Abstract: Smaller patterns of regularly-spaced pilot symbols are discerned from a larger pattern of irregularly-spaced pilot symbols transmitted in the time-frequency domain. Accordingly, the irregularly-spaced pilot symbols can be partitioned into at least two different groups of regularly-spaced pilot symbols in the time-frequency domain. Each group of regularly-spaced pilot symbols is individually processed with lower complexity and the results combined to generate an accurate time-frequency channel response estimate. According to an embodiment, a set of irregularly-spaced pilot symbols is transmitted over a time-frequency window. Channel response is estimated based on the pilot symbols by grouping the pilot symbols into subsets of regularly-spaced pilot symbols. An intermediate quantity is generated for each subset of regularly-spaced pilot symbols as a function of the pilot symbols included in the subset. The channel response is estimated over the time-frequency window as a function of the intermediate quantities.

Abstract: Transmitted signals are modified to facilitate the emulation of circular convolution in non-contiguous transmission environments. These modified signals may be derived from well-known signature sequences. In an exemplary method, a tail portion of a final segment of a base signal is prefixed to an initial segment of the base signal, to form a first transmit segment. One or more additional transmit segments are formed by prefixing, to each of the one or more segments of the base signal other than the initial segment, a tail portion of the immediately preceding segment of the base signal. The transmit segments so formed are transmitted in respective ones of the plurality of non-contiguous transmit-time intervals. Corresponding methods for receiving the transmitted segments and reconstructing the base signal are also described, as are corresponding transmitting and receiving apparatuses.

Abstract: The inventive methods and apparatus disclosed herein allocate and assign uplink reference signals to cells (104, 106) within a cell cluster (100, 302, 402, 502) based on the type of cell. According to an embodiment, uplink reference signals are allocated within a cell cluster (100, 102, 302, 402, 502) by partitioning a set of uplink reference signals allocated to the cell cluster (100, 102, 302, 402, 502) into mutually exclusive subsets of uplink reference signals. One of the subsets is allocated to each of the border cells (104) and the entire set of uplink reference signals is allocated to the interior cells (106). Accordingly, more uplink reference signals are available for assignment to mobile devices (310, 410, 510) served by the interior cells (106) than by the border cells (104).

Abstract: A large scale, self-calibrating multi-antenna wireless communication system calibrates the transmit-receive RF chains of antennas in the system. The system, during a first time interval, transmits a pilot signal from at least those antennas in a first time-reuse group, so that the pilot signals are received at antennas in one or more other time-reuse groups. The system, during a second time interval, transmits a pilot signal from at least those antennas in a second time-reuse group, so that the pilot signals are received at antennas in one or more other time-reuse groups. The system also, during a third time interval, transmits a pilot signal from at least those antennas in a third time-reuse group, so that the pilot signals are received at antennas in one or more other time-reuse groups. Based on these received pilot signals, the system calculates RF-chain calibration factors for one or more of the antennas.

Abstract: A Coordinated Multipoint (CoMP) controller advantageously reduces the transmit powers of transmissions coordinated across a plurality of sub-cells within a CoMP cell. The CoMP controller determines serving sub-cell path gains and interfering sub-cell path gains for a set of mobile terminals to be served by distinct sub-cells. The CoMP controller then evaluates an objective function that expresses an aggregate throughput of concurrent transmissions to be sent to or received from the set of mobile terminals as a function of the serving sub-cell path gains, the interfering sub-cell path gains, and the individual transmit powers of those transmissions, to determine the combination of individual transmit powers that maximizes the aggregate throughput while meeting minimum quality of service requirements for the mobile terminals. The combination of individual transmit powers will necessarily require less power than if the concurrent transmissions were each sent at maximum transmit power.

Abstract: A method of synchronizing signals in a wireless network uses a two part preamble transmitted on the downlink between a base station and a mobile station. The preamble includes a common pilot common to a plurality of base stations and a dedicated pilot unique to the transmitting base station. The mobile station performs coarse synchronization based on the common pilot and fine synchronization based on the dedicated pilot. The mobile station also identifies one or more nearby cells based on unique pilot tones in the dedicated pilot transmitted by the nearby cells.

Abstract: One or more embodiments taught herein provide a hybrid access arrangement using a contention-based channel and a scheduled channel on a communication link. As a point of significant efficiency, given users transmit autonomously on the contention-based channel, without need for scheduling overhead. However, if a contention overload occurs on the contention-based channel, the involved users are identified from unique signature sequences included in their user transmissions. The identified users are temporarily managed as scheduled users on the scheduled channel, which supplements the contention-based channel and therefore may use limited communication link resources in comparison to the contention-based channel. Users not involved in the contention overload generally continue operating on the contention-based channel.

Abstract: A wireless communication device uses a time-invariant delay-Doppler channel response estimate for received signal demodulation. The device provides coherent signal demodulation by accounting for frequency and time selectivity in a land-based mobile communication environment, which arise mainly because of delay and Doppler shifts, respectively. In one embodiment, the wireless communication device includes a channel estimator that estimates channel response in a wireless communication network by estimating a delay-Doppler response of a wireless communication channel to obtain a delay-Doppler channel response estimate and converting the delay-Doppler channel response estimate to a time-varying channel response estimate, e.g., a time-varying frequency or impulse response. The delay-Doppler response may be estimated in a continuous or discrete domain.

Abstract: According to methods and apparatus taught herein, an Orthogonal Frequency Division Multiplexed (OFDM) transmitter increases pilot density in the edge regions of an OFDM signal, such as by using additional pilot sub carriers in the edge regions. For example, the OFDM signal includes first pilot sub carriers uniformly distributed across the frequency band of the OFDM signal, and second pilot sub carriers distributed within the edge regions. A corresponding OFDM receiver circuit uses the increased pilot density to improve channel estimation. For example, the receiver circuit uses the first pilot sub carriers in a Maximum Likelihood (ML) estimation process to obtain first channel estimates, and uses the results of ML estimation along with the second pilot sub carriers in a Minimum Mean Square Error (MMSE) estimation process to obtain second channel estimates. The receiver forms the improved channel estimates using the first and second channel estimates.

Abstract: A method and apparatus for channel estimation based on extracting channel information, including noise spectral density, from a received signal, and advantageously exploiting that information for improved channel estimation accuracy. One embodiment is directed to a method of generating channel estimates in a wireless communication receiver, for processing a received communication signal. The method includes generating first channel estimates from a set of pilot observations obtained from the received communication signal, using a first channel estimation process that is not dependent on knowledge of channel statistics. The method further includes estimating channel statistics and a noise variance from the first channel estimates, and generating second channel estimates from the set of pilot observations, the estimated channel statistics, and the estimated noise variance, using a second channel estimation process that is dependent on knowledge of the channel statistics.

Abstract: Network-wide inter-cell interference is reduced by aggregating cells (herein, sub-cells) into Coordinated MultiPoint (CoMP) cells, each having a controller. The CoMP cells are divided into sets, similar to a frequency reuse plan. Scheduling information regarding transmissions scheduled to and from UEs in one set of CoMP cells is transmitted to controllers in sets of neighboring CoMP cells, in advance of the transmissions. Controllers in the receiving sets of CoMP cells schedule transmission to minimize both inter-sub-cell interference and interference with the set of CoMP cells that transmitted the scheduling information, and assuming no interference from other CoMP cells. They then transmit scheduling information to subsequent set(s) of CoMP cells. The order of scheduling information transmission between sets of CoMP cells may be rotated for fairness.

Abstract: According to one embodiment, a wireless communication device estimates channel response based on a reduced-density common pilot signal comprising a plurality of regularly spaced common pilot symbols when the reduced-density common pilot signal is sufficient for estimating the channel response with a desired accuracy. The wireless communication device estimates the channel response based on the reduced-density common pilot signal and one or more additional pilot symbols adaptively allocated to the wireless communication device when the reduced-density common pilot signal is insufficient for estimating the channel response with the desired accuracy.

Abstract: Inter-CoMP cell interference is reduced by “extending” at least one CoMP cell to include UEs served by a neighboring CoMP cell in the extended CoMP cell's transmission calculations, so as to minimize interference to the UEs served by other CoMP cells. Each UE in a border sub-cell identifies neighboring CoMP cells from which it receives interference in excess of a threshold value, and includes the interfering CoMP cells in a close-neighbor set. The close-neighbor set is transmitted to the UE's serving CoMP cell controller. When downlink transmissions are scheduled to the target UE, the controller notifies the neighboring CoMP cells in the close-neighbor set, identifying the target UE. Those CoMP cells then use information about the channel conditions from their transmit antennas to the target UE receive antennas to compute transmissions to UEs they serve, with the constraint that interference to the target UE is below a predetermined level.

Abstract: At least some reference symbols dedicated to a particular communication device are transmitted in resource blocks allocated to other devices. This way, reference symbol assignments are not unduly restricted by other constraints placed on the boundary elements of a resource block. According to an embodiment, data and reference signals are transmitted by transmitting a resource block allocated to a first communication device. The resource block includes a plurality of resource elements, each resource element corresponding to a modulation symbol. At least one reference symbol associated with the resource block and dedicated to the first communication device is transmitted in a resource block allocated to a second communication device. On the receive side, the communication device can perform channel estimation based on reference symbols dedicated to the device that are transmitted in resource blocks allocated to the device and in resource block(s) allocated to other communication device(s).

Abstract: A system, method and node of implementing interference suppression for estimation of a signal parameter of a base station transmission at a User Equipment (UE) in a telecommunications network with irregular reference signal patterns assigned to base stations. A list of base stations for which a parameter of the transmitted signal is to be estimated and a list of OFDM symbols and subcarriers to avoid for each base station are compiled. The compiled list is sent to the UE, which performs measurements for each base station using the received measurement information and simple interference avoidance is performed utilizing OFDM symbols and subcarriers not on the list of OFDM symbols and subcarriers to avoid. The measurements are then sent to the network.

Abstract: A method and Coordinated Multi-Point (CoMP) cell controller for reducing interference in a wireless communication network in which a first CoMP cell neighbors a second CoMP cell. The CoMP cell controller in the first CoMP cell gathers scheduling information from border sub-cells in the neighboring second CoMP cell in which transmissions to and from UEs cause inter-CoMP cell interference in at least one sub-cell in the first CoMP cell. The CoMP cell controller augments intra-CoMP cell scheduling information in the first CoMP cell with the scheduling information from the border sub-cells to create augmented scheduling information. The CoMP cell controller then utilizes the augmented scheduling information to schedule transmissions to and from UEs within the at least one sub-cell in the first CoMP cell to reduce the inter-CoMP cell interference.

Abstract: A wireless communication network employs a distributed antenna system to provide radio coverage. The wireless communication network comprises a plurality of access points providing service in respective coverage areas. The access point within each coverage area connects to a plurality of antennas that are widely distributed within the coverage area. Radio resources at antennas within the overlapping region of two or more neighboring coverage areas are shared by the access points in the neighboring coverage areas according to a multiple access scheme. The sharing of radio resources within the overlapping region of two or more coverage areas allows the overlapping region to be enlarged, thereby providing more time to complete a handover.

Abstract: A method and controller for reducing inter-cell interference within a Coordinated Multi-Point (CoMP) cellular network architecture. Multiple CoMP cells in the network architecture are grouped into a number of mutually exclusive subsets. The CoMP cells in each subset are sufficiently separated from each other geographically so that no inter-cell interference occurs among them, and thus they can be scheduled independently. Each subset then takes turn scheduling in a certain order. As each subset schedules its transmissions, it avoids causing interference to subsets that have already scheduled, and then passes sufficient information to the remaining subsets so that the same interference avoidance measures can be taken. The scheduling and passing of the information is preferably performed before the data transmission phase, which occurs once every Transmission Time Interval (TTI).

Abstract: The present invention relates to a method for detecting a pilot pattern, comprising a pilot signal sp(t), in a received signal r(t) implemented in an Orthogonal Frequency Division Multiplexing (OFDM) system. The method comprises the steps: computing a value of a log-likelihood function (?0,?0) for a hypotheses space specified by the pilot signal sp(t) and an initial time frequency offset (?0,?0), and relating the computed value to a reference value to detect the pilot pattern.

Abstract: Multipoint wireless communications are coordinated in cells with radiation that is emanated from antennas in an inward direction. In an example embodiment, an apparatus includes a first antenna, a second antenna, a third antenna and a controller. The first antenna emanates radiation from a first location in an inwardly direction for a cell. The second antenna emanates radiation from a second location in an inwardly direction for the cell. The third antenna emanates radiation from a third location in an inwardly direction for the cell. The controller coordinates the emanation of the radiation via the first, second, and third antennas so as to reduce intra-cell interference for remote terminals located within the cell. The coordination may be effected in accordance with one or more coordinated multi-point (transmission/reception) (CoMP) techniques. Different numbers of sub-cells and antennas per cell and different CoMP cell organizations may be implemented.