achieved by subtracting the received signals from two pilot slots which are separated by the known periodicity of the training sequence. This method relies on the fact that desired signal and system interference signals will cancel out after the subtraction process. Measuring the power of the residual signal after subtraction represents the estimate of the noise power. Several consecutive such residual signals can be first summed up before measuring the power to improve the estimate of the noise power at the receiver.

Abstract: Methods and systems for testing a software program are provided. The methods include receiving a textual input for testing at least one static type used by the software program. The textual input of an embodiment is pre-linked to the at least one static type. The method includes creating a dynamic type based on the textual input in a dynamically typed language. The dynamic type is populated based on a predefined set of test vectors and is then passed on to the software program. The software program is executed using the dynamic type. Executing the software program by using the dynamic type invokes the at least one static type used by the software program.

Abstract: A method and system of estimating frequency offset at a subscriber station is disclosed. The method includes the subscriber station receiving a composite signal, in which the composite signal includes multi-carrier signals transmitted from a plurality of base stations. The subscriber station selects a subset of the plurality of base stations. The subscriber station selects at least one pair of multi-carrier symbols of the composite signal, wherein each of the at least one pair of multi-carrier symbols include a plurality of pilot sub-carriers. The subscriber station selects a subset of the plurality of pilot sub-carriers of the at least one pair of multi-carrier symbols based on transmit pilot symbols of the pilot sub-carriers of the multi-carrier signals transmitted by the subset of the plurality of base stations.

Abstract: Embodiments for methods and apparatuses for processing a multi-carrier signal are disclosed. One method includes shaping a frequency spectrum of a multi-carrier transmit signal wherein an amplitude of a plurality of subcarriers of the multi-carrier transmit signal is increased relative to at least one other subcarrier of the multi-carrier transmit signal. The shaped frequency spectrum multi-carrier transmit signal is amplified with a power amplifier, wherein a power level of an output of the power amplifier is greater than a rated power level of the power amplifier.

Abstract: Methods of managing storage of HARQ packets are disclosed. One method includes a wireless device receiving variable length HARQ packets. The wireless device performing an error check on each received variable length HARQ packet, and storing within HARQ memory the HARQ packets that fail the error check. Each failed HARQ packet is stored in the HARQ memory by dividing the HARQ packet into HARQ sub-packets, and storing each HARQ sub-packet. The storage locations and storage order of each of the HARQ sub-packets are recorded for future retrieval.

Abstract: A method and system of training a communication system is disclosed. The method includes a first transceiver transmitting signals through one or more antennas of the first transceiver. A second transceiver selects a subset of a plurality of antennas of the second transceiver, wherein the selected subset provides a largest aggregate received signal power. The second transceiver transmits pilots on a subset of sub-carriers of multi-carrier signals through the selected subset of the plurality of antennas of the second transceiver. The first transceiver receives the pilots, and extracts channel knowledge from the received pilots.

Abstract: Embodiments described herein include methods for improving the SINR, and therefore communication quality or rate, in the downlink of a cellular communication system. In an embodiment, the system is an orthogonal-frequency-division multiple-access (OFDMA) system. In an embodiment, a set of terminals is designated a coordinated-transmission group. The set of terminal is chosen such that the slot-allocations of the set are given special treatment to alleviate interference from other sectors or cells. In an embodiment, “zones” defined in the WiMax standard are “repurposed” to handle the coordinated-transmission, although the zone was originally intended for another purpose.

Abstract: A method and system for managing memory using Hybrid Automatic Repeat Request in a communication system is provided. The method includes storing a retransmitted burst in a memory. The retransmitted burst includes plurality of bits. One or more of memory address of the retransmitted burst and the information corresponding to the retransmitted burst is recorded in a location table. The location table records memory addresses and the information corresponding to a plurality of bursts stored in the memory. The method further includes determining one or more preceding bursts corresponding to the retransmitted burst stored in the memory using location table. Thereafter, a combined burst is generated using the retransmitted burst and one or more preceding burst, if one or more preceding bursts corresponding to the retransmitted burst are stored in the memory. The combined burst includes the plurality of bits.

Abstract: Systems and methods are provided for improving a channel estimate in a signal communication system. The systems and methods improve the channel estimation quality and/or the delay spread of the channels that can be estimated. The combining of symbols operates to increase the density of pilots that are processed to provide the channel estimate.

Abstract: Embodiments described herein include methods for improving the SINR, and therefore communication quality or rate, in the downlink of a cellular communication system. In an embodiment, the system is an orthogonal-frequency-division multiple-access (OFDMA) system. In an embodiment, a set of terminals is designated a coordinated-transmission group. The set of terminal is chosen such that the slot-allocations of the set are given special treatment to alleviate interference from other sectors or cells. All terminals within a coordination group generally use the same slot, but embodiments are not so limited.

Abstract: Methods and systems for determining a Log-Likelihood Ratio (LLR) corresponding to each bit of a symbol are provided. The symbol comprises a predefined number of bits based on a predetermined constellation. The methods and systems include expanding the predetermined constellation. The predetermined constellation comprises a plurality of constellation-points wherein each constellation-point has a unique X co-ordinate and Y co-ordinate. Also, the expanded predetermined constellation further comprises points corresponding to each combination of the X co-ordinate and the Y co-ordinate of the constellation-points. The methods and systems further include calculating the LLR corresponding to each bit of the symbol based on the expanded predetermined constellation.

Abstract: Communication systems and methods are described in which multiple transmit signals are generated from an input stream or signal. The communication systems and methods, collectively referred to as antenna virtualization or virtual antenna systems, generate from each input stream multiple transmit signals that when driven into multiple antennas create a radiation pattern that effectively appears to originate from a single antenna. The communications operations include receiving at least one input stream. Multiple transmit signals are generated from the received input stream; the number of transmit signals generated is greater than the number of received input streams. Generation of the transmit signals involves transforming the input stream. The transforming includes applying one or more of a variable delay, a phase shift, and signal shaping to information of the input stream. The transmit signals are transmitted by a separate antenna of an antenna system.

Abstract: Methods and systems for estimating channel of one or more MSs in a collaborative MIMO communication system are provided. The method includes receiving a signal transmitted from a transmit antenna of a first MS and a transmit antenna of a second MS at a BTS using one or more receiver antennas. The method further includes computing one or more conjugate products for each of the first MS and the second MS using the signal. Thereafter, an average is determined over the plurality of receiver antennas and the plurality of tiles of the plurality of conjugate products for each of the first MS and the second MS. A phase determined based on the average of the plurality of conjugate products for the first MS and the second MS is divided into a first phase and a second phase for each of the first MS and the second MS. Additionally, the method includes determining a channel estimate for each tile of the first MS and the second MS at each receiver antennas.

Abstract: Embodiments are directed to a link adaptation method that selects the optimum transmission scheme and modulation and coding signal (MCS) level within a MIMO system, based on optimal maximum throughput on the channels. The method selects the MCS levels and spatial rate values for broadband communication systems based on the instantaneous broadband MIMO-OFDM signaling capacities. The transmission rate over the transmission channel is selected based on a comparison of the capacities achieved under diversity coding and spatial multiplexing MIMO transmission schemes. The effect of a particular receiver type or implementation can also be factored into the signaling capacity. For a fixed target probability of error, the scheme or spatial rate that has the higher instantaneous throughput is selected for transmission.

Abstract: A method and apparatus of a mobile subscriber (MS) estimating position are disclosed. One method includes the MS receiving at least one satellite transmitted signal with a first receiver, and estimating a time of arrival of the at least one satellite transmitted signal. The MS additionally receives at least one terrestrial base station signal with a second receiver, and estimates a time of arrival of the at least one terrestrial base station signal. The MS estimates its position based on the estimated time of arrival of the at least one satellite transmitted signal and the estimated time of arrival of the at least one terrestrial base station signal.

Abstract: A communication system is provided that includes signal encoding in a multiple input multiple output system. The communication system includes wireless communication networks. The communication system includes methods of encoding and transmitting symbols in a rate-1 complex symbol per second per Hertz transmission system while achieving maximum diversity. The communication further includes methods of interleaving the complex symbols such that each interleaved symbol comprises information of at least two complex symbols where the complex symbols obtain values from a rotated constellation.

Abstract: Methods and systems for performing channel estimation in a multiple antenna block transmission system are provided so as to improve the channel estimation quality and/or the delay spread of the channels that can be estimated.