192results about How to "Reduce Inter-Cell Interference" patented technology

A novel and useful method and system for resource allocation in OFDM communication systems. The mechanism reduces inter-cell interference by randomizing the inter-cell interference experienced in each cell. The mechanism effectively spreads the resource allocation in each cell in a random manner resulting in statistical-like inter-cell interference behavior. In many cases, use of the mechanism is sufficient to obviate the need for frequency planning between cells. A formula or hardware permutation machine is used to generate a random list of indices. The indices are then used to assign user data to the system resources. One or more parameters defining the random index generator at the transmitter are forwarded to the receiver to enable the local generation of an exact copy of the list of indices generated at the transmitter, thus enabling the DL and UL at the receiver while minimizing the required control channel signaling.

A method for deploying a cellular wireless communication network is provided. The method consists of: providing one or more micro base stations; autonomously deploying the micro base stations using a network access point linked to a cellular wireless communication network; and enabling configuration of the micro base stations to execute network operation commands from a network controller associated with the wireless communication network. Another aspect consists of enabling cooperation and network connectivity between micro base stations and other base stations, including micro base stations and large network base stations. Network connectivity to one or more cellular communication terminals associated with individuals or businesses subscribing to the cellular wireless communication network is enabled. A wireless network is also provided which is configurable to link a cellular wireless network through a high data transmission connection so as to define at least one access point between the micro base station and the wireless network. The network includes a wireless interface and receives operation commands from a network controller for configuration of micro base stations, to support the linking of cellular wireless terminals to the wireless network via the wireless interface by operation of the micro base station, as an intermediary. A corresponding system and computer readable medium is also provided

A method and an apparatus are provided for guaranteeing terminal mobility in a time division visible light communication system. In resource assignment in a position where the visible light communication terminal changes a cell, the terminal is assigned a resource to be used in a next cell in a cell boundary area from a communication coordinator, thereby guaranteeing the continuous mobility. The visible light communication system informs the terminal of cell boundary notice information for easily informing the terminal of the cell definition so that the terminal can recognize that the terminal is currently located in the cell boundary and is necessary to change the resource.

A method of efficiently transmitting CoMP feedback information from an user equipment, which performs CoMP operation, in a wireless communication system to reduce inter-cell interference is disclosed. The user equipment requests a neighboring cell, which affects the user equipment through interference, to restrict use of a specific beam pattern group in a serving cell direction. In this case, whether the user equipment will request such restriction is determined based on a channel status value of the user equipment. If the user equipment determines to request such restriction, the user equipment transmits a request message to a serving base station, the request message requesting to restrict use of the specific beam pattern group. In this case, the user equipment performs scheduling and requests a specific neighboring cell to restrict use of the specific beam pattern group at a specific resource region.

A few high power tones used for synchronization and / or other purposes are transmitted in a FDM system during a period of time, e.g., a symbol transmission time period. During normal data transmission symbol periods signals are transmitted using at least 10 tones, e.g., per symbol time. Less than 5 high power signals are transmitted in a symbol time with at least 80% the maximum total transmitter power transmitted being allocated to the high power signals where the maximum total transmitter power is determined from a period of time which may includes one or more data and / or high power tone transmission periods. When the high power tones are transmitted at most 20% of transmitter power is available for transmitting other tones with the power normally being distributed among multiple tones. Normally some tones which would be transmitted in a symbol time go unused during transmission of the high power signals.

Resources are assigned in units of resource blocks each composed of one or more subcarriers, inter-cell interference adjustment control information is notified to each other among base stations, a transmit power limitation on each of the resource blocks in a cell is decided based on the inter-cell interference adjustment control information; and the decision of the transmit power limitation is changed sequentially beginning at a resource block having a transmit power limitation different from the transmit power limitation on an adjacent resource block.

Disclosed is a method for transmitting a reference signal, in a method for transmitting a Channel State Information-Reference Reference Signal (CSI-RS) for measuring a transmission channel according to each antenna and a data signal in a broadband wireless communication system based on a MIMO scheme through a plurality of antennas.

A resource division, allocation, and transmitting / receiving method of downlink for reducing inter-cell interference in an orthogonal frequency division multiplexing system are provided. Entire downlink radio resources are divided into a traffic resource group for a traffic channel and a control resource group for a control channel, the traffic resource group is divided into a first traffic resource group for the intra-cell mobile terminals and a second traffic resource group for a cell-boundary mobile terminal, and a part of the first traffic resource group is imaginarily divided into a (1−1)-th preliminary traffic resource group, the (1−1)-th preliminary traffic resource group being a preliminary resource group for the cell-boundary mobile terminal. The control resource group is allocated to a control channel for the intra-cell mobile terminal; and a resource of the first traffic resource group or the second traffic resource group is allocated to a traffic channel for the mobile terminal according to inter-cell interference affected to the mobile terminal. Radio resources may be reused in each downlink cell of the OFDM system, the traffic may be rapidly transmitted to the cell boundary mobile terminal, a system capacity may be increased, the cell plane may be easily performed, and the system capacity may not be decreased although the mobile terminal number, locations, and traffic density is not uniform.

The invention relates to reducing interference in indoor cells in a wireless cellular communication network. Outdoor and indoor base stations operate at a common uplink carrier frequency. The indoor base station monitors an uplink inter-cell interference level, and, responsive to the uplink inter-cell interference level reaching a predetermined threshold level, synchronizes with an uplink transmission signal received from at least one potentially interfering user equipment which is connected to the outdoor base station but outside the downlink coverage area of the indoor base station. The interfering user equipment is commanded, via a downlink control channel of the outdoor base station, to lower the transmission power of the uplink transmission signal, and to thereby decrease the uplink inter-cell interference level on indoor base station.

A method and apparatus of mitigating inter-cell interference in a wireless communication system are provided. A user equipment receives serving-cell data over a first data channel indicated by a first control channel for which decoding is successful by monitoring a plurality of candidate control channels in a search space of a serving cell. The user equipment receives interfering-cell data over a second data channel indicated by a second control channel for which decoding is successful by monitoring a plurality of candidate control channels in a search space of an interfering cell. The A user equipment cancels interference from the interfering cell by processing the serving-cell data and the interfering-cell data.

A method for generating / transmitting a transmission-unit symbol sequence is disclosed. In the case of transmission information, the information is modulated in time and frequency domains on the basis of a predetermined transmission unit (e.g., a transmission time interval TTI or slot), simultaneous transmission of the information is made, and then a transmission unit symbol is generated / transmitted. A transmission sequence is masked in each symbol contained in one transmission unit. Symbol-unit circular shift (cyclic shift) is applied to the masked result, so that transmission efficiency increases. A control signal transmission method for supporting a variety of formats and a signal transmission method based on a prime-length sequence are also provided.

A cellular communication system comprising a plurality of user equipment and a network infrastructure. Radio resource of the plurality of cells is divided into more than one radio resource groups. A network infrastructure element detects a requirement of radio resource allocation for a user equipment and determines effective interference to be generated by the required radio resource to a defined group of neighbouring cells. User equipment is allocated a radio resource from one of the radio resource groups on the basis of the determined effective interference to be generated to the defined group of neighbouring cells. Inter-cell interference decreases and the throughput of the cellular system increases, but the exchange of physical layer information is not increased.

A method and apparatus for controlling inter-cell interference of control channels of hierarchical cells in a hierarchical cellular system based on Orthogonal Frequency Division Multiplexing (OFDM) are provided. The inter-cell interference control method of a base station in a hierarchical cellular system based on Orthogonal Frequency Division Multiplexing (OFDM) includes transmitting a broadcast channel, including information on an available bandwidth that is a part of an entire bandwidth, to a terminal, transmitting a control channel including data channel allocation information for the entire bandwidth to the terminal, and transmitting a data channel, as informed by the data channel allocation information, to the terminal. The inter-cell interference control method and apparatus support cooperative transmission of hierarchical cells while maintaining both backward compatibility and forward compatibility.

The present invention provides methods and devices for mitigating inter-cell interference in communication environments having a plurality of cells. In some embodiments, a time-frequency transmission resource that includes multiple sub-carriers over multiple OFDM symbol intervals is partitioned into a first zone and a second zone. In the first zone, transmissions are transmitted on at least one frequency sub-band which is common to all of the plurality of cells. In the second zone, transmissions are transmitted on at least one frequency sub-band which is used by less than all of the plurality of cells, so as to mitigate inter-cell interference. In some embodiments, in the first zone transmissions are transmitted using a transmission power which is common to all of the plurality of cells and in the second zone transmissions are transmitted using a transmission power which is used by less than all of the plurality of cells so as to mitigate inter-cell interference.

It is provided a wireless communication system comprising base stations that communicate with a terminal. Each of the base station has antennas. Each of the base stations transmits a first reference signal unique to each of the antennas which does not overlap with another antenna among the base stations at least in a vicinity thereof. The terminal receives the first reference signal and estimates a received power of the first reference signal for each of the antennas, selects antennas suitable for communication from among the antennas based on a result of estimating the received power, and transmits a result of selecting the antennas to the each of the base stations. The each of the base stations refers the result of selecting the antennas transmitted from the terminal, assigns the selected antennas belonging to different cells to the terminal, and notifies the terminal of a result of assigning the antennas.

Random beams and FFR are used in combination, frequencies are grouped into a zone associated with the center of a cell and a zone associated with the border of the cell, and the random beams are applied only to the zone associated with the border of the cell. Since the number of resources to be allocated to the random beams decreases, a terminal lying on the border of the cell can reduce overhead. Using the zone associated with the center of the cell, beam scheduling can be freely performed within the cell.

A FFR (fractional frequency reuse)-based network MIMO (multiple-input multiple-output) transmission architecture in a cellular system that employs cell sectoring using directional antennas. Each cell is sectorized into three outer sectors using three directional antennas which transmit in three different directions using three different frequency subbands. The cell sectors are arranged based on a frequency partition scheme so that three sectors in three neighboring cells form a coordinated group for network MIMO transmission. A regular and a rearranged frequency partition are described. Further, a practical implementation of SON (self organizing network)-based three-cell FFR-based network MIMO for a wireless OFDM system is described. In this implementation, a server connected to multiple base stations (BSs) defines multiple coordinated groups for coordinated MIMO transmission, and the BSs within each coordinated group negotiate a common radio resource region (a composite time-frequency region), and selects a serving mobile station to participate in the coordinated MIMO transmission.

The invention provides systems and methods for providing improved wireless data communication. Preferred embodiments of the present invention utilize multiple antenna beams in the forward link to provide increased forward link capacity and / or improved forward link signal quality. Multiple orthogonal sub-pilots are transmitted from a plurality of antenna elements for use in determining forward link channel characteristics according to a preferred embodiment. Forward link channel estimates may then be made by the preferred embodiment subscriber units and provided in a reverse link control channel to the corresponding base station. Multiple beams may also be utilized in the reverse link to provide increased reverse link capacity, such as for use in providing feedback of forward link channel estimates.

Provided is a radio communication device including an information acquisition unit configured to acquire information of a frequency position at which predetermined indispensable information is allocated in a data area of a downlink subframe transmitted by an adjacent base station, and a virtual carrier transmission control unit configured to transmit a virtual carrier in a data area of a downlink subframe of a current cell in a manner that the virtual carrier does not overlap with the frequency position at which the predetermined indispensable information is allocated, the virtual carrier having a narrower band than a donor band.

Disclosed is a method for generating and transmitting a reference signal in a clustered DFT-spread OFDM transmission scheme. A method for generating and transmitting a DM-RS in a clustered DFT-spread-OFDM scheme comprises: a step of generating DM-RS sequences corresponding to the number of clusters allocated for an uplink transmission; and a step of mapping the generated DM-RS sequences to the relevant DM-RS symbol positions for each cluster. Accordingly, the method for generating and transmitting a reference signal according to the present invention, in which DM-RS sequences are allocated and transmitted on a cluster basis, uses a complete DM-RS sequence for each cluster, and therefore inter-cell interference can be weakened, and problems which might occur when applied to a multi-user MIMO (MU-MIMO) scheme can be solved.

A data transmission method and apparatus using a multi-point cooperative transmission for a backhaul link transmission of a relay communication system. A data transmission method of a base station in a radio relay communication system include: obtaining, by a first BS, first radio resource information scheduled by a neighbor BS with respect to a first relay node (RN) located within the coverage of the first BS; when the first BS has data to be transmitted to the first RN, scheduling the data of the first BS on first radio resource allocated by the neighbor BS; and transmitting, by the first BS, the data of the first BS on the first BS, wherein the first RN is located within an overlapping cell coverage between the first BS and the neighbor BS. Thus, backhaul link transmission efficiency between the BS and the RN in the relay communication system can be improved and an inter-cell interference with respect to a backhaul link can be reduced.

The present invention pertains to the technology for avoiding interference between adjacent frequencies occurring on cell boundaries or sector boundaries in a mobile wireless communication system using an OFDMA (Orthogonal Frequency Division Multiple Access) scheme. There are a single sector mode of no collaboration between sectors; a sector selection mode of collaborating between sectors to transmit with a specified frequency resource from only one sector, and a collaboration mode of collaborating between sectors to transmit signals from both sectors. Any of the three modes is selected on the basis of measurement results of RSRP (Reference Signal Received Power) reported from a mobile station.

Power control methods and apparatus for use in a sectorized cell of an OFDM communications system are described. Each sector of a cell uses the same frequencies and transmission times and is synchronized with the other sectors in the cell in terms of tone frequencies used at any given time and symbol transmission times. Tones are allocated to channels in each cell in the same manner so that each channel in a sector has a corresponding channel in another sector. Power differences between channels in different sectors are maintained to be within a pre-selected power difference. Different channels in a cell are assigned different power levels. Wireless terminals are assigned to channels based on channel feedback information. Wireless terminals with poor channel conditions are allocated to higher power channels than wireless terminals with good channel conditions. Lower power channels often include more tones per symbol time than high power channels.

Methods are provided for mitigating interference due to pilot contamination in a cellular network in which there is reuse of pilot signals. In embodiments, forward-link signals are precoded, using knowledge of slow-fading coefficients, to mitigate the interference. In embodiments, interference in reverse-link signals destined for a given base station is mitigated by linearly combining reverse-link signals destined for the given base station and for other base stations of the network, using knowledge of slow-fading coefficients.

A few high power tones used for synchronization and / or other purposes are transmitted in a FDM system during a period of time into a region, e.g., sector of a cell, e.g., a symbol transmission time period. During normal data transmission symbol periods signals are transmitted using at least 10 tones, e.g., per symbol time. Less than 5 high power signals are transmitted in a symbol time with at least 80% the maximum total transmitter power used for transmitting into said region being allocated to the high power signals where the maximum total transmitter power is determined from a period of time which may includes one or more data and / or high power tone transmission periods. When the high power tones are transmitted at most 20% of transmitter power used for transmitting into the region is available for transmitting other tones with the power normally being distributed among multiple tones. Often some tones which would be transmitted in a symbol time go unused during transmission of the high power signals.

In embodiments of the present disclosure improved capabilities are described for reducing inter-cell interference in a large area broadband LTE wireless network utilizing RF agile beam forming antennas, where the reduced inter-cell interference is realized by arranging the sets of rotating RF beams in each cell such that adjacent RF beam sub-areas in the same or in different cells are not illuminated at the same time. The reduction in inter-cell interference results in reduced interference noise for users located near the edges of cells, thereby allowing them to be assigned higher data rates. Also, the same set of sub-carriers can be assigned by adjacent cells to users located in the RF beam sub-areas at the cell boundaries, thereby allowing the complete set of LTE sub-carriers to be assigned to any user at any time, without requiring additional cell-to-cell communications.

A method is described for reducing interferences in a wireless network, by: identifying cells which experience more interference than others; identifying a group of PRBs that their transmissions are subjected to moire interference than other concurrent transmissions; identifying UEs associated with the group of PRBs, and determining whether the location of the UEs is at the cells' edges; selecting a pair of UEs where one member is located at a first cell's edge and the other is located either (i) at a second cell, not included within a neighbors' list of the first cell, or (ii) at the core or remote edge of a second cell. In case (i), the second cell is introduced to the first cell neighbors' list, and in case (ii) the other UE is falsely defined as a UE located at the near second cell's edge. Then, ICIC procedure is invoked for that pair of UEs.

A resource allocation control method and device that can reduce inter-cell interference in a radio communications system are provided. According to a method for resource allocation control between a plurality of cells in a radio communications system, radio communication devices respectively controlling at least two cells notify information about control resources of its own cell to each other. In the resources of its own cell, each of the radio communication devices sets a buffer resource within a predetermined resource range corresponding to a control resource of the other cell. At a request for information transmission in its own cell, each of the radio communication devices restricts the allocation of the set buffer resource.

A method allocates resource in an Orthogonal Frequency-Division Multiple Access (OFDMA) network, including a set of Base Stations (BSs) and a set of Mobile Stations (MSs) for each BS. OFDMA frame are constructed as multiple resource blocks, and each resource block contains symbols transmitted on different subcarriers. A cluster is formed from adjacent sectors of different neighboring cells to jointly optimize the resource allocation in multiple frames, and three non-overlap zones are sequentially identified in cluster: cell center zone, cell edge zone, and cluster corner zone. Resource allocation includes intra-cluster proportional fair scheduling and inter-cluster interference mitigation. Intra-cluster scheduling further includes resource allocation for cell center zone and resource allocation for cell edge zone.

A method and an apparatus for determining the configuration mode of special subframe of a cell are provided, and the method includes: receiving notification messages sent from adjacent cells, and the notification messages containing the information indicating the configuration modes of special subframes of the adjacent cells; determining the configuration modes of special subframes of the adjacent cells in accordance with the notification messages; among the possible configuration modes of special subframes of the current cell, selecting preferably a configuration mode of special subframe, which meets the interference requirement of the current cell and has less interference with the adjacent cells, as the current configuration mode of special subframe. The embodiments of the present invention also provide a method and an apparatus for determining the usage mode of the time-domain resource of a cell.