Patent application number | Description | Published |
20080273582 | SELECTION OF ACQUISITION SEQUENCES FOR OPTIMAL FREQUENCY OFFSET ESTIMATION - Systems and methods are provided to generate a set of synchronization channel sequences that optimize time and frequency acquisition. A set of root indices of Zadoff-Chu sequences in a first domain (e.g., time domain) that optimize a performance metric or merit factor are identified. An optimal index is determined that also optimizes a performance metric in a reciprocal domain (e.g., frequency domain). Optimal indices satisfy a centro-symmetric relationship with respect to a half-value of sequence length: When 1 is an optimal index, N−1 is also an optimal root index. For sequences of length Q | 11-06-2008 |
20090046702 | SECONDARY SYNCHRONIZATION CODEBOOK FOR E-UTRAN - Providing for secondary synchronization encoding utilizing a primary synchronization channel (P-SCH)-related scrambling code is described herein. Scrambled secondary synchronization codes (SSCs) can be assigned to multiple base stations of a radio access network (RAN). By way of example, PSC-based scrambling codes can be created from a plurality of M-sequences generated from a common polynomial expression. Further, an SSC codebook is provided that selects sequence pairs of a sequence matrix for generating SSCs. Selection can be based on transmission characteristics of resulting SSCs, providing reduced interference in planned, semi-planned and/or unplanned mobile deployments. | 02-19-2009 |
20090122839 | SCRAMBLING CODES FOR SECONDARY SYNCHRONIZATION CODES IN WIRELESS COMMUNICATION SYSTEMS - Systems and methodologies are described that facilitate employing a scrambling code from a set of scrambling codes, which is indexed by primary synchronization codes (PSCs), to scramble or descramble a secondary synchronization code (SSC). The scrambling codes in the set can be designed to optimize peak-to-average power ratios and/or mitigate cross correlation. For example, the scrambling codes can be based on different M-sequences generated from disparate polynomials. In accordance with another example, the scrambling codes can be based on different cyclic shifts of the same M-sequence. According to another example, the scrambling codes can be based upon binary approximations of possible primary synchronization codes utilized in a wireless communication environment. Pursuant to a further example, the scrambling codes can be based on different Golay complementary sequences. | 05-14-2009 |
20110013531 | LOW REUSE PREAMBLE - Systems and methodologies are described that facilitate cell search and detection in high interference situations. Heterogeneous network can include a plurality of unplanned femtocell deployments, which can prevent macrocellular UEs from acquiring macrocells. A base station within the network can transmit a low reuse preamble that includes system information, wherein the low reuse preamble is tunneled on a downlink traffic channel such as a physical downlink shared channel. A UE can detect the low reuse preamble and evaluate the preamble to obtain the system information. | 01-20-2011 |
20110026421 | ADAPTIVE TRANSMISSIONS IN COORDINATED MULTIPLE POINT COMMUNICATIONS - Systems and methodologies are described that facilitate adaptively communicating data to wireless devices. An access point can precode a dedicated reference signal (DRS) for transmitting to a wireless device, and the wireless device can receive the precoded DRS. The wireless device can determine the precoder by estimating a channel of the DRS and can provide channel condition feedback to the access point. The access point can create data signals including a single or a burst of data transmissions according to the feedback and can precode the data signals using the same precoder. The wireless device can additionally decode the data signals using the precoder. Moreover, the access point can cycle through precoders according to a patterned, random, pseudo-random, and/or similar sequence. | 02-03-2011 |
20110026473 | DETERMINING CONTROL REGION PARAMETERS FOR MULTIPLE TRANSMISSION POINTS - Systems and methodologies are described that facilitate determining control region parameters related to a plurality of carriers and/or coordinated multiple point (CoMP) access points. Wireless devices can receive control region parameters related to the carriers or CoMP access points from a serving access point over control channel resources. Additionally or alternatively, wireless devices can assume all carriers or CoMP access points have substantially the same control region as indicated in a control format indicator channel from the serving access point or based on a configured value. | 02-03-2011 |
20110032838 | MITIGATION OF CRS MISALIGNMENT IN COORDINATED MULTIPOINT COMMUNICATIONS - Certain aspects of the present disclosure relate to a method for coordinated multipoint wireless communications. A technique for joint processing of misaligned reference signals in coordinated multipoint communications is provided. In one aspect, a cell may transmit an offsetting reference signal which, when processed by a receiving user equipment, at least partially cancels a first reference signal transmitted by the cell. | 02-10-2011 |
20110038329 | EFFICIENT CONTROL CHANNEL DECODING IN CoMP COMMUNICATIONS - Certain embodiments of the present disclosure propose two efficient designs for a control channel in a Coordinated Multi-Point (CoMP) system. The proposed designs enable a user equipment (UE) to transmit acknowledgement (ACK) and negative acknowledgement (NACK) signals to one or more access points (APs) upon receiving transmissions from them. | 02-17-2011 |
20110038330 | ROBUST DECODING OF CoMP TRANSMISSIONS - Techniques for transmitting data and resource signals (RS) are provided. According to certain aspects, an access point may determine RS resource locations related to one or more access points in a CoMP set transmitting a common reference signal (CRS), map data transmissions initially over resources other than those related to the RS resource locations, and map remaining data transmissions over resources related to the RS resource locations. According to certain aspects, a wireless device may receive a signal from access points in a coordinated multiple point (CoMP) communication set comprising a common reference signal (CRS) superimposed over data, determine CRS locations in the signal that correspond to the CRS, and decode data from the signal based at least in part on the determined CRS locations. | 02-17-2011 |
20110182252 | NETWORK-ASSISTED CELL ACCESS - Providing for access point assisted signal acquisition for heterogeneous access point wireless networks is described herein. By way of example, a closed subscriber group (CSG) base station, such as a home NodeB (HNB) can be configured to provide temporary, limited access to a UE that is not authorized to access the HNB. Upon receiving and rejecting an access probe, the HNB can negotiate with a surrounding macro network to provide service for the UE. Further, the HNB can forward signal acquisition data, to assist in proper decoding of pilot or synchronization signals of the macro network. In particular aspects, the HNB can reduce power or blank transmissions on reserved access resources to reduce interference for the UE. By these and other disclosed mechanisms, the HNB can assist a non-CSG subscriber to obtain network service, and mitigate interference effects due to proximity to the UE. | 07-28-2011 |
20110228883 | COMBINING DECISION METRICS FOR DECODING BASED ON PAYLOAD DIFFERENCE - Decision metrics used to decode wireless communication payloads are combined for successive frames to improve decoding of the later received frames. A bitwise payload difference between successive frames is encoded in the same manner the payloads are encoded. Decision metrics determined for the earlier received frame are combined with the encoded payload difference to generate adjusted decision metrics. The adjusted decision metrics are combined with decision metrics determined for the later received frame. The combined decision metrics are decoded to generate a payload for the later received frame. If the decoding is not successful the combined decision metrics are carried forward and the process is repeated based on the payload difference between the following frames. | 09-22-2011 |
20110249548 | EFFICIENT ZADOFF-CHU SEQUENCE GENERATION - Efficient apparatus and method for Zadoff-Chu (“Chu”) sequence generation avoids additional processing and hardware complexity of conventional quadratic generating formula followed by Discrete Fourier Transform (DFT) with a reference signal generator that produces both a Zadoff-Chu sequence and its DFT. In the wireless communication system (e.g., Long Term Evolution (LTE) system), Chu sequences are extensively used, especially in the uplink (UL). Because of the single carrier operating mode, transmitting a Chu sequence in principle involves a succession of generating that sequence, performing a DFT operation and then an IFFT operation. Assuming that the sequence length is N, the initial sequence generation requires 2N multiplications and the DFT requires more than N log 2(N) multiplications. Given the frequent processing of Chu sequences, this would represent a complexity burden. The invention makes it possible to perform the sequence generation and DFT steps without any multiplication operation, except for possibly calculating certain initial parameters. | 10-13-2011 |
20110255486 | METHODS AND APPARATUS FOR CROSS-CELL COORDINATION AND SIGNALING - Methods and apparatus for providing cross-cell signaling and/or coordination for interference mitigation in wireless communication networks are described. In one aspect, a UE associated with a serving eNB may receive control signaling from another non-serving eNB in a different cell. The control signaling may be consistent with a characteristic of the serving eNB and associated cell. In another aspect, multiple eNBs may coordinate transmission of DL resources to minimize collisions of control signaling resources. | 10-20-2011 |
20110261673 | MODIFIED SPATIAL DIVERSITY SCHEMES FOR COVERAGE ENHANCEMENT - In one aspect, a method to enhance coverage in a heterogeneous wireless network wireless communication is disclosed. The method includes generating a reference signal indicating a plurality of transmit antenna ports and generating modulation symbols. Modulation symbols are assigned to each of the plurality of transmit antenna ports, in accordance with a spatial diversity coding scheme for the plurality of transmit antenna ports. At least one of the modulation symbols assigned to at least one of the plurality of transmit antenna ports is muted prior to transmission in accordance with the spatial diversity coding scheme. The non-muted modulation symbols and the reference signal are transmitted on the other of the plurality of transmit antenna ports. | 10-27-2011 |
20110268230 | OPTIMIZING A RECEIVER FOR MULTIPLE ANTENNA CONFIGURATIONS - A method for optimizing a multiple input multiple output (MIMO) receiver for multiple antenna configurations is disclosed. A noise covariance is determined based on a noise estimate of a wireless signal. A Cholesky decomposition matrix is determined based on the noise covariance. A whitening matrix is determined based on the Cholesky decomposition matrix. The wireless signal is whitened using the whitening matrix. | 11-03-2011 |
20110274097 | DETECTING AND REPORTING PHYSICAL-LAYER CELL IDENTIFIER COLLISIONS IN WIRELESS NETWORKS - Physical-Layer Cell Identifier (PCID) collisions may occur in a wireless network when two neighboring evolved Node Bs (eNBs) having different Global Cell Identifiers (GCID) select identical PCIDs. Evolved Node Bs may uniquely identify themselves by transmitting on a broadcast channel, such as a Physical Broadcast Channel (PBCH), a pattern of bits corresponding to the eNB's GCID. Individual User Equipments (UEs) may recognize the PCID collision by decoding the PBCH payload to identify different GCID-modulated payloads from two eNBs involved in the PCID collision. Alternatively, UEs may detect PCID collisions in the wireless network by monitoring Primary Synchronization Signals (PSS) and Secondary Synchronization Signals (SSS) on the PBCH for identical signals separated by a relatively large time offset. After detecting a PCID collision, the UEs may attempt by best effort to report the PCID collision, may report to a fallback eNB, or the UEs may use special resources on an uplink channel. | 11-10-2011 |
20110280295 | RECURSIVE IMPLEMENTATION FOR CALCULATION OF WHITENING MATRIX - Certain aspects of the present disclosure relate to techniques for recursive implementation of whitening matrix calculation based on functional reuse as a part of wireless receiver in a Long Term Evolution (LTE) wireless system. | 11-17-2011 |
20110286376 | PER-CELL TIMING AND/OR FREQUENCY ACQUISITION AND THEIR USE ON CHANNEL ESTIMATION IN WIRELESS NETWORKS - A method, an apparatus, and a computer program product for wireless communication are provided in which a system timing is estimated, derived from timing of one or more cells, a timing offset is determined for a plurality of cells relative to the estimated system timing, and signals received form the plurality of cells are processed using the timing offsets. In addition, a method, an apparatus, and a computer program product for wireless communication are provided in which a carrier frequency is estimated, derived from a frequency of one or more cells, a frequency offset is determined for a plurality of cells relative to the estimated system timing, and signals received form the plurality of cells are processed using the frequency offsets. | 11-24-2011 |
20110292875 | APPARATUS AND METHOD FOR PHYSICAL BROADCAST CHANNEL (PBCH) DECODING FOR MULTIPLE CELLS - A method of wireless communication includes generating a list of cells for physical broadcast channel (PBCH) decoding. The method also includes allocating memory for decoding and cancelling a subset of cells from the generated cell list. The method further includes storing information related to subsets of cells from the generated list in the allocated memory during different time periods. The allocated memory is sufficient for attempting, at each time period, decoding of each subset of cells and cancelling of decoded cells in each subset. The method further includes cycling through the generated cell list by processing each subset of the cell list during the different time periods. | 12-01-2011 |
20110305237 | SECONDARY SYNCHRONIZATION CODEBOOK FOR E-UTRAN - Providing for secondary synchronization encoding utilizing a primary synchronization channel (P-SCH)-related scrambling code is described herein. Scrambled secondary synchronization codes (SSCs) can be assigned to multiple base stations of a radio access network (RAN). By way of example, PSC-based scrambling codes can be created from a plurality of M-sequences generated from a common polynomial expression. Further, an SSC codebook is provided that selects sequence pairs of a sequence matrix for generating SSCs. Selection can be based on transmission characteristics of resulting SSCs, providing reduced interference in planned, semi-planned and/or unplanned mobile deployments. | 12-15-2011 |
20120008516 | TTL OPERATIONS FOR SMALL RB ASSIGNMENTS - Certain aspects of the present disclosure provide techniques for wireless communications, wherein more accurate timing offset calculations may be achieved for uplink transmissions with a relatively small number of assigned resources. | 01-12-2012 |
20120044928 | DETERMINATION OF NETWORK SYNCHRONIZATION - User equipment (UE) associated with synchronous networks operate in a synchronous mode while UEs associated with asynchronous networks operate in an asynchronous mode. When operating in a synchronous mode, a UE can significantly improve performance of synchronization signal detection, data decoding, and tracking loop management by using the interference cancellation (IC) techniques that are not available in an asynchronous mode of operation. Obtaining synchronization indicators and determining the synchronization status of the current network by UE is disclosed. The determination may be based on the synchronization indicator, whether detected through signal detection, signal measurements, signal analysis, or the like. | 02-23-2012 |
20120046056 | SAMPLE SELECTION FOR SECONDARY SYNCHRONIZATION SIGNAL (SSS) DETECTION - Methods and apparatus for selecting samples for secondary synchronization signal (SSS) detection are described. Several alternatives are provided for efficient cell identifier detection. In a first alternative, multiple bursts of a signal received from a cell are sampled with non-uniform spacing between sampling intervals to determine a sequence for cell identification. In a second alternative, samples of a first and a second signal received from a stronger cell are cancelled, and a sequence for detecting a weaker cell is determined by reducing effects of the samples of a third signal received from the weaker cell which do not overlap with the primary synchronization signal (PSS) or SSS of the stronger cell. In a third alternative, a sequence for detecting a weaker cell is determined by reducing effects of any sampled bursts that correspond to a high transmission power portion of a signal from a stronger cell. | 02-23-2012 |
20120263247 | METHOD AND APPARATUS FOR SELECTING REFERENCE SIGNAL TONES FOR DECODING A CHANNEL - Methods and apparatuses are provided that include selecting reference signal (RS) or other tones to utilize in estimating a channel for decoding one or more channels. Where the RS tones are interfered by other base stations, interference cancelation can be performed over the RS tones. Since interference can vary over the tones, interference cancelation can yield RS tones of varying quality. Thus, a quality of each of the RS tones can be determined, and at least a subset of the RS tones can be selected for estimating a channel. Additionally or alternatively, the RS tones can be weighted or otherwise classified for performing channel estimation using the RS tones. | 10-18-2012 |
20130095829 | IDLE MODE OPERATION IN HETEROGENEOUS NETWORKS - An idle mode UE can RACH to a cell different from the cell paging the UE. The UE can be allocated additional time to respond to all cells in the neighborhood to identify the cell in which to RACH. Interference cancellation can occur at different rates based on whether the UE is in connected mode or idle mode. The time to respond to the page can be a function of a paging cycle. Additionally, a variable bias may promote early handoff to lower power cells and late handoff to high power cells. | 04-18-2013 |
20130128792 | NETWORK-ASSISTED CELL ACCESS - Providing for access point assisted signal acquisition for heterogeneous access point wireless networks is described herein. By way of example, a closed subscriber group (CSG) base station, such as a home NodeB (HNB) can be configured to provide temporary, limited access to a UE that is not authorized to access the HNB. Upon receiving and rejecting an access probe, the HNB can negotiate with a surrounding macro network to provide service for the UE. Further, the HNB can forward signal acquisition data, to assist in proper decoding of pilot or synchronization signals of the macro network. In particular aspects, the HNB can reduce power or blank transmissions on reserved access resources to reduce interference for the UE. By these and other disclosed mechanisms, the HNB can assist a non-CSG subscriber to obtain network service, and mitigate interference effects due to proximity to the UE. | 05-23-2013 |
20130231123 | PER-CELL TIMING AND/OR FREQUENCY ACQUISITION AND THEIR USE ON CHANNEL ESTIMATION IN WIRELESS NETWORKS - A method, an apparatus, and a computer program product for wireless communication are provided in which a system timing is estimated, derived from timing of one or more cells, a timing offset is determined for a plurality of cells relative to the estimated system timing, and signals received form the plurality of cells are processed using the timing offsets. In addition, a method, an apparatus, and a computer program product for wireless communication are provided in which a carrier frequency is estimated, derived from a frequency of one or more cells, a frequency offset is determined for a plurality of cells relative to the estimated system timing, and signals received form the plurality of cells are processed using the frequency offsets. | 09-05-2013 |
20140161043 | SAMPLE SELECTION FOR SECONDARY SYNCHRONIZATION SIGNAL (SSS) DETECTION - Methods and apparatus for selecting samples for secondary synchronization signal (SSS) detection are described. Several alternatives are provided for efficient cell identifier detection. In a first alternative, multiple bursts of a signal received from a cell are sampled with non-uniform spacing between sampling intervals to determine a sequence for cell identification. In a second alternative, samples of a first and a second signal received from a stronger cell are cancelled, and a sequence for detecting a weaker cell is determined by reducing effects of the samples of a third signal received from the weaker cell which do not overlap with the primary synchronization signal (PSS) or SSS of the stronger cell. In a third alternative, a sequence for detecting a weaker cell is determined by reducing effects of any sampled bursts that correspond to a high transmission power portion of a signal from a stronger cell. | 06-12-2014 |
20140161044 | SAMPLE SELECTION FOR SECONDARY SYNCHRONIZATION SIGNAL (SSS) DETECTION - Methods and apparatus for selecting samples for secondary synchronization signal (SSS) detection are described. Several alternatives are provided for efficient cell identifier detection. In a first alternative, multiple bursts of a signal received from a cell are sampled with non-uniform spacing between sampling intervals to determine a sequence for cell identification. In a second alternative, samples of a first and a second signal received from a stronger cell are cancelled, and a sequence for detecting a weaker cell is determined by reducing effects of the samples of a third signal received from the weaker cell which do not overlap with the primary synchronization signal (PSS) or SSS of the stronger cell. In a third alternative, a sequence for detecting a weaker cell is determined by reducing effects of any sampled bursts that correspond to a high transmission power portion of a signal from a stronger cell. | 06-12-2014 |
20150049672 | METHODS AND APPARATUS FOR AVOIDING OR ESCAPING CELL RANGE EXPANSION (CRE) IN A HETEROGENEOUS NETWORK - Certain aspects relate to methods and apparatus for avoiding and/or escaping cell range expansion (CRE) in a heterogeneous network (HetNet). A user equipment (UE) may detect the occurrence of one or more conditions while the UE is in a region of cell range expansion (CRE) in which the UE may be handed over from a first cell of a first power class type to a second cell of a second power class type, the second power class type being lower than the first power class type. The UE may take action to stop being served by the second cell or avoid being handed over to the second cell in response to the detection. | 02-19-2015 |
20150071387 | BLIND CRS DETECTION - Certain aspects of the present disclosure relate to methods and apparatus for blind detection of cell-specific reference signals. Methods and apparatus are provided for detecting a cell-specific reference signal (CRS) in an orthogonal frequency division multiplexed (OFDM) symbol by a user equipment (UE). The method generally includes predicting a current channel response of a current OFDM symbol based on a channel response of at least one previous OFDM symbol, estimating a noise power level of the current OFDM symbol, forming a log likelihood ratio (LLR) of two detection hypotheses based on the predicted current channel response and the estimated noise power level, comparing the LLR to a pre-determined threshold, and determining that at least one CRS is present in the current OFDM symbol based on the comparison. | 03-12-2015 |