New! View global litigation for patent families

US20090285146A1 - Methods for improving range for multicast wireless communication - Google Patents

Methods for improving range for multicast wireless communication Download PDF

Info

Publication number
US20090285146A1
US20090285146A1 US12535200 US53520009A US2009285146A1 US 20090285146 A1 US20090285146 A1 US 20090285146A1 US 12535200 US12535200 US 12535200 US 53520009 A US53520009 A US 53520009A US 2009285146 A1 US2009285146 A1 US 2009285146A1
Authority
US
Grant status
Application
Patent type
Prior art keywords
ap
transmit
data
range
signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12535200
Inventor
Gary L. Sugar
Chandra Vaidyanathan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
IPR Licensing Inc
Original Assignee
IPR Licensing Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/26Systems using multi-frequency codes
    • H04L27/2601Multicarrier modulation systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0667Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal
    • H04B7/0669Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal using different channel coding between antennas
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0667Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal
    • H04B7/0671Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal using different delays between antennas
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/0842Weighted combining
    • H04B7/0845Weighted combining per branch equalization, e.g. by an FIR-filter or RAKE receiver per antenna branch
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/0842Weighted combining
    • H04B7/0848Joint weighting
    • H04B7/0854Joint weighting using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837Diversity systems; Multi-antenna systems, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/0842Weighted combining
    • H04B7/0848Joint weighting
    • H04B7/0857Joint weighting using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/02Arrangements for detecting or preventing errors in the information received by diversity reception
    • H04L1/06Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; Arrangements for supplying electrical power along data transmission lines
    • H04L25/0202Channel estimation
    • H04L25/0204Channel estimation of multiple channels
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; Arrangements for supplying electrical power along data transmission lines
    • H04L25/03Shaping networks in transmitter or receiver, e.g. adaptive shaping networks ; Receiver end arrangements for processing baseband signals
    • H04L25/03006Arrangements for removing intersymbol interference
    • H04L2025/03433Arrangements for removing intersymbol interference characterised by equaliser structure
    • H04L2025/03439Fixed structures
    • H04L2025/03445Time domain
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATIONS NETWORKS
    • H04W52/00Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04TPC [Transmission power control]
    • H04W52/38TPC being performed in particular situations
    • H04W52/42TPC being performed in particular situations in systems with time, space, frequency or polarisation diversity

Abstract

An extended range mode for wireless communication of a multicast data signal from an access point (AP) to multiple stations (STAs) may be enabled or disabled. When the extended range mode is enabled, the AP transmits the data signal up to a total of N times using a transmit delay diversity, where N is the number of transmit antennas.

Description

    CROSS REFERENCE TO RELATED APPLICATION(S)
  • [0001]
    This application is a divisional of U.S. Application Ser. No. 10/855,279, filed May 27, 2004, which in turn claims priority to U.S. Application Ser. No. 10/174,690, filed Jun. 19, 2002, which in turn claims priority to U.S. Provisional Application No. 60/365,774, filed Mar. 21, 2002, and to U.S. Provisional Application No. 60/361,055, filed Mar. 1, 2002, the entirety of which are incorporated herein by reference.
  • BACKGROUND OF THE INVENTION
  • [0002]
    The present invention relates to enhancing the range in a wireless communication application where communication devices may transmit multicast signals as well as directed signals.
  • [0003]
    Composite Beamforming (CBF) is an antenna processing technique in which a first communication device, having a plurality of antennas, weights a signal to be transmitted by its antennas to a second communication device also having a plurality of antennas. Similarly, the second communication device weights and combines the received signals received by its antennas. The transmit weights and receive weights are determined to optimize the link margin between the devices, thereby significantly extending the range of communication between the two communication devices. Techniques related to composite beamforming are the subject matter of commonly assigned co-pending applications filed on even date and entitled “System and Method for Antenna Diversity Using Joint Maximal Ratio Combining” and “System and Method for Antenna Diversity Using Equal Gain Joint Maximal Ratio Combining,” the entirety of both which are incorporated herein by reference. There are other techniques to improve the link margin for directed signal transmissions between two communication devices, including antenna selection diversity, for example.
  • [0004]
    Link margin improvement translates into a corresponding improvement in range, data rate at a given range, infrastructure cost to support a given data rate, and interference immunity. However, the range improvement afforded by CBF applies to signals that are sent in a point-to-point fashion from one device to another. Many wireless applications also require multicast signal communication, i.e., point to multi-point. Therefore, to improve the overall range related parameters of a wireless application, it is necessary to also improve the range of multicast signal transmissions. No such range improvement techniques for multicast communication are heretofore known.
  • SUMMARY OF THE INVENTION
  • [0005]
    Methods are described which optimize range of multicast signal communication in wireless communication applications that use range-enhanced techniques for directed signal communication. An extended range mode for wireless communication of a multicast data signal from an access point (AP) to multiple stations (STAs) may be enabled or disabled. When the extended range mode is enabled, the AP transmits the data signal up to a total of N times using a transmit delay diversity, where N is the number of transmit antennas.
  • [0006]
    A multicast signal may be sent multiple times through each of a plurality of independent omnidirectional transmit antennas of a communication device to a plurality of other communication devices to improve packet error rate (PER) at a given range (i.e., SNR). More generally, the multicast signal can be transmitted up to N times using any set of N complex linearly independent N-dimensional transmit weight vectors ν1, . . . νN associated with N plurality of transmit antennas that meets the power constraint ∥νi2=1, i=0, . . . , N−1 where the vector νi is used for the ith transmission of the multicast signal.
  • [0007]
    Other objects and advantages of the present invention will become more readily apparent when reference is made to the following description in conjunction with the accompanying drawings.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0008]
    FIG. 1 is a block diagram of a wireless communication network comprising a plurality of communication terminals.
  • [0009]
    FIG. 2 a block diagram of an exemplary communication device suitable for use in the processes described herein.
  • [0010]
    FIG. 3 is a flow chart illustrating a procedure for transmitting multicast signals in a wireless communication network.
  • [0011]
    FIG. 4 is a flow chart illustrating a procedure for transmitting a beacon type message.
  • [0012]
    FIG. 5 is a flow chart illustrating a procedure for transmitting directed data from an access point.
  • [0013]
    FIG. 6 is a flow chart illustrating a procedure for transmitting directed data from a station not using a clear-to-send/request-to-send process.
  • [0014]
    FIG. 7 is a flow chart illustrating a procedure for transmitting directed data from a station using a clear-to-send/request-to-send process.
  • [0015]
    FIG. 8 is a flow chart illustrating a procedure for communication when a point coordination function is enabled in the network.
  • [0016]
    FIG. 9 is a timing diagram showing the repetitive transmission of certain multicast signals.
  • DETAILED DESCRIPTION
  • [0017]
    With reference first to FIG. 1, an example of a wireless application, such as a short-range wireless communication network 100 is shown. The wireless network is, for example, an IEEE 802.11x wireless local area network (WLAN), comprising an access point (AP) 110 and a plurality of stations (STAs) 120, 130, 140 and 150.
  • [0018]
    When two devices are in direct communication with each other, they use range-enhancement techniques, such as antenna selection diversity, composite beamforming, etc., for directed signal communication. For example, at least the AP 110, as well as some or all of the STAs have two or more antennas and are capable of performing composite beamforming Specifically, a STA, such as STA 120, may have two antennas and when it transmits to another communication device in the network, such as the AP 110, it scales the transmit signal by complex transmit antenna weights wtx1 and wtx2 for the respective antennas. Similarly, when receiving a signal from the plurality of antennas of another device, such as the AP, it combines the signals received at its two antennas with complex receive antenna weights wrx1 and wrx2. The receive antenna weights are usually matched to the received signal at the antennas. The AP 110 has four antennas and therefore can perform 4x-beamforming when transmitting to another device and receiving from another device. Each device may determine and use optimum transmit antenna weights for a particular destination device through techniques described in the aforementioned co-pending application. In addition, each device may store this information for future use against an identifier for the corresponding destination device for use when transmitted to that device. The transmit antenna weights used by a device may are dependent on the particular destination device. Likewise, no two devices may use the same transmit antenna weights when transmitting to the same destination device. The transmit and receive antenna weights may be frequency dependent. When composite beamforming (CBF) is used between two communication devices that are in direct communication with each other, dramatic improvement in range is achieved as described in the aforementioned co-pending application. The communication devices may use other range enhancement techniques, such as antenna selection diversity, as opposed to CBF.
  • [0019]
    Again, the antenna processing techniques described above impact directed signal communication. In order to improve all around range performance, it is also necessary to improve the range for multicast signal communication. What follows are techniques to improve range for broadcast or multicast signal communication where CBF is used to extend range for point-to-point signal communication. The terms “unicast”, “point-to-point” and “directed” are used synonymously and interchangeably herein. Likewise, the terms “broadcast” and “multicast” are used interchangeably.
  • [0020]
    In a wireless network, such as the one shown in FIG. 1, range is important in when the user density (i.e., the demand for bandwidth) is relatively low, infrastructure cost (i.e., access point (AP) density) is critical, or both. Examples of such environments are home, home office and lightly populated corporate or campus environments.
  • [0021]
    Capacity C of a WLAN is average throughput per unit area (in kbps per square meters. Some general rules of thumb for network planning are:
  • [0022]
    Enterprise Wired LAN: 1 user per 250 sq. ft, 100 kbps per user: C=4 kbps/m2
  • [0023]
    Enterprise WLAN (office environment): C=0.5-4 kbps/m2
  • [0024]
    Conference rooms, public areas: C=10 kbps/m2
  • [0025]
    Airports, lecture halls, hotel lobbies, etc.: C=10-20 kbps/m2
  • [0026]
    Range is generally not important for high-capacity applications (i.e., for C>˜4 kbps/m2). For these applications, data rate at range, becomes the important network design parameter.
  • [0027]
    In a wireless communication network application that operates in a coverage area (e.g., a cell), the “range” of a cell may be defined by a radius around a communication device that achieves a certain error rate. For example, the range of an IEEE 802.11x cell is the maximum cell radius satisfying both of the following conditions at a specified AP/STA transmit power level:
      • 1. 10% PER at the lowest data rate (e.g., 6 Mbps for 802.11a) for unicast data with a 5% outage probability (due to fading); and
      • 2. Multicast data and beacon messages can be received w/PER<=10% with a 5% outage probability.
  • [0030]
    For an 802.11a AP with 2-selection diversity in an indoor delay spread environment, the range is approximately 55 meters (Ptx=17 dBm). For 802.11b, the range is approximately 115 meters (Ptx=20 dBm).
  • [0031]
    A device, such as the AP 110, may have different range modes, including a range-enhanced mode. For example, a network administrator may program this mode at the AP whenever range is to be extended (at the expense of less system throughput) beyond that of a single (omnidirectional) transmit (Tx) antenna for multicast signals. The AP may be configured to operate in directed range-enhanced mode, such as CBF mode where a signal (packet, etc.) is transmitted through all four antennas simultaneously with corresponding transmit antenna weights. Alternatively, the AP may be configured to operate in the omnidirectional mode (omni-mode) where a packet is transmitted through one of four antennas at the same total output power as CBF mode.
  • [0032]
    When directed signals are transmitted, the devices at both ends of the link use a range enhancement technique, such as CBF. When multicast signals are transmitted, there are several other range enhancement techniques that can be summarized as follows. A multicast signal may be transmitted multiple times, each time through a different one of a plurality of independent omnidirectional transmit antennas of a communication device to a plurality of other communication devices to improve packet error rate (PER) at a given range (i.e., SNR). More generally, the multicast signal can be transmitted up to N times using any set of N complex linearly independent N-dimensional transmit weight vectors ν1, . . . , νN associated with N plurality of transmit antennas that meets the power constraint ∥νi2=1, i=0, . . . , N−1 and the vector vi is used for the ith transmission of the multicast signal. For certain multicast signals that are transmitted repeatedly, such signals are transmitted in a round-robin fashion, cycling through the N antennas, ad infinitum for each scheduled transmission of the signal. To more broadly state this latter case, the ith transmission is sent using transmit weight vector νmod(i,N), for the ith transmission of the signal, where mod(m,n) denotes the remainder of m divided by n, where i is not bounded by N. By transmitting the multicast signal in this manner, the communication, will receive the signal, is greatly enhanced.
  • [0033]
    When it is necessary to reserve the radio frequency medium for directed signals, the source communication device precedes the transmission of the directed signals by sending a sequence of multicast clear-to-send (CTS) frames (once through each omnidirectional antenna or more generally each CTS transmission using one of the complex linearly independent N dimensional transmit weight vectors described above). Each CTS includes information that informs the plurality of other communication devices of the impending data transmission, thereby reserving the medium before data transmission. When reserving the medium for certain types of data, such as isochronous data, the AP transmits basic network information together with a delivery traffic indication map after the 4 CTS frames are sent. Any of these schemes can be further enhanced by transmitting the multicast signal with transmit delay diversity.
  • [0034]
    FIG. 2 illustrates a block diagram of a STA or AP 200 that can be used for any one of the terminals shown in FIG. 1. The terminal in FIG. 3 comprises at least two antennas, though four antennas 202, 204, 206 and 208 are shown such as would be the case for the AP. An RF section 210 is coupled to the antennas 202-208, and includes a transmitter (Tx) 212 and a receiver (Rx) 214. A baseband section 220 is coupled to the RF section 210. The baseband section 220 may include a CPU or processor 222 and memory 224. The processor 222 performs the processing steps in the communication device that are described hereinafter. The memory 224 stores the channel transfer function information (e.g., transmit antenna weights) associated with a particular destination device that is retrievable by the processor 222. For example, the memory 224 is random access memory (RAM). The CPU 222 executes instructions that are stored or encoded on a processor readable medium that when cause the CPU to perform the processes described above in conjunction with FIG. 2. Alternatively, the baseband section may be implemented by a digital application specific integrated circuit (ASIC) with a synthesized processor core and/or may include dedicated processor functionality such as field programmable gates that implement digital signal processor instructions to perform the processes described herein. The baseband section 220 is coupled to a host processor 230. Still another alternative is for the processing steps to be performed by a host processor 232 (in a host 230) by executing instructions stored in (or encoded on) a processor readable memory 234. The RF section 210 may be embodied by one integrated circuit, and the baseband section 220 may be embodied by another integrated circuit. The communication device on each end of the communication link need not have the same device architecture or implementation.
  • [0035]
    The baseband section 220, either by way of the processor 222, or through other dedicated functionality (such as field programmable gates) multiplies the signal to be transmitted by corresponding transmit antenna weights and likewise multiplies signals received at each of the antennas by corresponding receive antenna weights and combines the resulting signals to recover the received signal therefrom. When it is stated hereinafter that a communication device transmits a signal to another communication using “CBF”, this means that the transmitting communication device multiplies the signal by transmit antenna weights (corresponding to the plurality of antennas of the transmitting communication device) corresponding to a destination device, that optimize reception of the signal at the destination device. The transmit and receive antenna weights have real and imaginary components (magnitude and phase) that may vary with frequency to account for the frequency response of the communication medium between transmit and receive communication devices, as described in the aforementioned co-pending applications. When transmitting a signal through a single antenna, the baseband section 220 multiplies the signal with a transmit weight vector that weights one antenna and nulls all of the other antennas. For example, to select antenna 202 (out of four antennas), the transmit weight vector is (1 0 0 0), to select antenna 204, the transmit weight vector is (0 1 0 0), etc. More generally, the processor in the baseband section 220 processes the multicast signal using any set of N complex linearly independent N-dimensional transmit weight vectors ν1, . . . , νN associated with N plurality of transmit antennas that meets the power constraint ∥νi2=1, i=0, . . . , N−1 where the vector vi is used for the ith transmission of the multicast signal. For example, for N=4, one transmission of the multicast signal is sent with the transmit weight vector (1 0 1 0) and the next transmission it is sent with the transmit weight vector (0 1 0 1), and so on.
  • [0036]
    The transmitter 312 upconverts signals to be transmitted by the antennas 302-308 and the receiver 314 downconverts signals received by the antennas. In the case where the terminal has just two antennas to perform antenna selection diversity, there is a switch in the RF section that selects one of the two antennas for reception of transmission of signals.
  • [0037]
    FIG. 3 shows a process 300 for transmitting a multicast data signal from an AP to multiple (or all) STAs. For example, the data unit is a media service data unit (MSDU) or a MAC protocol data unit (MPDU) according to IEEE 802.1 lx WLAN protocol. In step 310, the AP determines whether the extended mode of operation is enabled or disabled. If the extended mode is disabled, then in step 320, the AP transmits the data unit once from of its plurality of antennas. If it is determined in step 310 that the extended mode is enabled, then in step 330, the AP transmits the data unit up to a total of N times, once through each of its plurality of antennas, or more generally, the AP may send the data unit up to N times using any set of N complex linearly independent N-dimensional transmit weight vectors ν1, . . . , νN associated with N plurality of transmit antennas that meets the power constraint ∥νi2=1, i=0, . . . , N−1 where the vector νi is used for the ith transmission of the multicast signal. This approach gives significant improvement in PER (at the expense of lower throughput) due to antenna diversity and repeated transmission by increasing the likelihood that the data unit will be received by each STA. When implementing this approach, the AP uses the Sequence Number and Retry subfields in the MAC header to ensure proper duplicate filtering in the STAs.
  • [0000]
    TABLE 1
    0 ns RMS Delay Spread 50 ns RMS Delay Spread 150 ns RMS Delay Spread
    N = # 2-WBS 2-CBF 4-CBF 2-WBS 2-CBF 4-CBF 2-WBS 2-CBF 4-CBF
    Repetitions STAs STAs STAs STAs STAs STAs STAs STAs STAs
    1 0 2 9 0.5 4 9 1 5.5 10
    2 8.5 9.5 13 7.5 9 14 6 9 14
    4 10.5 11.5 14 8.5 11 14 8 10 14
  • [0038]
    Table 1 above shows, through simulations, sensitivity improvement in dB at 10% PER for 802.11a at 24 Mbps relative to the 2-WBS, delay spread=0 ns, N=1 case. “WBS” means STAs using 2-antenna wideband selection diversity as opposed to CBF enhanced STAs.
  • [0039]
    FIG. 3 also shows other alternatives to step 330. For example, in step 340, to improve range, the AP may send the data unit once using transmit delay diversity. This means essentially that a delay is introduced between the transmissions of the data unit among the plurality of AP antennas according to a transmit x(t)=[x0(t), x1(t−τD), . . . , xNt−1(t−Nt−1))τD] where N is the number of AP antennas used for transmission and τD, a transmit delay parameter. In essence, the signal will be sent from each antenna with a different delay spread and such that the maximum delay to spread between any two antennas is (N−1)τD It has been found through performance simulations that a transmit delay parameter τD of 1000 ns provides optimal delay spread, but can be programmable to span 50 ns to 150 ns, for example.
  • [0040]
    Still another alternative shown in step 350 is to transmit the data unit a total of N times (up to the number of antennas), each time using transmit delay diversity (as described above).
  • [0041]
    FIG. 4 shows a process 400 for transmitting another type of multicast signal that is used to inform all communication devices (e.g. STAs) about subsequent signals scheduled for transmission on the radio frequency medium. As an example, this multicast signal is a Beacon frame that is sent when the point coordination function (PCF) is disabled. PCF is an IEEE 802.11x function that is a centrally controlled access mechanism that uses a poll and response protocol to eliminate the possibility of contention for the medium. The PCF will be described further below. According to the IEEE 802.11x WLAN protocol, the Beacon frame is transmitted periodically to allow mobile stations to locate and identify a basic service set (BSS) in time and physical parameters at any time in the future. The Beacon frame also conveys information to stations about frames that may be buffered during times of low power operation. Elements of a Beacon frame include the service set identity (SSID), the supported rates of the BSS, one or more PHY parameter sets, an optional contention-free parameter set, an optional IBSS parameter set and an optional traffic indication map.
  • [0042]
    If the extended range mode is disabled (step 410), then in step 420, the AP transmits a Beacon frame through one antenna at the minimum data rate required to support all associated STAs. If the extended range mode is enabled, then in step 430, the AP transmits the Beacon frame sequentially through each antenna, moving to the next AP antennas each time the Beacon frame is scheduled to be transmitted, in a round-robin fashion at a minimum data rate required to support all STAs, ad infinitum for Beacon transmissions. The same power save (PS) list is used for all Beacons. This process provides significant performance enhancement relative to the single antenna case, since each STA sees multiple repetitions of the Beacon with independent fading for up to four repetitions.
  • [0043]
    Again, more generally, the Beacon can be transmitted using the transmit weight vector νmod(i,N), ith transmission of the Beacon, where mod(m,n) denotes the remainder of m divided by n. In this case, the number of transmissions i is not bounded by N−1. This is useful for sending Beacon frames on an ongoing, repetitive basis.
  • [0044]
    Data from Table 1 can be used to quantify performance. For an indoor environment w/50 ns delay spread, for example, a STA can reliably decode a beacon after 2 repetitions using 7.5 dB less Rx power, and after 4 repetitions using 8.5 dB less power.
  • [0045]
    Like the multicast data unit process of FIG. 3, the Beacon frame can alternatively be transmitted once through using transmit delay diversity, or N times, each time using transmit delay diversity.
  • [0046]
    FIG. 5 shows a process 500 for transmitting directed data from a source communication device (the AP) to a destination communication device (a particular STA). The data may be, for example, a directed MSDU or MPDU. In order to transmit the directed data, the source communication device reserves the communication medium by alerting all of the other communication devices (with a multicast signal) of the impending data transmission. In step 510, the AP determines whether the extended range mode is enabled. When it is not enabled, the frame sequence is {CTS-} {frag-ACK-} last ACK. Specifically, in step 520, the AP sends a clear-to-send (CTS) frame through one AP antennas to announce to all STAs in the neighborhood of both the AP and the destination STA of the impending transmission from the AP to the destination STA. The CTS is optional and only necessary if system simulations show that other STAs have difficulty receiving directed data units sent in CBF mode. Next, in step 530, the AP transmits the data unit to the destination STA using CBF. In step 540, if and when the STA receives the data unit, it transmits an acknowledgment frame (ACK) to the AP using CBF.
  • [0047]
    If in step 510, the AP determines that the extended range mode is enabled, then the sequence is {CTSxN-} {frag-ACK-} last-ACK. Specifically, in step 550, CTSxN is a sequence of up to N CTS frames (N equals the number of AP antennas) each CTS frame sent through a different AP antenna and used to set the network allocation vector (NAV) for STAs other than the destination STA. More generally, the CTS frame is sent up to N times any set of N complex linearly independent N-dimensional transmit weight vectors ν1, . . . , νN associated with N plurality of transmit antennas that meets the power constraint where the vector vi is used for the ith transmission of the multicast signal. The NAV is an 802.11x frame that informs STAs of the amount of time before the medium will become available. In step 560, the AP transmits the data unit to the destination STA using CBF, and in step 570, when the STA receives the data unit, it transmits an ACK to the AP using CBF.
  • [0048]
    Like the process of FIG. 3, the CTS frame can alternatively be transmitted once through an antenna using transmit delay diversity, or N times, each time using transmit delay diversity.
  • [0049]
    FIG. 6 shows a process 600 useful when a STA sends a directed data unit (MSDU or MPDU) without the request-to-send (RTS)/CTS scheme. The RTS frame is a signal directed to the AP that requests the AP to reserve the medium for transmission of data from the STA to the AP. The sequence {frag-ACK-} last-ACK is useful regardless of whether the extended range mode is enabled or disabled. In step 610, the STA transmits one or more data fragments to the AP using CBF. In step 620, if and when the AP receives the data fragments, it transmits an ACK to the STA using CBF.
  • [0050]
    FIG. 7 illustrates a process 700 useful when a STA transmits a directed data unit using the RTS/CTS scheme. In step 705, the STA sends an RTS frame to the AP using a directed range-enhancement technique, such as CBF, and upon receiving the RTS frame the AP determines whether the extended range mode is enabled. If the extended range mode is not enabled when the AP receives the RTS, then the sequence is CTS-{frag-ACK-} last-ACK. Specifically, in step 720, in response to receiving the RTS, the AP transmits a CTS frame through one AP antenna. In response to receiving the CTS, in step 730, the STA transmits the data unit using CBF. In step 740, when the AP receives the data unit, it transmits an ACK using CBF.
  • [0051]
    When the AP receives the RTS and determines that the extended range mode is enabled, the sequence is:
  • [0000]
    CTS*-timeout-backoff-RTS- CTS-{frag-ACK-}last-ACK. Specifically, in step 750, in response to receiving the RTS, the AP transmits a sequence of first and second consecutive CTS frames addressed to the AP each time using a transmit weight vector that is in the null space of H, where H represents the channel response matrix between the AP and the sending STA, such that when the CTS frames are transmitted by the AP antennas, a null is placed at the sending STA's antennas. Furthermore, in addition to being in the null space of H, the transmit weight vectors for the two CTS frames may be linearly independent transmit weight vectors in order to improve performance by generating independent fading for each CTS. Such can be the case if the AP has four antennas and the STAs have two antennas, so that there are at least two linearly independent vectors in the null space of H. The AP can determine the channel response matrix H when it receives a signal, such as an RTS frame, from the STA, as described in the aforementioned co-pending applications incorporated herein by reference, and from that information determine the transmit weight vector that satisfies this condition.
  • [0052]
    This sequence is referred to as CTS* and it ensures that all STAs except the sending STA receive at least one of the CTS frames and stay off the medium during the data transmission. Since the sending STA does not receive either CTS*frame (due to the null), in step 755, the sending STA will generate a CTS timeout, execute a back-off, and in step 760 send a second RTS packet (using CBF if it is CBF-capable). In step 770, the AP responds to the second RTS by transmitting a CTS frame (using CBF) addressed to the sending STA. In step 780, the STA responds to the CTS and transmits a data fragment burst using CBF. In step 790, when the AP receives the data fragments, it transmits an ACK using CBF. The network allocation vector (NAV) in the CTS* sequence is long enough to complete this transaction in the worst case.
  • [0053]
    FIG. 8 shows a process 900 useful for the PCF operation. In the PCF operation, a point coordinator (PC) located in an AP receives requests from STAs to register them on a polling list, and the PC then regularly polls the STAs for traffic while also delivering traffic to the STAs. The PCF is able to deliver near-isochronous service to the STAs on the polling list. The PCF is built over the distributed coordination function (DCF) and both operate simultaneously. When the extended range mode is disabled (step 805), in step 810 the AP transmits frames as follows.
  • [0054]
    Beacon+DTIM: Omni mode
  • [0055]
    Cf-poll: CBF mode
  • [0056]
    Cf-ACK: CBF mode
  • [0057]
    Data: CBF mode
  • [0058]
    ACK: CBF mode
  • [0059]
    Cf-ACK+data, Cf-ACK+Data+Cf-Poll, Cf-ACK+Cf-Poll: Omni mode
  • [0000]
    The STA transmits frames in step 820 as follows.
  • [0060]
    Cf-ACK: CBF mode
  • [0061]
    Data: CBF mode
  • [0062]
    Data+Cf-ACK: CBF mode
  • [0063]
    ACK: CBF mode
  • [0064]
    Null: CBF mode
  • [0065]
    In step 830, operation when the extended range mode is enabled is the same as when the extended range mode is disabled, except that the AP precedes each Beacon+DTIM (delivery traffic indication map) with a sequence of up to 4 CTS frames each sent through a different AP antenna, or each sent with up to N times using any set of N complex linearly independent N-dimensional transmit weight vectors ν1, . . . , νN associated with N plurality of transmit antennas that meets the power constraint ∥νi2=1, i=0, . . . , N−1 where the vector vi is used for the ith transmission of the multicast signal. The CTS frames reserve the medium prior to the contention free period (CFP) for the entire duration of the CFP, and the repetition of these packets improves the likelihood that at least one CTS is received by all STAs in extended range mode. The Beacon frame is sent in this case through one antenna. The 4 CTS frames will reserve the medium for the duration of the contention free period (CFP) even if the beacon is not received by some STAs. The PCF operation is useful for communication of isochronous data, such as voice or video.
  • [0066]
    Like the process of FIG. 3, the CTS frame of step 830 can alternatively be transmitted once using transmit delay diversity, or N times, each time using transmit delay diversity.
  • [0067]
    Other frames of interest are STA initiated sequences including the PS-Poll sequence and the announcement traffic indication map (ATIM) frame. In the PS-Poll scheme, a PS-Poll is sent from the STA using CBF and the AP sends an ACK using CBF. For the ATIM frame, the ATIM is sent from an otherwise CBF-capable STA using a single antenna. Alternatively, a STA can send a directed ATIM in CBF mode.
  • [0000]
    TABLE 2
    Typical
    2-WBS 2-WBS NIC, 2-CBF NIC, 4-CBF NIC,
    Case NIC + AP 4-CBF AP 4-CBF AP 4-CBF AP
    Directed Data - AP to STA (dB) 0 11 14 16.5
    Directed Data - STA to AP (dB) 0 11 14 16.5
    Multicast Messages (dB) 0 8 10 14
    Beacons (dB) 0 8 10 14
    Minimum of Above (dB) 0 8 10 14
    Range Improvement (%) 0% 75% 101% 166%
    Coverage Area Improvement (%) 0% 205%  304% 605%
    Reduction in AP density (%) 0% 67%  75%  86%
  • [0068]
    Table 2 shows the range improvement for CBF-enhanced 802.11 a relative to a “typical” NIC+AP case, using the enhancements described above (typical means 2-antenna wideband selection diversity on both NIC and AP). The first four rows show link margin improvement (in dB) for directed data, multicast data and Beacons and the information for multicast data and beacons is taken from Table 1, where it is assumed both multicast messages are repeated 4 times through each Tx antenna, and Beacons are sent round-robin through each antenna. Range improvements are computed as 101 mi/33, where 1 mi represents the minimum link margin improvement over rows 1-4 in the table, and 33 represents the path loss coefficient for the indoor wireless channel.
  • [0069]
    To summarize, the range improvements over the typical AP+NIC case are:
  • [0070]
    75% percent range improvement (8 dB) for 4x-CBF AP and typical NICs;
  • [0071]
    100% percent range improvement (10 dB) for 4x-CBF AP and 2x-CBF NICs; and
  • [0072]
    166% percent range improvement (14 dB) for 4x-CBF AP and 4x-CBF NICs.
  • [0073]
    FIG. 9 illustrates a timing diagram to depict the timing of transmission of the multicast signals of FIGS. 3-5 and 8. FIG. 9 shows that an AP having four antennas that, as one example, transmits the multicast data unit (DU) once from each antenna Ant1 through Ant4 sequentially in time. Similarly, the AP transmits a CTS frame once from each antenna Ant1 through Ant4. The AP transmits the Beacon frame once from each antenna Ant1 through Ant4 in a round-robin fashion for each scheduled Beacon frame. These are simplified examples of the more general case where the transmit antenna weight vectors can be any set of N complex linearly independent N-dimensional transmit weight vectors ν1, . . . , νN associated with N plurality of transmit antennas that meets the power constraint ∥νi2=1.
  • [0074]
    To summarize, techniques are provided to enhance the range of multicast signals by transmitting the signal up to N times any set of N complex linearly independent N-dimensional transmit weight vectors ν1, . . . , νN associated with N plurality of transmit antennas that meets the power constraint ∥νi2=1, i=0, . . . , N−1 where the vector v1 is used for the ith transmission of the signal. Other related methods are provided to enhance the range of multicast signals, such as the method of responding to a RTS signal from a communication device and sending at least one CTS signal using a transmit weight vector that is in the null space of the channel response matrix between the two communication devices. These methods may be implemented by instructions encoded on a medium, such as processor readable medium, or field programmable gates on an integrated circuit.
  • [0075]
    The above description is intended by way of example only.

Claims (8)

  1. 1. A method for transmitting a multicast data signal from an access point (AP) having a plurality of N antennas to multiple stations (STAs), comprising:
    determining whether an extended range mode is enabled in the AP;
    transmitting the data signal once through the N antennas, on a condition that the extended range mode is disabled; and
    transmitting the data signal up to a total of N times using transmit delay diversity through the N antennas, on a condition that the extended range mode is enabled.
  2. 2. The method as in claim 1, wherein the extended range mode comprises using antenna processing techniques to maximize the range of communication between the AP and the STAS, the antenna processing techniques including composite beamforming.
  3. 3. The method as in claim 1, wherein the transmit delay diversity includes a delay between the transmissions of the data among a plurality of AP antennas according to a transmit vector x(t)=[x0(t), x1(t−τD), . . . , xNt−1(t−Nt−1))τD], where τD is a transmit delay parameter.
  4. 4. The method as in claim 3, further comprising sending the data signal from each antenna such that the maximum delay spread between any two antennas is (N−1)τD.
  5. 5. An access point (AP) configured to transmit a multicast data signal to multiple stations (STAs), comprising:
    a plurality of N antennas;
    a processor configured to determine whether an extended range mode is enabled in the AP; and
    a transmitter configured to transmit a data signal once through the N antennas on a condition that the extended range mode is disabled, and further configured to transmit the data signal up to a total of N times using transmit delay diversity through the N antennas on a condition that the extended range mode is enabled.
  6. 6. The AP as in claim 5, wherein the processor is further configured to execute the extended range mode for the AP using antenna processing techniques to maximize the range of communication between the AP and the STAs, the antenna processing techniques including composite beamforming.
  7. 7. The AP as in claim 5, wherein the processor is further configured to determine the transmit delay diversity as a delay between the transmissions of the data among the N antennas according to a transmit vector x(t)=[x0(t), x1(t−τD), . . . , xNt−1(t−Nt−1))τD], where τD is a transmit delay parameter.
  8. 8. The AP as in claim 5, wherein the processor is further configured to determine the maximum delay spread between any two antennas as (N−1)τD.
US12535200 2002-03-01 2009-08-04 Methods for improving range for multicast wireless communication Abandoned US20090285146A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US36105502 true 2002-03-01 2002-03-01
US36577402 true 2002-03-21 2002-03-21
US10174690 US6862456B2 (en) 2002-03-01 2002-06-19 Systems and methods for improving range for multicast wireless communication
US10855279 US7570921B2 (en) 2002-03-01 2004-05-27 Systems and methods for improving range for multicast wireless communication
US12535200 US20090285146A1 (en) 2002-03-01 2009-08-04 Methods for improving range for multicast wireless communication

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US12535200 US20090285146A1 (en) 2002-03-01 2009-08-04 Methods for improving range for multicast wireless communication

Publications (1)

Publication Number Publication Date
US20090285146A1 true true US20090285146A1 (en) 2009-11-19

Family

ID=28046310

Family Applications (3)

Application Number Title Priority Date Filing Date
US10174690 Expired - Fee Related US6862456B2 (en) 2002-03-01 2002-06-19 Systems and methods for improving range for multicast wireless communication
US10855279 Expired - Fee Related US7570921B2 (en) 2002-03-01 2004-05-27 Systems and methods for improving range for multicast wireless communication
US12535200 Abandoned US20090285146A1 (en) 2002-03-01 2009-08-04 Methods for improving range for multicast wireless communication

Family Applications Before (2)

Application Number Title Priority Date Filing Date
US10174690 Expired - Fee Related US6862456B2 (en) 2002-03-01 2002-06-19 Systems and methods for improving range for multicast wireless communication
US10855279 Expired - Fee Related US7570921B2 (en) 2002-03-01 2004-05-27 Systems and methods for improving range for multicast wireless communication

Country Status (3)

Country Link
US (3) US6862456B2 (en)
EP (1) EP1543628A4 (en)
WO (1) WO2003075470A3 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090117894A1 (en) * 2007-11-02 2009-05-07 Yuki Kogure Wireless Diversity Reception Apparatus and Reception Method
US20110081875A1 (en) * 2009-10-02 2011-04-07 Sharp Laboratories Of America, Inc. Antenna port mode and transmission mode transitions
US20110081934A1 (en) * 2009-10-02 2011-04-07 Sharp Laboratories Of America, Inc. Transmission power control on a wireless communication device for a plurality of regulated bands or component carriers
US20110199953A1 (en) * 2008-10-15 2011-08-18 Yong Ho Seok Method for multicast frame transmission and duplicated multicast frame detection

Families Citing this family (57)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7146176B2 (en) 2000-06-13 2006-12-05 Shared Spectrum Company System and method for reuse of communications spectrum for fixed and mobile applications with efficient method to mitigate interference
US6862456B2 (en) * 2002-03-01 2005-03-01 Cognio, Inc. Systems and methods for improving range for multicast wireless communication
WO2003075471A3 (en) * 2002-03-01 2004-04-08 Cognio Inc System and method for joint maximal ratio combining
US6785520B2 (en) 2002-03-01 2004-08-31 Cognio, Inc. System and method for antenna diversity using equal power joint maximal ratio combining
US6871049B2 (en) 2002-03-21 2005-03-22 Cognio, Inc. Improving the efficiency of power amplifiers in devices using transmit beamforming
US7742443B2 (en) * 2002-05-28 2010-06-22 Maarten Menzo Wentink Transmit power management in shared-communications channel networks
DK1540830T3 (en) * 2002-07-30 2009-05-04 Ipr Licensing Inc System and method for multi-input Rights (MIMO) radio communication
US7099678B2 (en) * 2003-04-10 2006-08-29 Ipr Licensing, Inc. System and method for transmit weight computation for vector beamforming radio communication
US8170611B2 (en) * 2002-09-04 2012-05-01 Symbol Technologies, Inc. Internal accessory antenna system and method for wireless network
EP1570589A1 (en) * 2002-12-04 2005-09-07 Philips Electronics N.V. Delay diversity in a wireless communication system
US7933255B2 (en) * 2003-04-07 2011-04-26 Bellow Bellows Llc Multi-antenna wireless data processing system
US7409010B2 (en) * 2003-06-10 2008-08-05 Shared Spectrum Company Method and system for transmitting signals with reduced spurious emissions
US7515541B2 (en) * 2003-08-08 2009-04-07 Intel Corporation Transmission of data with feedback to the transmitter in a wireless local area network or the like
KR100542348B1 (en) * 2003-09-03 2006-01-10 삼성전자주식회사 apparatus and method of power saving in wireless LAN system
US7385914B2 (en) * 2003-10-08 2008-06-10 Atheros Communications, Inc. Apparatus and method of multiple antenna transmitter beamforming of high data rate wideband packetized wireless communication signals
US8213301B2 (en) * 2003-11-07 2012-07-03 Sharp Laboratories Of America, Inc. Systems and methods for network channel characteristic measurement and network management
EP1692619B1 (en) * 2003-11-07 2013-01-09 Sharp Kabushiki Kaisha Methods and systems for network coordination
WO2005071903A1 (en) * 2004-01-22 2005-08-04 Telefonaktiebolaget Lm Ericsson (Publ) Access control for multicast channel request
US8199686B1 (en) * 2004-03-04 2012-06-12 Marvell International Ltd. Wireless local area network infrastructure mode for reducing power consumption
US7289828B2 (en) * 2004-03-17 2007-10-30 Interdigital Technology Corporation Method for steering a smart antenna for a WLAN using a periodic re-scan
US7424007B2 (en) * 2004-05-12 2008-09-09 Cisco Technology, Inc. Power-save method for 802.11 multicast paging applications
US8280443B2 (en) * 2004-07-30 2012-10-02 Hong Kong Applied Science And Technology Research Institute Co., Ltd. WLAN access point with extended coverage area
US20060083240A1 (en) * 2004-10-19 2006-04-20 Padcom, Inc. Broadcasting data over multiple dissimilar wireless networks
WO2006052943A3 (en) * 2004-11-08 2007-02-22 Toyota Technical Ct Usa Inc System and method of vehicular wireless communication
WO2006055719A3 (en) * 2004-11-16 2006-07-20 Univ Texas Precoding system and method for multi-user transmission in multiple antenna wireless systems
US7382758B2 (en) * 2004-11-30 2008-06-03 Motorola, Inc. Medium access control for simultaneous channel communications
WO2006089568A1 (en) * 2005-02-25 2006-08-31 Ntt Docomo, Inc. Receiver and transmitter for a network having a non-centralized medium access control
CN101238648B (en) 2005-06-14 2013-03-20 高通股份有限公司 Method and device for broadcast and multicast from cellular wireless networks
US8059608B2 (en) * 2005-06-14 2011-11-15 Qualcomm Incorporated Transmit spatial diversity for cellular single frequency networks
CN101253705A (en) * 2005-09-01 2008-08-27 夏普株式会社 Wireless transmitting device and wireless transmitting method
JP4920595B2 (en) 2005-10-31 2012-04-18 シャープ株式会社 Transmission control method, a communication terminal and a communication system
ES2378714T3 (en) * 2005-10-31 2012-04-17 Sharp Kabushiki Kaisha wireless receiver
KR100770073B1 (en) * 2005-11-23 2007-10-24 인스티튜트 포 인포메이션 인더스트리 Method and Apparatus for Efficient Data Broadcast Within Beaconing Network
US7564816B2 (en) * 2006-05-12 2009-07-21 Shared Spectrum Company Method and system for determining spectrum availability within a network
US8155649B2 (en) 2006-05-12 2012-04-10 Shared Spectrum Company Method and system for classifying communication signals in a dynamic spectrum access system
US8326313B2 (en) * 2006-05-12 2012-12-04 Shared Spectrum Company Method and system for dynamic spectrum access using detection periods
US9538388B2 (en) * 2006-05-12 2017-01-03 Shared Spectrum Company Method and system for dynamic spectrum access
EP2033385A4 (en) * 2006-06-23 2013-08-21 Bae Sys Inf & Elect Sys Integ Supporting mobile ad-hoc network (manet) and point to multi-point (pmp) communications among nodes in a wireless network
US8027249B2 (en) 2006-10-18 2011-09-27 Shared Spectrum Company Methods for using a detector to monitor and detect channel occupancy
US8997170B2 (en) 2006-12-29 2015-03-31 Shared Spectrum Company Method and device for policy-based control of radio
US7747285B2 (en) * 2007-07-11 2010-06-29 Alcatel-Lucent Usa Inc. Method of transmit beamforming for multicasting in a wireless communication system
US8068877B1 (en) * 2007-07-20 2011-11-29 Clear Wireless Llc Systems and methods of antenna selection
US8055204B2 (en) 2007-08-15 2011-11-08 Shared Spectrum Company Methods for detecting and classifying signals transmitted over a radio frequency spectrum
US8184653B2 (en) 2007-08-15 2012-05-22 Shared Spectrum Company Systems and methods for a cognitive radio having adaptable characteristics
EP2319260A2 (en) * 2008-08-19 2011-05-11 Shared Spectrum Company Method and system for dynamic spectrum access using specialty detectors and improved networking
EP2184880A1 (en) * 2008-11-07 2010-05-12 Thomson Licensing A method of data rate adaptation for multicast communication
US8406720B2 (en) * 2009-08-19 2013-03-26 Cisco Technology, Inc. Beamforming weight generation using adaptive trigonometric waveform interpolation techniques
EP2577885B1 (en) 2010-06-01 2014-09-03 Telefonaktiebolaget LM Ericsson (publ) Method and radio base station for switching between unicast and broadcast modes in a wireless communication system
CN103354999B (en) 2010-11-18 2017-04-19 Aereo公司 System and method for providing an antenna feed network access
EP2676451A1 (en) 2011-02-18 2013-12-25 Aereo, Inc. Cloud based location shifting service
WO2013063134A1 (en) 2011-10-26 2013-05-02 Aereo, Inc. Method and system for assigning antennas in dense array
US9295022B2 (en) * 2012-05-18 2016-03-22 Comcast Cable Communications, LLC. Wireless network supporting extended coverage of service
US20140146734A1 (en) * 2012-11-26 2014-05-29 Qualcomm Incorporated Systems and methods for power conservation in wireless networks
US9001867B2 (en) 2013-02-13 2015-04-07 Qualcomm Incorporated Method and apparatus for managing interference in full-duplex communication
US20140273874A1 (en) * 2013-03-15 2014-09-18 Thorsten Clevorn Communications terminal, a network component, a method for transmitting a signal, and a method for providing feedback information to a communications terminal
KR101516271B1 (en) * 2013-11-14 2015-05-04 광주과학기술원 Wireless communication system and packet communication therefor
US9451474B2 (en) * 2014-07-21 2016-09-20 Aruba Networks, Inc. Multicast aware beamforming for wireless local area networks

Citations (106)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4599734A (en) * 1984-04-10 1986-07-08 Nec Corporation Space diversity communications system for multi-direction time division multiplex communications
US4639914A (en) * 1984-12-06 1987-01-27 At&T Bell Laboratories Wireless PBX/LAN system with optimum combining
US4811420A (en) * 1987-07-08 1989-03-07 International Mobile Machines Corporation Initialization of communication channel between a subsciber station and a base station in a subscriber communication system
US5394435A (en) * 1992-12-29 1995-02-28 At&T Corp. Diversity for direct-sequence spread spectrum systems
US5414699A (en) * 1993-09-27 1995-05-09 Motorola, Inc. Method and apparatus for receiving and decoding communication signals in a CDMA receiver using partial de-correlation
US5437055A (en) * 1993-06-03 1995-07-25 Qualcomm Incorporated Antenna system for multipath diversity in an indoor microcellular communication system
US5491723A (en) * 1993-05-06 1996-02-13 Ncr Corporation Wireless communication system having antenna diversity
US5493307A (en) * 1994-05-26 1996-02-20 Nec Corporation Maximal deversity combining interference cancellation using sub-array processors and respective delay elements
US5493722A (en) * 1994-01-24 1996-02-20 Ingersoll-Rand Company Method for controlling data transmissions on a single channel radio frequency network
US5507035A (en) * 1993-04-30 1996-04-09 International Business Machines Corporation Diversity transmission strategy in mobile/indoor cellula radio communications
US5539832A (en) * 1992-04-10 1996-07-23 Ramot University Authority For Applied Research & Industrial Development Ltd. Multi-channel signal separation using cross-polyspectra
US5610617A (en) * 1995-07-18 1997-03-11 Lucent Technologies Inc. Directive beam selectivity for high speed wireless communication networks
US5621732A (en) * 1994-04-18 1997-04-15 Nec Corporation Access method and a relay station and terminals thereof
US5752173A (en) * 1994-06-07 1998-05-12 Nec Corporation Diversity communication system with adaptably oriented multiple beam patterns
US5761237A (en) * 1994-02-10 1998-06-02 International Business Machines Corporation Method and apparatus for multiuser-interference reduction
US5761193A (en) * 1996-05-31 1998-06-02 Derango; Mario F. Method for pre-establishing communications in a wireless communication network
US5771462A (en) * 1995-07-07 1998-06-23 International Business Machines Corporation Bus arbitration infrastructure for deployment of wireless networks
US5898679A (en) * 1996-12-30 1999-04-27 Lucent Technologies Inc. Wireless relay with selective message repeat and method of operation thereof
US5912921A (en) * 1997-08-20 1999-06-15 Intermec Ip Corp. Concurrent multiple data rate communications in a wireless local area network
US5924020A (en) * 1995-12-15 1999-07-13 Telefonaktiebolaget L M Ericsson (Publ) Antenna assembly and associated method for radio communication device
US5930248A (en) * 1997-03-04 1999-07-27 Telefonaktiebolaget Lm Ericsson Radio communication system selectively using multicast with variable offset time
US6018642A (en) * 1995-12-08 2000-01-25 Fujitsu Limited Radio communications system, base station for radio communications system, and intermittent power-on type mobile station
US6023625A (en) * 1997-02-18 2000-02-08 Ericsson Inc. System and method for reducing multicast interference in a distributed antenna network
US6037898A (en) * 1997-10-10 2000-03-14 Arraycomm, Inc. Method and apparatus for calibrating radio frequency base stations using antenna arrays
US6038272A (en) * 1996-09-06 2000-03-14 Lucent Technologies Inc. Joint timing, frequency and weight acquisition for an adaptive array
US6044120A (en) * 1997-05-01 2000-03-28 Lucent Technologies Inc. Time-varying weight estimation
US6058105A (en) * 1997-09-26 2000-05-02 Lucent Technologies Inc. Multiple antenna communication system and method thereof
US6064338A (en) * 1998-03-19 2000-05-16 Fujitsu Limited Array antenna system of wireless base station
US6091934A (en) * 1997-09-02 2000-07-18 Hughes Electronics Corporation Dynamic power allocation system and method for multi-beam satellite amplifiers
US6177906B1 (en) * 1999-04-01 2001-01-23 Arraycomm, Inc. Multimode iterative adaptive smart antenna processing method and apparatus
US6185440B1 (en) * 1997-12-10 2001-02-06 Arraycomm, Inc. Method for sequentially transmitting a downlink signal from a communication station that has an antenna array to achieve an omnidirectional radiation
US6195045B1 (en) * 1999-01-29 2001-02-27 Cwill Telecommunication, Inc. Adaptive antenna array system calibration
US6211671B1 (en) * 1994-07-22 2001-04-03 Genghiscomm Corporation Interference-cancellation system for electromagnetic receivers
US6218986B1 (en) * 1997-04-02 2001-04-17 Matsushita Electric Industrial Co., Ltd. Adaptive reception diversity method and adaptive transmission diversity method
US6249250B1 (en) * 1998-01-08 2001-06-19 Kabushiki Kaisha Toshiba Adaptive variable directional antenna
US6252548B1 (en) * 1998-06-23 2001-06-26 Samsung Electronics Co., Ltd. Transceiver arrangement for a smart antenna system in a mobile communication base station
US6252884B1 (en) * 1998-03-20 2001-06-26 Ncr Corporation Dynamic configuration of wireless networks
US6266528B1 (en) * 1998-12-23 2001-07-24 Arraycomm, Inc. Performance monitor for antenna arrays
US20010053699A1 (en) * 1999-08-02 2001-12-20 Mccrady Dennis D. Method and apparatus for determining the position of a mobile communication device
US20020001316A1 (en) * 2000-06-29 2002-01-03 California Amplifier, Inc. Modulation methods and structures for wireless communication systems and transceivers
US6349219B1 (en) * 1999-03-01 2002-02-19 Lucent Technologies Inc. Antenna array having reduced sensitivity to frequency-shift effects
US6351499B1 (en) * 1999-12-15 2002-02-26 Iospan Wireless, Inc. Method and wireless systems using multiple antennas and adaptive control for maximizing a communication parameter
US20020024975A1 (en) * 2000-03-14 2002-02-28 Hillel Hendler Communication receiver with signal processing for beam forming and antenna diversity
US20020034191A1 (en) * 1998-02-12 2002-03-21 Shattil Steve J. Method and apparatus for transmitting and receiving signals having a carrier interferometry architecture
US6362781B1 (en) * 2000-06-30 2002-03-26 Motorola, Inc. Method and device for adaptive antenna combining weights
US20020039884A1 (en) * 2000-02-12 2002-04-04 Koninklijke Philips Electronics N.V.. Radio communication system
US6369758B1 (en) * 2000-11-01 2002-04-09 Unique Broadband Systems, Inc. Adaptive antenna array for mobile communication
US6370182B2 (en) * 2000-02-10 2002-04-09 Itt Manufacturing Enterprises, Inc. Integrated beamforming/rake/mud CDMA receiver architecture
US6369458B2 (en) * 1998-05-22 2002-04-09 Mannesmann Vdo Ag Electronic central locking system
US20020045435A1 (en) * 2000-10-18 2002-04-18 Steve Fantaske Wireless communication system
US6377636B1 (en) * 1999-11-02 2002-04-23 Iospan Wirless, Inc. Method and wireless communications system using coordinated transmission and training for interference mitigation
US6377631B1 (en) * 1996-08-29 2002-04-23 Cisco Systems, Inc. Transmitter incorporating spatio-temporal processing
US6377819B1 (en) * 2000-04-06 2002-04-23 Iospan Wireless, Inc. Wireless communication system using joined transmit and receive processing
US20020051430A1 (en) * 2000-10-31 2002-05-02 Hideo Kasami Wireless communication system, weight control apparatus, and weight vector generation method
US6389056B1 (en) * 1999-03-22 2002-05-14 Golden Bridge Technology, Inc. Pre-data power control common packet channel
US20020064246A1 (en) * 2000-11-27 2002-05-30 California Amplifier, Inc. Spatial-temporal methods and systems for reception of non-line-of-sight communication signals
US6400699B1 (en) * 2000-09-12 2002-06-04 Iospan Wireless, Inc. Transmission scheduler for a multiple antenna wireless cellular network
US6400780B1 (en) * 1998-11-06 2002-06-04 Lucent Technologies Inc. Space-time diversity for wireless systems
US20020067309A1 (en) * 2000-12-02 2002-06-06 Koninklijke Philips Electronics N.V. Radio communication system
US20020072392A1 (en) * 2000-05-05 2002-06-13 Awater Geert Arnout Increased data communication capacity of a high rate wireless network
US20020085643A1 (en) * 2000-12-28 2002-07-04 Dean Kitchener MIMO wireless communication system
US20020158801A1 (en) * 2001-04-27 2002-10-31 Crilly William J. Wireless packet switched communication systems and networks using adaptively steered antenna arrays
US20030002450A1 (en) * 2001-06-22 2003-01-02 Ahmad Jalali Method and apparatus for transmitting data in a time division duplexed (TDD) communication system
US20030022693A1 (en) * 2001-07-26 2003-01-30 Marios Gerogiokas System and method for beam on demand
US20030032423A1 (en) * 1998-05-01 2003-02-13 Tibor Boros Determining a calibration function using at least one remote terminal
US6522898B1 (en) * 1999-05-24 2003-02-18 Toshiba Tec Kabushiki Kaisha Radio communication system
US20030035491A1 (en) * 2001-05-11 2003-02-20 Walton Jay R. Method and apparatus for processing data in a multiple-input multiple-output (MIMO) communication system utilizing channel state information
US20030048761A1 (en) * 2001-09-10 2003-03-13 The Boeing Company Packet-based downlink level control
US6549786B2 (en) * 1994-07-29 2003-04-15 International Business Machines Corporation Method and apparatus for connecting a wireless LAN to a wired LAN
US6560299B1 (en) * 1999-07-30 2003-05-06 Christopher H Strolle Diversity receiver with joint signal processing
US6570929B1 (en) * 1999-07-08 2003-05-27 Telefonaktiebolaget Lm Ericsson (Publ) Power control scheme for maximizing carrier signal-to-noise ratio in multicarrier transmitters
US20030100324A1 (en) * 2001-11-28 2003-05-29 Kasapi Athanasios Agamamnon Variable diversity transmission in a radio communications system based on characteristics of a received signal
US20030108117A1 (en) * 2001-12-07 2003-06-12 Ketchum John W. Time-domain transmit and receive processing with channel eigen-mode decompositon for MIMO systems
US20030114108A1 (en) * 2001-12-19 2003-06-19 Alcatel Method and system for increasing the spectrum efficiency in a radio transmission system
US6584161B2 (en) * 1999-05-19 2003-06-24 Nokia Corporation Transmit diversity method and system
US20030125090A1 (en) * 2001-11-29 2003-07-03 Interdigital Technology Corporation Efficient multiple input multiple output system for multi-path fading channels
US20030139194A1 (en) * 2001-11-21 2003-07-24 Onggosanusi Eko N. Closed-loop transmit diversity scheme in frequency selective multipath channels
US6625162B2 (en) * 1997-12-17 2003-09-23 Canon Kabushiki Kaisha Method and apparatus for data transmission with control over access to a transmission medium
US6684064B2 (en) * 2000-03-29 2004-01-27 Interdigital Technology Corp. Dynamic bias for RF power amplifiers
US6687492B1 (en) * 2002-03-01 2004-02-03 Cognio, Inc. System and method for antenna diversity using joint maximal ratio combining
US20040072546A1 (en) * 2002-03-01 2004-04-15 Cognio, Inc. System and Method for Antenna Diversity Using Equal Power Joint Maximal Ratio Combining
US6728517B2 (en) * 2002-04-22 2004-04-27 Cognio, Inc. Multiple-input multiple-output radio transceiver
US6728294B1 (en) * 1999-05-24 2004-04-27 Toshiba Tec Kabushiki Kaisha Radio communication system
US20040104839A1 (en) * 1996-10-10 2004-06-03 Teratech Corporation Communication system using geographic position data
US6771989B1 (en) * 1999-05-01 2004-08-03 Nokia Networks Oy Method of directional radio communication
US6862271B2 (en) * 2002-02-26 2005-03-01 Qualcomm Incorporated Multiple-input, multiple-output (MIMO) systems with multiple transmission modes
US6873606B2 (en) * 2002-10-16 2005-03-29 Qualcomm, Incorporated Rate adaptive transmission scheme for MIMO systems
US6873651B2 (en) * 2002-03-01 2005-03-29 Cognio, Inc. System and method for joint maximal ratio combining using time-domain signal processing
US6888878B2 (en) * 2001-03-12 2005-05-03 Motorola, Inc. Signal combining within a communication system
US6895255B1 (en) * 2000-10-20 2005-05-17 Symbol Technologies, Inc. Dual mode wireless data communications
US6901122B2 (en) * 2001-03-27 2005-05-31 Motorola Method and apparatus for restoring a soft decision component of a signal
US6904021B2 (en) * 2002-03-15 2005-06-07 Meshnetworks, Inc. System and method for providing adaptive control of transmit power and data rate in an ad-hoc communication network
US6961545B2 (en) * 2001-04-09 2005-11-01 Atheros Communications, Inc. Method and system for providing antenna diversity
US6983167B2 (en) * 2001-08-07 2006-01-03 Kabushiki Kaisha Toshiba Wireless communication system and wireless station
US7027536B1 (en) * 1999-10-08 2006-04-11 At&T Corp. Method and apparatus for designing finite-length multi-input multi-output channel shortening pre-filters
US7031368B1 (en) * 1998-06-30 2006-04-18 Nec Corporation Adaptive transmitter/receiver
US7224758B1 (en) * 2001-03-23 2007-05-29 Via Telecom Co., Ltd. Multiple transmit antenna weighting techniques
US7224942B2 (en) * 2001-07-26 2007-05-29 Telefonaktiebolaget Lm Ericsson (Publ) Communications system employing non-polluting pilot codes
US7277409B1 (en) * 2002-02-07 2007-10-02 Broadcom Corporation Wireless local area network management
US7299071B1 (en) * 1997-12-10 2007-11-20 Arraycomm, Llc Downlink broadcasting by sequential transmissions from a communication station having an antenna array
US7340279B2 (en) * 2001-03-23 2008-03-04 Qualcomm Incorporated Wireless communications with an adaptive antenna array
US7342875B2 (en) * 2000-11-06 2008-03-11 The Directv Group, Inc. Space-time coded OFDM system for MMDS applications
US7543945B2 (en) * 2003-09-17 2009-06-09 Samsung Electronics Co., Ltd. Integrator module with a collimator and a compact light source and projection display having the same
US7570921B2 (en) * 2002-03-01 2009-08-04 Ipr Licensing, Inc. Systems and methods for improving range for multicast wireless communication
US7805167B1 (en) * 1999-03-16 2010-09-28 Telefonaktiebolaget Lm Ericsson (Publ) Telecommunications system, base station thereof and telecommunications method
US8224263B2 (en) * 2005-12-20 2012-07-17 Sharp Kabushiki Kaisha Transmitter for communications system

Family Cites Families (46)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4121221A (en) 1977-03-14 1978-10-17 Raytheon Company Radio frequency array antenna system
US5457808A (en) 1992-02-04 1995-10-10 Nec Corporation Point-to-multipoint communication network capable of retransmitting a multicast signal
US5274844A (en) 1992-05-11 1993-12-28 Motorola, Inc. Beam pattern equalization method for an adaptive array
CA2129199C (en) * 1994-07-29 1999-07-20 Roger Y.M. Cheung Method and apparatus for bridging wireless lan to a wired lan
CA2137587C (en) * 1994-12-08 1999-03-23 Murray Charles Baker Broadcast/multicast filtering by the bridge-based access point
US5854611A (en) 1995-07-24 1998-12-29 Lucent Technologies Inc. Power shared linear amplifier network
US6157843A (en) * 1996-05-31 2000-12-05 Motorola, Inc. Method for pre-establishing communications in a wireless communication network without the use of a multicast server
US6097771A (en) * 1996-07-01 2000-08-01 Lucent Technologies Inc. Wireless communications system having a layered space-time architecture employing multi-element antennas
US5848105A (en) 1996-10-10 1998-12-08 Gardner; William A. GMSK signal processors for improved communications capacity and quality
US6463295B1 (en) 1996-10-11 2002-10-08 Arraycomm, Inc. Power control with signal quality estimation for smart antenna communication systems
GB9621465D0 (en) * 1996-10-15 1996-12-04 Northern Telecom Ltd A radio communications system adaptive antenna
US6122260A (en) * 1996-12-16 2000-09-19 Civil Telecommunications, Inc. Smart antenna CDMA wireless communication system
US6147985A (en) 1997-05-01 2000-11-14 Lucent Technologies Inc. Subspace method for adaptive array weight tracking
US6008760A (en) 1997-05-23 1999-12-28 Genghis Comm Cancellation system for frequency reuse in microwave communications
US6331837B1 (en) 1997-05-23 2001-12-18 Genghiscomm Llc Spatial interferometry multiplexing in wireless communications
US6118788A (en) * 1997-10-15 2000-09-12 International Business Machines Corporation Balanced media access methods for wireless networks
US5982327A (en) 1998-01-12 1999-11-09 Motorola, Inc. Adaptive array method, device, base station and subscriber unit
US6317466B1 (en) 1998-04-15 2001-11-13 Lucent Technologies Inc. Wireless communications system having a space-time architecture employing multi-element antennas at both the transmitter and receiver
US6307882B1 (en) 1998-07-10 2001-10-23 Lucent Technologies Inc. Determining channel characteristics in a space-time architecture wireless communication system having multi-element antennas
US6144651A (en) * 1998-07-17 2000-11-07 Motorola, Inc. Data transmission within a wireless communication system
US6327310B1 (en) 1998-08-14 2001-12-04 Lucent Technologies Inc. Wireless transmission method for antenna arrays, having improved resistance to fading
JP2000082982A (en) 1998-09-03 2000-03-21 Nec Corp Array antenna reception device
US6157340A (en) 1998-10-26 2000-12-05 Cwill Telecommunications, Inc. Adaptive antenna array subsystem calibration
KR20000041527A (en) 1998-12-22 2000-07-15 최승원 Apparatus and method for calculating a most suitable weight vector of an antenna system
US6141393A (en) 1999-03-03 2000-10-31 Motorola, Inc. Method and device for channel estimation, equalization, and interference suppression
US6141567A (en) 1999-06-07 2000-10-31 Arraycomm, Inc. Apparatus and method for beamforming in a changing-interference environment
FI111438B (en) * 1999-07-09 2003-07-15 Nokia Corp The symbol string transmission method
US6295026B1 (en) * 1999-11-19 2001-09-25 Trw Inc. Enhanced direct radiating array
US6298092B1 (en) * 1999-12-15 2001-10-02 Iospan Wireless, Inc. Methods of controlling communication parameters of wireless systems
GB0004121D0 (en) * 2000-02-23 2000-04-12 Koninkl Philips Electronics Nv Communication system and a transmitter for use in the system
US6473467B1 (en) 2000-03-22 2002-10-29 Qualcomm Incorporated Method and apparatus for measuring reporting channel state information in a high efficiency, high performance communications system
EP1152576B8 (en) * 2000-05-05 2009-12-23 Agere Systems, Inc. Joint estimation using the M-algorithm or T-algorithm in multiantenna systems
US6442214B1 (en) * 2000-05-19 2002-08-27 Iospan Wireless, Inc. Diversity transmitter based on linear transform processing of transmitted information
US6985434B2 (en) * 2000-09-01 2006-01-10 Nortel Networks Limited Adaptive time diversity and spatial diversity for OFDM
US20020111142A1 (en) * 2000-12-18 2002-08-15 Klimovitch Gleb V. System, apparatus, and method of estimating multiple-input multiple-output wireless channel with compensation for phase noise and frequency offset
US6980600B1 (en) 2000-12-26 2005-12-27 Nortel Networks Limited Receiver system for Multiple-Transmit, Multiple-Receive (MTMR) wireless communications systems
US6987819B2 (en) * 2000-12-29 2006-01-17 Motorola, Inc. Method and device for multiple input/multiple output transmit and receive weights for equal-rate data streams
US6917820B2 (en) * 2001-01-26 2005-07-12 Stanford University Method and apparatus for selection and use of optimal antennas in wireless systems
US20020172186A1 (en) * 2001-04-09 2002-11-21 Peter Larsson Instantaneous joint transmit power control and link adaptation for RTS/CTS based channel access
US6956907B2 (en) 2001-10-15 2005-10-18 Qualcomm, Incorporated Method and apparatus for determining power allocation in a MIMO communication system
US6646600B2 (en) 2001-11-09 2003-11-11 Harris Corporation Phased array antenna with controllable amplifier bias adjustment and related methods
US6702707B2 (en) * 2002-01-31 2004-03-09 Visteon Global Technologies, Inc. Differential assembly
US7155231B2 (en) 2002-02-08 2006-12-26 Qualcomm, Incorporated Transmit pre-correction in a wireless communication system
US7076263B2 (en) * 2002-02-19 2006-07-11 Qualcomm, Incorporated Power control for partial channel-state information (CSI) multiple-input, multiple-output (MIMO) systems
US6636568B2 (en) 2002-03-01 2003-10-21 Qualcomm Data transmission with non-uniform distribution of data rates for a multiple-input multiple-output (MIMO) system
US6940917B2 (en) 2002-08-27 2005-09-06 Qualcomm, Incorporated Beam-steering and beam-forming for wideband MIMO/MISO systems

Patent Citations (111)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4599734A (en) * 1984-04-10 1986-07-08 Nec Corporation Space diversity communications system for multi-direction time division multiplex communications
US4639914A (en) * 1984-12-06 1987-01-27 At&T Bell Laboratories Wireless PBX/LAN system with optimum combining
US4811420A (en) * 1987-07-08 1989-03-07 International Mobile Machines Corporation Initialization of communication channel between a subsciber station and a base station in a subscriber communication system
US5539832A (en) * 1992-04-10 1996-07-23 Ramot University Authority For Applied Research & Industrial Development Ltd. Multi-channel signal separation using cross-polyspectra
US5394435A (en) * 1992-12-29 1995-02-28 At&T Corp. Diversity for direct-sequence spread spectrum systems
US5507035A (en) * 1993-04-30 1996-04-09 International Business Machines Corporation Diversity transmission strategy in mobile/indoor cellula radio communications
US5491723A (en) * 1993-05-06 1996-02-13 Ncr Corporation Wireless communication system having antenna diversity
US5437055A (en) * 1993-06-03 1995-07-25 Qualcomm Incorporated Antenna system for multipath diversity in an indoor microcellular communication system
US5414699A (en) * 1993-09-27 1995-05-09 Motorola, Inc. Method and apparatus for receiving and decoding communication signals in a CDMA receiver using partial de-correlation
US5493722A (en) * 1994-01-24 1996-02-20 Ingersoll-Rand Company Method for controlling data transmissions on a single channel radio frequency network
US5761237A (en) * 1994-02-10 1998-06-02 International Business Machines Corporation Method and apparatus for multiuser-interference reduction
US5621732A (en) * 1994-04-18 1997-04-15 Nec Corporation Access method and a relay station and terminals thereof
US5493307A (en) * 1994-05-26 1996-02-20 Nec Corporation Maximal deversity combining interference cancellation using sub-array processors and respective delay elements
US5752173A (en) * 1994-06-07 1998-05-12 Nec Corporation Diversity communication system with adaptably oriented multiple beam patterns
US6211671B1 (en) * 1994-07-22 2001-04-03 Genghiscomm Corporation Interference-cancellation system for electromagnetic receivers
US6549786B2 (en) * 1994-07-29 2003-04-15 International Business Machines Corporation Method and apparatus for connecting a wireless LAN to a wired LAN
US5771462A (en) * 1995-07-07 1998-06-23 International Business Machines Corporation Bus arbitration infrastructure for deployment of wireless networks
US5610617A (en) * 1995-07-18 1997-03-11 Lucent Technologies Inc. Directive beam selectivity for high speed wireless communication networks
US6018642A (en) * 1995-12-08 2000-01-25 Fujitsu Limited Radio communications system, base station for radio communications system, and intermittent power-on type mobile station
US5924020A (en) * 1995-12-15 1999-07-13 Telefonaktiebolaget L M Ericsson (Publ) Antenna assembly and associated method for radio communication device
US5761193A (en) * 1996-05-31 1998-06-02 Derango; Mario F. Method for pre-establishing communications in a wireless communication network
US6377631B1 (en) * 1996-08-29 2002-04-23 Cisco Systems, Inc. Transmitter incorporating spatio-temporal processing
US6038272A (en) * 1996-09-06 2000-03-14 Lucent Technologies Inc. Joint timing, frequency and weight acquisition for an adaptive array
US20040104839A1 (en) * 1996-10-10 2004-06-03 Teratech Corporation Communication system using geographic position data
US5898679A (en) * 1996-12-30 1999-04-27 Lucent Technologies Inc. Wireless relay with selective message repeat and method of operation thereof
US6023625A (en) * 1997-02-18 2000-02-08 Ericsson Inc. System and method for reducing multicast interference in a distributed antenna network
US5930248A (en) * 1997-03-04 1999-07-27 Telefonaktiebolaget Lm Ericsson Radio communication system selectively using multicast with variable offset time
US6218986B1 (en) * 1997-04-02 2001-04-17 Matsushita Electric Industrial Co., Ltd. Adaptive reception diversity method and adaptive transmission diversity method
US6044120A (en) * 1997-05-01 2000-03-28 Lucent Technologies Inc. Time-varying weight estimation
US5912921A (en) * 1997-08-20 1999-06-15 Intermec Ip Corp. Concurrent multiple data rate communications in a wireless local area network
US6091934A (en) * 1997-09-02 2000-07-18 Hughes Electronics Corporation Dynamic power allocation system and method for multi-beam satellite amplifiers
US6058105A (en) * 1997-09-26 2000-05-02 Lucent Technologies Inc. Multiple antenna communication system and method thereof
US6037898A (en) * 1997-10-10 2000-03-14 Arraycomm, Inc. Method and apparatus for calibrating radio frequency base stations using antenna arrays
US6185440B1 (en) * 1997-12-10 2001-02-06 Arraycomm, Inc. Method for sequentially transmitting a downlink signal from a communication station that has an antenna array to achieve an omnidirectional radiation
US7299071B1 (en) * 1997-12-10 2007-11-20 Arraycomm, Llc Downlink broadcasting by sequential transmissions from a communication station having an antenna array
US6625162B2 (en) * 1997-12-17 2003-09-23 Canon Kabushiki Kaisha Method and apparatus for data transmission with control over access to a transmission medium
US6249250B1 (en) * 1998-01-08 2001-06-19 Kabushiki Kaisha Toshiba Adaptive variable directional antenna
US20020034191A1 (en) * 1998-02-12 2002-03-21 Shattil Steve J. Method and apparatus for transmitting and receiving signals having a carrier interferometry architecture
US6064338A (en) * 1998-03-19 2000-05-16 Fujitsu Limited Array antenna system of wireless base station
US6252884B1 (en) * 1998-03-20 2001-06-26 Ncr Corporation Dynamic configuration of wireless networks
US20030032423A1 (en) * 1998-05-01 2003-02-13 Tibor Boros Determining a calibration function using at least one remote terminal
US6369458B2 (en) * 1998-05-22 2002-04-09 Mannesmann Vdo Ag Electronic central locking system
US6252548B1 (en) * 1998-06-23 2001-06-26 Samsung Electronics Co., Ltd. Transceiver arrangement for a smart antenna system in a mobile communication base station
US7031368B1 (en) * 1998-06-30 2006-04-18 Nec Corporation Adaptive transmitter/receiver
US6400780B1 (en) * 1998-11-06 2002-06-04 Lucent Technologies Inc. Space-time diversity for wireless systems
US6266528B1 (en) * 1998-12-23 2001-07-24 Arraycomm, Inc. Performance monitor for antenna arrays
US6195045B1 (en) * 1999-01-29 2001-02-27 Cwill Telecommunication, Inc. Adaptive antenna array system calibration
US6349219B1 (en) * 1999-03-01 2002-02-19 Lucent Technologies Inc. Antenna array having reduced sensitivity to frequency-shift effects
US7805167B1 (en) * 1999-03-16 2010-09-28 Telefonaktiebolaget Lm Ericsson (Publ) Telecommunications system, base station thereof and telecommunications method
US6389056B1 (en) * 1999-03-22 2002-05-14 Golden Bridge Technology, Inc. Pre-data power control common packet channel
US6177906B1 (en) * 1999-04-01 2001-01-23 Arraycomm, Inc. Multimode iterative adaptive smart antenna processing method and apparatus
US6771989B1 (en) * 1999-05-01 2004-08-03 Nokia Networks Oy Method of directional radio communication
US6584161B2 (en) * 1999-05-19 2003-06-24 Nokia Corporation Transmit diversity method and system
US6728294B1 (en) * 1999-05-24 2004-04-27 Toshiba Tec Kabushiki Kaisha Radio communication system
US6522898B1 (en) * 1999-05-24 2003-02-18 Toshiba Tec Kabushiki Kaisha Radio communication system
US6570929B1 (en) * 1999-07-08 2003-05-27 Telefonaktiebolaget Lm Ericsson (Publ) Power control scheme for maximizing carrier signal-to-noise ratio in multicarrier transmitters
US6560299B1 (en) * 1999-07-30 2003-05-06 Christopher H Strolle Diversity receiver with joint signal processing
US20010053699A1 (en) * 1999-08-02 2001-12-20 Mccrady Dennis D. Method and apparatus for determining the position of a mobile communication device
US7027536B1 (en) * 1999-10-08 2006-04-11 At&T Corp. Method and apparatus for designing finite-length multi-input multi-output channel shortening pre-filters
US6377636B1 (en) * 1999-11-02 2002-04-23 Iospan Wirless, Inc. Method and wireless communications system using coordinated transmission and training for interference mitigation
US6351499B1 (en) * 1999-12-15 2002-02-26 Iospan Wireless, Inc. Method and wireless systems using multiple antennas and adaptive control for maximizing a communication parameter
US6370182B2 (en) * 2000-02-10 2002-04-09 Itt Manufacturing Enterprises, Inc. Integrated beamforming/rake/mud CDMA receiver architecture
US20020039884A1 (en) * 2000-02-12 2002-04-04 Koninklijke Philips Electronics N.V.. Radio communication system
US20020024975A1 (en) * 2000-03-14 2002-02-28 Hillel Hendler Communication receiver with signal processing for beam forming and antenna diversity
US6684064B2 (en) * 2000-03-29 2004-01-27 Interdigital Technology Corp. Dynamic bias for RF power amplifiers
US6377819B1 (en) * 2000-04-06 2002-04-23 Iospan Wireless, Inc. Wireless communication system using joined transmit and receive processing
US20020072392A1 (en) * 2000-05-05 2002-06-13 Awater Geert Arnout Increased data communication capacity of a high rate wireless network
US20020001316A1 (en) * 2000-06-29 2002-01-03 California Amplifier, Inc. Modulation methods and structures for wireless communication systems and transceivers
US6362781B1 (en) * 2000-06-30 2002-03-26 Motorola, Inc. Method and device for adaptive antenna combining weights
US6400699B1 (en) * 2000-09-12 2002-06-04 Iospan Wireless, Inc. Transmission scheduler for a multiple antenna wireless cellular network
US20020045435A1 (en) * 2000-10-18 2002-04-18 Steve Fantaske Wireless communication system
US6895255B1 (en) * 2000-10-20 2005-05-17 Symbol Technologies, Inc. Dual mode wireless data communications
US20050192048A1 (en) * 2000-10-20 2005-09-01 Raj Bridgelall Dual mode wireless data communications
US20070117513A1 (en) * 2000-10-31 2007-05-24 Hideo Kasami Wireless communication system, weight control apparatus, and weight vector generation method
US7042860B2 (en) * 2000-10-31 2006-05-09 Kabushiki Kaisha Toshiba Wireless communication system, weight control apparatus, and weight vector generation method
US20020051430A1 (en) * 2000-10-31 2002-05-02 Hideo Kasami Wireless communication system, weight control apparatus, and weight vector generation method
US6369758B1 (en) * 2000-11-01 2002-04-09 Unique Broadband Systems, Inc. Adaptive antenna array for mobile communication
US7342875B2 (en) * 2000-11-06 2008-03-11 The Directv Group, Inc. Space-time coded OFDM system for MMDS applications
US20020064246A1 (en) * 2000-11-27 2002-05-30 California Amplifier, Inc. Spatial-temporal methods and systems for reception of non-line-of-sight communication signals
US20020067309A1 (en) * 2000-12-02 2002-06-06 Koninklijke Philips Electronics N.V. Radio communication system
US20020085643A1 (en) * 2000-12-28 2002-07-04 Dean Kitchener MIMO wireless communication system
US6888878B2 (en) * 2001-03-12 2005-05-03 Motorola, Inc. Signal combining within a communication system
US7340279B2 (en) * 2001-03-23 2008-03-04 Qualcomm Incorporated Wireless communications with an adaptive antenna array
US7224758B1 (en) * 2001-03-23 2007-05-29 Via Telecom Co., Ltd. Multiple transmit antenna weighting techniques
US6901122B2 (en) * 2001-03-27 2005-05-31 Motorola Method and apparatus for restoring a soft decision component of a signal
US6961545B2 (en) * 2001-04-09 2005-11-01 Atheros Communications, Inc. Method and system for providing antenna diversity
US20020158801A1 (en) * 2001-04-27 2002-10-31 Crilly William J. Wireless packet switched communication systems and networks using adaptively steered antenna arrays
US6970682B2 (en) * 2001-04-27 2005-11-29 Vivato, Inc. Wireless packet switched communication systems and networks using adaptively steered antenna arrays
US20030035491A1 (en) * 2001-05-11 2003-02-20 Walton Jay R. Method and apparatus for processing data in a multiple-input multiple-output (MIMO) communication system utilizing channel state information
US20030002450A1 (en) * 2001-06-22 2003-01-02 Ahmad Jalali Method and apparatus for transmitting data in a time division duplexed (TDD) communication system
US20030022693A1 (en) * 2001-07-26 2003-01-30 Marios Gerogiokas System and method for beam on demand
US7224942B2 (en) * 2001-07-26 2007-05-29 Telefonaktiebolaget Lm Ericsson (Publ) Communications system employing non-polluting pilot codes
US6983167B2 (en) * 2001-08-07 2006-01-03 Kabushiki Kaisha Toshiba Wireless communication system and wireless station
US20030048761A1 (en) * 2001-09-10 2003-03-13 The Boeing Company Packet-based downlink level control
US20030139194A1 (en) * 2001-11-21 2003-07-24 Onggosanusi Eko N. Closed-loop transmit diversity scheme in frequency selective multipath channels
US20030100324A1 (en) * 2001-11-28 2003-05-29 Kasapi Athanasios Agamamnon Variable diversity transmission in a radio communications system based on characteristics of a received signal
US20030125090A1 (en) * 2001-11-29 2003-07-03 Interdigital Technology Corporation Efficient multiple input multiple output system for multi-path fading channels
US7230940B2 (en) * 2001-12-03 2007-06-12 Psion Teklogix Inc. Wireless communication system
US20030108117A1 (en) * 2001-12-07 2003-06-12 Ketchum John W. Time-domain transmit and receive processing with channel eigen-mode decompositon for MIMO systems
US20030114108A1 (en) * 2001-12-19 2003-06-19 Alcatel Method and system for increasing the spectrum efficiency in a radio transmission system
US7277409B1 (en) * 2002-02-07 2007-10-02 Broadcom Corporation Wireless local area network management
US6862271B2 (en) * 2002-02-26 2005-03-01 Qualcomm Incorporated Multiple-input, multiple-output (MIMO) systems with multiple transmission modes
US6687492B1 (en) * 2002-03-01 2004-02-03 Cognio, Inc. System and method for antenna diversity using joint maximal ratio combining
US20040072546A1 (en) * 2002-03-01 2004-04-15 Cognio, Inc. System and Method for Antenna Diversity Using Equal Power Joint Maximal Ratio Combining
US7570921B2 (en) * 2002-03-01 2009-08-04 Ipr Licensing, Inc. Systems and methods for improving range for multicast wireless communication
US6873651B2 (en) * 2002-03-01 2005-03-29 Cognio, Inc. System and method for joint maximal ratio combining using time-domain signal processing
US6904021B2 (en) * 2002-03-15 2005-06-07 Meshnetworks, Inc. System and method for providing adaptive control of transmit power and data rate in an ad-hoc communication network
US6728517B2 (en) * 2002-04-22 2004-04-27 Cognio, Inc. Multiple-input multiple-output radio transceiver
US6873606B2 (en) * 2002-10-16 2005-03-29 Qualcomm, Incorporated Rate adaptive transmission scheme for MIMO systems
US7543945B2 (en) * 2003-09-17 2009-06-09 Samsung Electronics Co., Ltd. Integrator module with a collimator and a compact light source and projection display having the same
US8224263B2 (en) * 2005-12-20 2012-07-17 Sharp Kabushiki Kaisha Transmitter for communications system

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090117894A1 (en) * 2007-11-02 2009-05-07 Yuki Kogure Wireless Diversity Reception Apparatus and Reception Method
US9113479B2 (en) * 2008-10-15 2015-08-18 Lg Electronics Inc. Method for multicast frame transmission and duplicated multicast frame detection
US9706576B2 (en) 2008-10-15 2017-07-11 Lg Electronics Inc. Method for multicast frame transmission and duplicated multicast frame detection
US20110199953A1 (en) * 2008-10-15 2011-08-18 Yong Ho Seok Method for multicast frame transmission and duplicated multicast frame detection
US8768397B2 (en) 2009-10-02 2014-07-01 Sharp Kabushiki Kaisha Transmission power control on a wireless communication device for a plurality of regulated bands or component carriers
US9049667B2 (en) 2009-10-02 2015-06-02 Sharp Kabushiki Kaisha Transmission power control on a wireless communication device for a plurality of regulated bands or component carriers
US9059749B2 (en) * 2009-10-02 2015-06-16 Sharp Kabushiki Kaisha Antenna port mode and transmission mode transitions
US20110081875A1 (en) * 2009-10-02 2011-04-07 Sharp Laboratories Of America, Inc. Antenna port mode and transmission mode transitions
US20110081934A1 (en) * 2009-10-02 2011-04-07 Sharp Laboratories Of America, Inc. Transmission power control on a wireless communication device for a plurality of regulated bands or component carriers
US9917630B2 (en) 2009-10-02 2018-03-13 Sharp Kabushiki Kaisha Antenna port mode and transmission mode transitions

Also Published As

Publication number Publication date Type
US20040219937A1 (en) 2004-11-04 application
US20030181165A1 (en) 2003-09-25 application
WO2003075470A2 (en) 2003-09-12 application
US7570921B2 (en) 2009-08-04 grant
EP1543628A4 (en) 2010-10-13 application
EP1543628A2 (en) 2005-06-22 application
WO2003075470A3 (en) 2004-04-01 application
US6862456B2 (en) 2005-03-01 grant

Similar Documents

Publication Publication Date Title
US20100177757A1 (en) Method for setting transmission opportunity and for transmitting and receiving data in wireless lan system using multiple channel
US20130329620A1 (en) Method for communication based on identifying information assignment and apparatus for the same
US20110064013A1 (en) Collision mitigation for multicast transmission in wireless local area networks
US20100260091A1 (en) Method and apparatus for processing multicast frame
US7046651B2 (en) System topologies for optimum capacity transmission over wireless local area networks
US20070133447A1 (en) Dual CTS protection systems and methods
US20120008490A1 (en) Method and system for communication in multi-user multiple-input-multiple-output wireless networks
US20090232109A1 (en) Method and System for Optimal Beamforming in Wireless Networks
Yang et al. Performance enhancement of multirate IEEE 802.11 WLANs with geographically scattered stations
US20110317630A1 (en) Method and system for contention avoidance in multi-user multiple-input-multiple-output wireless networks
US20060057964A1 (en) Implementing a smart antenna in wireless local area network
US20060056345A1 (en) Method and system for supporting use of a smart antenna in a wireless local area network
US20110222408A1 (en) Simultaneous transmissions during a transmission opportunity
US7305237B2 (en) Hole-filling channel access
US20110150004A1 (en) Enhanced multi-user transmission
US20110199953A1 (en) Method for multicast frame transmission and duplicated multicast frame detection
US20120087358A1 (en) Method and system for enhanced contention avoidance in multi-user multiple-input-multiple-output wireless networks
US20140119288A1 (en) Method and system for uplink multi-user multiple-input-multiple-output communication in wireless networks
US20050254513A1 (en) Method of selectively adjusting the configuration of an access point antenna to enhance mobile station coverage
US20100118716A1 (en) Method and apparatus for directional clear channel assessment in a wireless communications system
US7031336B2 (en) Space-time-power scheduling for wireless networks
US20110255618A1 (en) Method and system for multi-user transmit opportunity for multi-user multiple-input-multiple-output wireless networks
US20060209876A1 (en) Access point using directional antennas for uplink transmission in a WLAN
US20110205968A1 (en) Method and apparatus for performing sounding in wireless communication system
US20130010664A1 (en) Method for power saving in wireless local area network and apparatus for the same