Abstract:
Techniques for mitigating interference in a wireless communication system are described. In an aspect, pertinent transmission parameters for a served UE may be sent to at least one interfered UE to support interference mitigation. In one design, information for at least one transmission parameter for a data transmission sent by a first cell to a first UE may be transmitted to at least one UE served by a second cell to enable the at least one UE to perform interference mitigation for the data transmission sent by the first cell to the first UE. The information may be transmitted by either the first cell or the second cell. In another aspect, a cell may send transmission parameters for a UE via a pilot. In yet another aspect, scrambling may be performed by a cell at symbol level to enable an interfered UE to distinguish between modulation symbols of desired and interfering transmissions.
Abstract:
A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus determines a first decoding candidate in a first search space and a second decoding candidate in a second search space, where the first decoding candidate and the second decoding candidate have a same size but different definitions of information fields, identifies a difference in the information fields, and determines one of the first decoding candidate and the second decoding candidate as a valid candidate based on the identified difference. The apparatus further generates first control information for transmitting in a first search space, codes the first control information, wherein the code applied to the first control information is specific to the first search space and different from code applied to second control information in a second search space, and transmits the coded first control information in the first search space.
Abstract:
A method, an apparatus, and a computer program product for wireless communication are provided in which signals are received from a first base station and a second base station, and a measurement is made of synchronization parameters between the first and second base stations at a user equipment. A signal is transmitted from the user equipment to at least one of the first or second base stations with information about the synchronization parameters. The synchronization parameters generally inform the first and/or second base stations of an adjustment to make to subsequent signals to align reception of the subsequent signals in at least one of time or frequency domains. The user equipment receives a third signal from the first base station and a fourth signal from the second base station, the third and fourth signals being substantially aligned in at least one of the time or frequency domains.
Abstract:
Techniques for mitigating pilot pollution in a wireless network are described. In an aspect, pilot pollution may be mitigated by reducing density and/or transmit power of common pilots whenever possible. A cell may send a common pilot at a first density and a first transmit power level during a first time period and may send the common pilot at a second density and a second transmit power level during a second time period. The second density may be lower than the first density and/or the second transmit power level may be lower than the first transmit power level. Lower density may be achieved by sending the common pilot less frequently, on fewer subcarriers, and/or from fewer antennas. The cell may determine whether to reduce the density and/or transmit power of the common pilot based on network loading, SINRs of terminals, etc. In another aspect, pilot pollution may be mitigated by performing pilot cancellation at a terminal.
Abstract:
Systems and methodologies are described that facilitate dynamically forming clusters in a wireless communication environment. A set of non-overlapping clusters can be formed dynamically over time and in a distributed manner. Each of the clusters can include a set of base stations and a set of mobile devices. The clusters can be yielded based upon a set of local strategies selected by base stations across the network converged upon through message passing. For example, each base station can select a particular local strategy as a function of time based upon network-wide utility estimates respectively conditioned upon implementation of the particular local strategy and disparate possible local strategies that can cover the corresponding base station. Moreover, operation within each of the clusters can be coordinated.
Abstract:
Systems and methodologies are described that facilitate cooperation strategy selection for a network multiple-in-multiple-out (N-MIMO) communication system. As described herein, one or more nodes in a communication system capable of N-MIMO communication can calculate marginal utilities, projected per-user rates, and/or other parameters corresponding to respective associated users. Based on these calculations, respective network nodes can perform user scheduling and selection, cell scheduling and selection, selection of a cooperation strategy (e.g., coordinated silencing, joint transmission, coordinated beamforming, etc.), and/or other operations to provide cooperative communication for respective users. As further described herein, projected rate calculation for a given user can be adjusted based on processing or channel implementation loss associated with the user, interference nulling capability of the user, or other factors. As additionally described herein, these and/or other parameters can be fed back by respective users to a serving network node and/or mandated via system performance requirements.
Abstract:
Techniques for mitigating interference in a wireless communication system are described. In an aspect, pertinent transmission parameters for a served UE may be sent to at least one interfered UE to support interference mitigation. In one design, information for at least one transmission parameter for a data transmission sent by a first cell to a first UE may be transmitted to at least one UE served by a second cell to enable the at least one UE to perform interference mitigation for the data transmission sent by the first cell to the first UE. The information may be transmitted by either the first cell or the second cell. In another aspect, a cell may send transmission parameters for a UE via a pilot. In yet another aspect, scrambling may be performed by a cell at symbol level to enable an interfered UE to distinguish between modulation symbols of desired and interfering transmissions.
Abstract:
Techniques for communicating on multiple carriers in a wireless communication network are described. In an aspect, different transmit power levels may be used for different carriers to mitigate interference. A first base station may be assigned one or more carriers among multiple carriers available for communication. A second base station may be assigned one or more carriers not assigned to the first base station. Each base station may communicate on each assigned carrier at a first (e.g., full) transmit power level and may communicate on each unassigned carrier at a second (e.g., lower) transmit power level lower. The first and second base stations may belong in different power classes or support different association types. In another aspect, control information may be sent on a designated carrier to support communication on multiple carriers. In yet another aspect, a base station may broadcast bar information indicating the status of carriers.
Abstract:
Systems and methodologies are described herein that facilitate the generation and use of separable, hierarchical channel state feedback in a wireless communication system. As described herein, in the event that multiple network nodes cooperate to conduct downlink transmissions to a network user, channel state feedback as reported by the network user can be separated into intra-node feedback relating to per-node channel conditions and inter-node feedback relating to relative phase and/or amplitude between channels corresponding to respective nodes. Further, a network user can select to report intra-node feedback and/or inter-node feedback based on network instructions, a cooperation strategy to be utilized by respective network nodes, or the like. As additionally described herein, respective codebooks on which inter-node and intra-node channel feedback is based can be configured to convey information relating to a partial channel description and/or to vary based on resource units (e.g., sub-bands, resource blocks, etc.) utilized for downlink communication.
Abstract:
Systems and methodologies are described herein that facilitate interference measurement and reporting in a network multiple-in-multiple-out (N-MIMO) communication system. As described herein, a network device can measure and report interference corresponding to network nodes outside a designated set of nodes that can cooperatively serve the device. Respective interference reports can additionally identify dominant interfering nodes, correlation between transmit antennas of respective nodes, or the like. Subsequently, respective interference reports can be combined with per-node channel information to manage coordination and scheduling across respective network nodes. As further described herein, interference from a network node can be measured by observing reference and/or synchronization signals from the network node. To aid such observation, respective non-interfering network nodes can define null pilot intervals in which transmission is silenced or otherwise reduced. As additionally described herein, loading information broadcasted by respective interfering network nodes can be identified and utilized in connection with interference calculation.