Abstract: The present invention generally relates to methods and apparatus for precision time transfer wherein the inherent packet delay variation and possible asymmetry introduced in networks is avoided or mitigated. In one embodiment, the timing functions of a master device may be placed closer to a slave device using a Remote Time-Stamp Generator, located in the network between the master and the slave, and whose time reference serves as a proxy for the time reference of the master. Time-of-traversal of packets at the remote time-stamp generator may be used as proxies for the time-of-departure and the time-of-arrival of certain messages at the master. Such proxy times may be used to synchronize the slave with the master, particularly if the master and the Remote Time-Stamp Generator are both synchronized with a Global Navigation Satellite System (GNSS) source.

Abstract: Certain aspects of the present disclosure propose techniques for independently signaling features supported by a user equipment (UE) in different duplexing modes. The UE may be capable of communicating in frequency division duplexing (FDD) and time division duplexing (TDD) modes. The UE may obtain a FDD-specific feature group indicators (FGIs) set and a TDD-specific FGIs set, and signal at least one of the FDD-specific FGIs set or TDD-specific FGIs set. In addition, the UE may take one or more actions to reduce the likelihood of transitioning to a mode of operation that is different from its current mode of operation.

Abstract: A method and apparatus to control interference in a relay node are provided and include simultaneously receiving a symbol from source nodes, adjusting channel coefficients; and relaying the symbol to destination nodes with adjusted channel coefficients. The simultaneously receiving and the relaying are performed during a symbol transmission process between the source and destination nodes.

Abstract: An optical receiver receives a wavelength multiplexed optical signal including wavelength channels. A superimposition signal is superimposed by frequency modulation on each of the wavelength channels. The optical receiver includes: an optical filter that filters the wavelength multiplexed optical signal; a filter controller that controls a wavelength of a transmission band of the optical filter; a photo detector that generates an intensity signal representing a change in the intensity of an output light of the optical filter; an signal detector that detects, according to the intensity signal, a superimposition signal superimposed on a specified wavelength channel. The filter controller controls the wavelength of the transmission band so that the amplitude of the intensity signal is larger, and then controls the wavelength of the transmission band so that the number of errors in the superimposition signal detected by the signal detector is reduced.

Abstract: A method for bandwidth map update includes: after receiving a bandwidth report carried by a control frame, a master node newly establishing a bandwidth map, newly establishing a resource state table, and setting all resource states in the newly established resource state table to be available; adding a cross-master node transport channel drop allocation structure of the newly established bandwidth map in accordance with a cross-master node transport channel add allocation structure of a bandwidth map to be updated, and updating the resource state table; according to the bandwidth report carried by the control frame, allocating a wavelength and an optical burst timeslot one by one to a current bandwidth request, adding wavelengths and optical burst timeslots to the newly established bandwidth map, generating a new bandwidth map, and updating the resource state table; and distributing the control frame carrying the new bandwidth map to slave nodes hop by hop.

Abstract: An apparatus stores information identifying unallocated channels for each of spans, where a span indicates a section between adjacent nodes of a plurality of nodes in a communication network. The apparatus extracts unallocated channels for each of all spans provided between a start point node and an end point node of a path in the communication network, by referring to the information, and determines a channel including consecutive unallocated spans which are arranged on routes including the path and spans outside the path, and whose number is minimum among the extracted unallocated channels, as a channel to be set to the path.

Abstract: An optical transmission and reception system includes a transmitter and receiver. The transmitter differentially encodes control information to generate a differentially coded signal; uses the differentially coded signal to modulate a signal sequence in which electricity concentrates at a particular frequency; applies time-division multiplexing on the modulated signal sequence and a primary signal in one of two polarized wave components, and applies time-division multiplexing on the other polarized wave components and the signal sequence itself; and polarization-multiplexes the both of the time-division multiplexed polarized waves into an optical signal; and transmits the optical signal to the receiver.

Abstract: The present disclosure provides a communication device, including: a reception section that receives information relating to a reception timing at a reception side, which is transmitted from a transmission destination after a data frame is transmitted to the transmission destination; an information storage section that stores a transmission interval and the information relating to the reception timing for previous transmissions; a mismatch correction section that, in a case in which a new data frame is transmitted, calculates a correction amount for eliminating a mismatch in a transmission timing of a wakeup frame or a mismatch in a reception timing at which the transmission destination receives the wakeup frame, based on the transmission interval and the information relating to the reception timing; and a communication control section that determines the transmission or reception timing based on the information relating to the reception timing and the correction amount.

Abstract: An encoder outputs a first bit sequence having N bits. A mapper generates a first complex signal s1 and a second complex signal s2 with use of bit sequence having X+Y bits included in an input second bit sequence, where X indicates the number of bits used to generate the first complex signal s1, and Y indicates the number of bits used to generate the second complex signal s2. A bit length adjuster is provided after the encoder, and performs bit length adjustment on the first bit sequence such that the second bit sequence has a bit length that is a multiple of X+Y, and outputs the first bit sequence after the bit length adjustment as the second bit sequence. As a result, a problem between a codeword length of a block code and the number of bits necessary to perform mapping by a set of modulation schemes is solved.

Abstract: An integrated circuit device includes an output buffer circuit that provides a first output having a first code rate. The first output is provided in response to a first indication of a change in a parameter that affects an error rate of the first output. The first output includes redundant information. The output buffer circuit provides a second output having a second code rate. The second output is provided in response to a second indication of the second output having an error rate that is different than the error rate of the first output. The second code rate of the second output is different than the first code rate.

Abstract: The embodiments of the present invention disclose a configuration method, system and device for an uplink channel. The method includes: The terminal achieve the information the network side device sending of carrying uplink transmission mode, and use the transmission mode transfer uplink signal; the terminal obtains the channel quality information according to the uplink transmission mode; the channel quality information the terminal obtained report to the network side device, as well as enables the network side device configures the uplink channel according to the channel quality information. The present invention performs the configuration of uplink channels in multicarrier transmission.

Abstract: Methods and network entities for communicating control signalling for an uplink high speed data service, a downlink high speed data service or both over a radio interface of a cellular network.

Abstract: A communication method and an apparatus for transferring interference-related control information in order to enhance reception performance of a user terminal that receives downlink signals in a cellular mobile communication system based on a long term evolution-advanced (LTE-A) system are provided. The method includes receiving transmission parameters of interference, which include information on a resource by which interference data is not transmitted, performing blind detection using the information on a resource by which interference data is not transmitted, performing error correction encoding using the transmission parameters of the interference and the blind detection result, and decoding the received data.

Abstract: A method of transmitting a data signal using an optical transmitter of an optical communications system. A first encoder processes an N-bit input vector in accordance with a first mapping to generate a corresponding M-bit data stream. A Forward Error Correction encoder processes the M-bit data stream in accordance with a predetermined FEC encoding scheme to generate an encoded signal. A constellation mapper maps the encoded signal to symbol values in accordance with a predetermined modulation scheme to generate a corresponding symbol stream. A modulator modulates a carrier light in accordance with the encoded symbol stream to generate an optical signal for transmission through the optical communications system. The first mapping can be adjusted to maximize performance of the optical communications system.

Abstract: In various embodiments, a computer-implemented method for optimized data transfer utilizing optimized code table signaling is disclosed. In one embodiment, a computer-implemented method comprises receiving, by a processor, a digital bit stream and transforming, by the processor, the digital bit stream to an encoded digital bit stream. The encoded digital bit stream comprises at least one of a gateway channel, a composite channel, or a data channel, and any combination thereof. The computer-implemented method further comprises providing, by the processor, the encoded digital bit stream to a transmission system for transmission and establishing, by the processor, signal integrity by utilizing pre-coordinated, pre-distributed information to limit the transmission to an intended sender-receiver pair. The intended sender-receiver pair comprises the pre-coordinated, pre-distributed information.

Abstract: Systems and methods for decoding block and concatenated codes are provided. These include advanced iterative decoding techniques based on belief propagation algorithms, with particular advantages when applied to codes having higher density parity check matrices such as iterative soft-input soft-output and list decoding of convolutional codes, Reed-Solomon codes and BCH codes. Improvements are also provided for performing channel state information estimation including the use of optimum filter lengths based on channel selectivity and adaptive decision-directed channel estimation. These improvements enhance the performance of various communication systems and consumer electronics.

Abstract: The present invention relates to a method and device for enhancing coverage of a power-limited mobile terminal by sending information relating to a single Hybrid Automatic Repeat Request (HARQ) process from the mobile terminal to a base station using several transmission time intervals.

Abstract: The invention relates to a receiving unit in a wireless communication network comprising a processing unit being configured to generate Automatic Repeat request (ARQ) feed-back messages for acknowledgement or negative acknowledgement of received data units in a wireless communication channel. In order to avoid signalling overhead, it is proposed that said processing unit is further configured to delay the generation of Automatic Repeat request (ARQ) feedback messages until the processing unit has recognized irregularities in the data transmission or until the number (C) of delayed Automatic Repeat request (ARQ) feedback messages has reached a threshold value.

Abstract: This disclosure describes methods for communicating simultaneously on multiple frequencies. In various implementations, if a wireless terminal receives a first set of data and a second set of data simultaneously on different frequencies, then it sends signals responsive to the first and second sets of data on different slots of a single uplink subframe and on different frequencies.

Abstract: In some aspects, the disclosure is directed to methods and systems for protocol coexistence. Within a frequency band of a wireless local area network (WLAN), a device implemented for operation in at least a non-WLAN protocol can determine that the frequency band is quiet at a first time instance. The device can transmit a message in WLAN protocol responsive to the determination and prior to operation in the non-WLAN protocol within the frequency band. The message can have a receiver address other than an address belonging to other devices operating within the frequency band.

Abstract: A method of transmitting a signal, performed by a base station, in a wireless communication system. The method according to one embodiment includes transmitting a backhaul downlink signal to a relay station through a backhaul downlink transmission subframe. The backhaul downlink transmission subframe includes 14 orthogonal frequency division multiplexing (OFDM) symbols and the 14 OFDM symbols are indexed 0 to 13. An access downlink transmission subframe, used by the relay station to transmit a signal to a user equipment, and the backhaul downlink transmission subframe are transmitted with a time aligned subframe boundary, and OFDM symbols having indices K to 12 are used for transmitting the backhaul downlink signal, where K is a natural number and 1?K?3.

Abstract: In a WLAN, a device sets a first NAV to a bandwidth used by a signal from a second device. The device selects a channel that does not correspond to the bandwidth from among a plurality of channels when a predetermined condition is satisfied. The predetermined condition includes a condition that the first NAV is set. The device transmits a first frame on the selected channel.

Abstract: A device comprises a plurality of distributed transceivers, a plurality of distributed beamformers, a baseband processor, and a network management engine. The distributed transceivers perform beamforming in a radio frequency band. The distributed beamformers, however, performs beamforming in an intermediate frequency band. Each of the distributed transceivers is coupled to a corresponding one of the distributed beamformers. Each transceiver-beamformer pair is coupled to the baseband processor utilizing a same communication medium such as a cable. For transmission, a data stream generated at baseband is converted to intermediate frequencies. With a low-power transmission, the distributed beamformers transmit the data stream wirelessly in the intermediate frequencies to a receiving device. With a normal-power transmission, the distributed transceivers transmit the data stream to the receiving device in the radio frequency band. The transceivers and the beamformers are turned OFF whenever not being used.

Abstract: A method of handling a device-to-device (D2D) signal and a device-to-cellular (D2C) signal for a first communication device comprises communicating with a second communication device according to a D2D communication; communicating with a network according to a D2C communication; and transmitting one of the D2D signal and the D2C signal in a subframe, wherein the D2D signal and the D2C signal are transmitted to the second communication device and the network, respectively.

Abstract: Embodiments of the present invention provide a method and an apparatus for demodulating a physical random access channel signal. The method includes: acquiring a down-sampling sequence of a PRACH demodulation signal, and acquiring a power sequence of the down-sampling sequence; determining a position of a sounding reference signal sampling point in the down-sampling sequence according to the power sequence; and eliminating the sounding reference signal sampling point in the down-sampling sequence according to the position of the sounding reference signal sampling point, so as to perform PRACH coherent detection on a down-sampling sequence obtained after the sounding reference signal sampling point is eliminated. In the method and the apparatus for demodulating a physical random access channel signal in the embodiments of the present invention, interference from a sounding reference signal can be restrained and false alarms in PRACH detection can be reduced.

Abstract: The present invention relates to a wireless communication system. A method for user equipment transmitting channel state information (CSI) in the wireless communication system, according to the present invention, comprises the steps of: receiving information on an N number of CSI configurations for reporting the CSI; receiving information for selecting an M (2?M?N) number of the CSI configurations for joint CSI from the N number of the CSI configurations; calculating the M number of rank indexes (RI) based on each channel corresponding to the M number of CSI configurations; calculating a joint RI based on a synthetic channel generated by synthesizing the channels corresponding to the M number of the CSI configurations; and transmitting information on whether to report the joint CSI based on a result from comparing the M number of the RIs and the joint RI.

Abstract: Provided are a method and an apparatus for signal transmission in a wireless communication system. The apparatus comprises: an information processor for generating a first information sequence based on a first transmission symbol and a first resource index, and a second information sequence based on a second transmission symbol and a second resource index; a reference signal generator for generating a different reference signal depending upon whether a first resource block indicated by the first resource index and a second resource block indicated by the second resource index are the same; and an antenna for transmitting a signal generated based on the first information sequence, the second information sequence, and the reference signal sequence.

Abstract: Methods and apparatuses are provided for determining cyclic shift (CS) values and/or orthogonal cover codes (OCC) for a plurality of demodulation reference signals (DM-RS) transmitted over multiple layers in multiple-input multiple-output (MIMO) communications. A CS index can be received from a base station in downlink control information (DCI) or similar signaling. Based at least in part on the CS index, CS values for the plurality of DM-RS can be determined. In addition, OCC can be explicitly signaled or similarly determined from the CS index and/or a configured CS value received from a higher layer. In addition, controlling assignment of CS indices and/or OCC can facilitate providing orthogonality for communications from paired devices in multiuser MIMO.

Abstract: Disclosed is a method for a base station to transmit a downlink control channel in a wireless communication system. Specifically, the method comprises the steps of: separating each resource block, of which there are at least one, into a preconfigured number of subsets; structuring basic resource allocation units for an downlink control channel as one of the subsets comprised in one or more resource blocks; configuring the basic resource allocation units, the number of which correspond to the aggregation level of the downlink control channel, as transmission resources; and using the transmission resource to transmit the downlink control channel to a terminal.

Abstract: Various example embodiments are disclosed herein. According to one example embodiment, a method may include determining, at a base station in a wireless network, an uplink channel quality for a mobile station, sending an acknowledgment/negative acknowledgment (ACK/NAK) aggregation indicator to the mobile station based on the determining, sending a plurality of data bursts to the mobile station, and receiving at least one aggregated ACK/NAK report from the mobile station.

Abstract: A wireless communication device is provided with: a means that, when traffic of said device is greater than another device in a state in which the device is wirelessly connected to a terminal without using CoMP, generates information with which a parameter is altered so that a communication area in which CoMP is used is expanded at the wireless communication device side, said parameter relating to a condition by which the terminal reports a result of a communication measurement between the device and the other device; and a means that carries out an adjustment so that a proportion of resources for communication using CoMP is increased in accordance with the traffic situations of the device and the other device.

Abstract: Various aspects of the disclosure provide a method of operating a user equipment (UE) to determine and report a throughput enhancing channel quality indicator (CQI) value when a physical channel between the UE and a base station is temporally uncorrelated. Reporting such CQI value may maximize the throughput of the channel when it remains temporally uncorrelated. In one aspect of the disclosure, the UE communicates with a base station utilizing a channel and determines that the channel is temporally uncorrelated. The UE further determines a plurality of CQIs in a first CQI reporting mode and computes the respective throughputs of the channel based on the plurality of CQIs. In addition, the UE selects a CQI of the plurality of CQIs corresponding to the highest throughput among the plurality of throughputs, and reports the selected CQI to the base station in a second CQI reporting mode while the channel remains temporally uncorrelated.

Abstract: A method and apparatus is disclosed in which a user equipment (UE) receives and processes control information received on a first channel. In accordance with a particular embodiment, a use equipment (UI) having a user equipment processor coupled with user equipment circuitry includes means for receiving, via the user equipment circuitry, a wireless signal of a control channel; in which the wireless signal includes both (i) an N bit field and (ii) control information, the N bit field having been generated using the control information and having therein an N bit cyclic redundancy check (CRC) calculated using at least an N bit user equipment identity for the UE; and in which the UE further includes means for determining, via the user equipment circuitry, that the N bit CRC is correct using the N bit user equipment identity; and means for processing, via the user equipment circuitry, the control information upon the user equipment circuitry determining that the N bit CRC is correct.

Abstract: A method is provided for decoding data in a wireless access system. A user equipment (UE) receives a higher layer signal including an indication that 256 quadrature amplitude modulation (256 QAM) is to be enabled. The UE further receives, via a physical downlink control channel (PDCCH), downlink control information (DCI) including an index field representing a modulation and coding scheme (MCS). The UE also receives data via a physical downlink shared channel (PDSCH) scheduled by the PDCCH, and decodes the received data using the MCS represented by the index field. The UE has a first MCS index table supporting up to 64 quadrature amplitude modulation (64 QAM) and a second MCS index table supporting up to the 256 QAM.

Abstract: Embodiments of the present invention provide a method, a base station, and a user equipment for activating or deactivating a carrier. The method includes the following: A base station determines to activate or deactivate at least one secondary carrier used to communication with a user equipment and transmits a High Speed Shared Control Channel HS-SCCH order to the user equipment, where the HS-SCCH order carries indication information used to indicate activation or deactivation of the at least one secondary carrier. In the embodiments of the present invention, a user equipment is capable of correctly activating or deactivating a carrier.

Abstract: Methods, systems, and devices are described for implementing timing advances in which a propagation delay may exceed a time period of a portion of a radio frame. In some examples, a transmitter may identify a timing advance indicating a time to initiate wireless uplink transmission of a subframe. Such a timing advance may compensate for a propagation delay between the transmitter and a receiver of the wireless uplink transmission. The timing advance may be applied as an integer component and a fractional component in relation to a duration of the subframe, to adjust the time to initiate the wireless uplink transmission of the subframe. The integer component may be used to adjust one or more subframe characteristics, and the fractional component that may be used to adjust the time to initiate the wireless uplink transmission of the subframe.

Abstract: The present invention discloses a method for scheduling user equipment on a full-duplex cellular network, including: determining a pairing set for each piece of user equipment in a cell, where a pairing parameter of the piece of user equipment and any piece of user equipment that is in the pairing set of the piece of user equipment meets a preset threshold; and selecting, when a piece of user equipment is scheduled to perform data transmission, another piece of user equipment from a pairing set of the piece of user equipment to perform data transmission in an opposite direction. Embodiments of the present invention further provide a corresponding apparatus. According to the technical solution of the present invention, existing spectrum resources can be utilized more thoroughly and spectrum utilization efficiency of wireless access can be improved.

Abstract: In accordance with an example embodiment of the present invention, an apparatus, comprising at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following: deciding to switch to a half-duplex mode of operations upon detecting a triggering condition including that multiple radio stacks are activated at the apparatus simultaneously; signaling an associated base station the decision of switching to the half-duplex mode half-duplex mode; and entering the half-duplex mode of operation, is disclosed.

Abstract: A method and apparatus are provided for signal transmission and reception in a Time Division Duplex (TDD) system. The method includes receiving, from a base station, first configuration information including an uplink reference Uplink-Downlink (UL-DL) configuration; receiving, from the base station, second configuration information including a downlink reference UL-DL configuration; receiving, from the base station, third configuration information including an equivalent UL-DL configuration based on the first configuration information and the second configuration information; and communicating signals with the base station based on the third configuration information.

Abstract: A dual path source synchronous interface is disclosed. In one embodiment, a source synchronous interface includes a transmitter coupled to serially receive data from a first functional circuit block, and a receiver coupled to provide data serially to a second functional circuit block. Data is conveyed to the transmitter on a single signal line, and similarly, from the receiver on another single signal line. The transmitter is coupled to the receiver by two signal lines. The serial data received by the transmitter may be separated into two streams of alternating bits, e.g., a first bit is transmitted on one signal line, the next bit is transmitted on the other signal line, and so forth. At the receiver, the alternating bit streams may be re-combined into a single bit stream for transfer to the second functional circuit.

Abstract: System, method and computer program product for setting phase control codes to (in-phase) I and (quadrature) Q rotators to a first code pair, different by enough to produce a phase difference between the rotator outputs sufficient to be detected with minimal error by a phase-to-voltage converter. Auxiliary trim DACs are then adjusted according to calibration logic until a comparator output detects a phase difference between the I and Q rotators are within tolerable limits. The resulting trim codes are stored for both the codes in the pair. These trim codes along with the main codes are subsequently applied whenever the codes are used thereafter. These steps are repeated with each successive code pair having the same separation as the first code pair, e.g. both incremented by same amount until all codes have been calibrated. In this manner having the phase separation between all code pairs forced to the same value.

Abstract: A half-rate clock data recovery circuit includes: a voltage-controlled oscillator (VCO) for generating a data sampling clock and an edge sampling clock according to a control voltage; an adjusting circuit for dynamically controlling the VCO to adjust the phase difference between the data sampling clock and the edge sampling clock to be different from 90 degrees in multiple test periods; and a control circuit for instructing the adjusting circuit to respectively utilize different control value combinations to control the VCO in the multiple test periods, and for recording multiple recovered-signal quality indicators respectively corresponding to the multiple test periods. Afterwards, the control circuit instructs the adjusting circuit to utilize a control value combination corresponding to the best quality indicator among the multiple recovered-signal quality indicators to control the VCO.

Abstract: An example clock delivery system includes a phase-locked loop (PLL) configured to generate a plurality of input clocks, a phase interpolator configured to receive the plurality of input clocks and generate a plurality of output clocks, and a clock data recovery (CDR) circuit configured to receive the plurality of output clocks. The phase interpolator includes a decoder having a plurality of inputs configured to receive binary codes and a respective plurality of outputs configured to output thermometer codes, and a mixer circuitry segmented into a plurality of unit circuits that are enabled or disabled based on bits of the thermometer codes.

Abstract: A phase to digital converter determines whether a phase of an internal clock advances or delays with respect to an input serial signal and outputs a first determination code, a determination circuit outputs, for each of first periods, a second determination code based on a plurality of the first determination codes, a gain control code generator circuit generates a gain control code based on a total sum of the first determination codes during the first period, and a phase adjustment code generator circuit gives a gain in accordance with the gain control code to the second determination code, and generates and outputs a phase adjustment code so that the phase of the internal clock is adjusted to make the phase of the internal clock follow the input serial signal.

Abstract: Voltage mode drivers and an electronic apparatus having the same are provided. The voltage mode drivers may include a voltage regulator and a ripple compensation unit connected to an output terminal of the voltage regulator and configured to compare a current data bit of a data pattern with a previous data bit of the data pattern in synchronization with a clock signal input into the ripple compensation unit, generate a control signal when the current data bit is equal to the previous data bit, and apply a ground voltage to the output terminal in response to the control signal.

Abstract: Systems and techniques for securing accessible computer-executable program code and systems are provided. One or more base functions may be generated and blended with existing program code, such that it may be difficult or impossible for a potential attacker to distinguish the base functions from the existing code. The systems and code also may be protected using a variety of other blending and protection techniques, such as fractures, variable dependent coding, dynamic data mangling, and cross-linking, which may be used individually or in combination, and/or may be blended with the base functions.

Abstract: The invention relates to a method for creating a set of asymmetrical cryptographic key pairs, wherein the set of key pairs has a first key pair (K1) and a second key pair (K2), wherein the first key pair is formed by a first private (G1) and a first public key (O1) and the second key pair is formed by a second private (G2) and a second public key (O2), wherein a first cipher (C_G2_O1) is allocated to the first and second key pair, wherein the first cipher is formed by an encryption of the second private key (G2) with the first public key (O1), having the following steps: adding a third asymmetrical cryptographic key pair (K3) to the set of key pairs, wherein the third key pair is formed by a third private (G3) and a third public key (O3); creating a second cipher (C_G3_O1) by encrypting the third private key (G3) with the first public key (O1); storing the second cipher (212; 186), wherein the set of key pairs has a directed graph structure.

Abstract: There is provided a method and apparatus for resetting a password for a device or managing the device, the device having an encryption perimeter. A device shares a public/private key pair with a server, the public key being on the device and the private key being on the server. An intermediate value is encrypted on the mobile device using the public key. If the password is lost or the device needs to be managed, the server can request the encrypted intermediate value, decrypt it, and send the decrypted value to the mobile device which may then resume operations. A new password may be provided by the server or the user may set a new password once the encryption key is recreated from the decrypted intermediate value.

Abstract: A pool of public keys, having a pool size, is received from a first device. The pool size reflects a target number of keys to be included in the pool. One of the received public keys included in the pool of keys is designated as a reserve key. A public key is selected from the pool of received public keys for use in conjunction with encrypting a communication to the first device. The selecting includes preferentially selecting a public key that is not designated as a reserve key, if at least one such key is present in the pool in addition to the reserve key. The size of the pool can be dynamically adjusted.

Abstract: An input unit inputs a predicate which describes a plurality of selected elements being elements selected by a user. A predicate generation unit extracts two or more than two selected elements that are dependent on the same element in a higher layer, from the plurality of selected elements described in the predicate. Furthermore, the predicate generation unit reduces the number of elements described in the predicate by replacing a description of the two or more than two selected elements extracted with a description of the element in the higher layer.