Kazuhiro Okanoue

Bio: Kazuhiro Okanoue is an academic researcher from NEC. The author has contributed to research in topics: Terminal (electronics) & Communications system. The author has an hindex of 23, co-authored 114 publications receiving 1795 citations.

Method of setting up AD HOC local area network, method of communicating using said network, and terminal for use with said network

Abstract: An ad hoc LAN is set up in an environment in which there simultaneously exist a backbone-connected LAN connected by a high-speed backbone network and an ad hoc LAN not connected to the backbone network, wherein the ad hoc LAN is capable of communicating simultaneously with both LANs. An ad hoc LAN is defined as one multicast group used within the backbone network and backbone-connected LAN. This makes it possible for a terminal, which is connected to the ad hoc LAN and backbone-connected LAN simultaneously so that it may communicate with both LANs, to participate in the ad hoc LAN in the same manner as it would participate in a multicast group of a conventional backbone-connected LAN. As a result, the terminal construction is simplified and the terminal can be connected to an ad hoc LAN and backbone-connected LAN simultaneously.

System for location multicasting and database management for mobile sessions in any computer subnetworks without using a home router of a home subnetwork

Abstract: In a computer network where each mobile host is assigned a subnetwork-independent logical identifier (L-ID), the mobile host acquires a subnetwork-dependent geographical identifier (G-ID) from an agent-existing subnetwork and sends the G-ID to the home subnetwork of the mobile host for location registration if a beacon received therefrom is a first one or different from a previous one or acquires a G-ID from an agentless subnetwork and sends the G-ID to the home subnetwork if no beacons are received. At intervals, a multicast packet is sent from the mobile host, containing the acquired G-ID to the agentless subnetwork. A similar multicast packet is received from a second mobile host and the G-ID contained therein is stored in a database corresponding to the L-ID of the second mobile host. When establishing a session, a data packet is sent from the mobile host to the network along with a G-ID corresponding to a L-ID of the data packet stored in the database. No G-ID is appended if the L-ID of the data packet has no corresponding identifier in the database. At the home subnetwork, a data packet destined to a mobile host of a subnetwork is encapsulated with the G-ID of the mobile host and routed to the subnetwork.

Noise-immune space diversity receiver

Abstract: In a space diversity receiver, matched filters and a like number of channel estimators are respectively coupled to diversity antennas to receive sequentially coded symbol sequences. A branch metric calculator receives the outputs of the matched filters and the estimates from the channel estimators to calculate a branch metric of the received sequences for coupling to a maximum likelihood (ML) estimator. The branch metric is obtained by summing branch metric coefficients derived from channel estimates respectively with the output of the matched filters or by summing branch metric coefficients derived from a vector sum of channel estimates with the matched filter outputs. In another embodiment, adaptive channel estimators are provided for deriving channel estimates from received sequences and the output of an ML estimator. First branch metrics are derived from the received sequences and supplied to a branch metric quality estimator in which quality estimates of the channels are derived from the first branch metrics. An evaluation circuit evaluates the first branch metrics according to the quality estimates and produces a second branch metric for coupling to the ML estimator.

Signal reproducing apparatus for optical recording and reproducing equipment with compensation of crosstalk from nearby tracks and method for the same

Abstract: An apparatus and a method for reproducing a signal, free of cross-talk and intersymbol interference, from an optical recording medium. The signal reproducing apparatus and method is for use in combination with an optical source for emitting a plurality of light beams directed to a center track, which contains the information to be reproduced, and the tracks adjacent to the center track on a recording medium. The signals received from the reflections of the light beams from the adjacent tracks are processed by a frequency characteristic converter and then added to the signal from the center track to eliminate the cross-talk in the signal from the center track created by the signals from the adjacent tracks.

Ad hoc network of mobile hosts using link table for identifying wireless links and destination addresses

Abstract: In an ad hoc network of mobile hosts interconnectable by a number of wireless links, each mobile host includes a link table having a multiple entries each comprising a host name, a link identifier indicating one of the wireless links, a network layer address and a data link layer address. Each of the mobile hosts comprises a link table having a plurality of entries each comprising a host name, a link identifier indicating one of the wireless links, a network layer address and a data link layer address. Each mobile host is responsive to an entered destination host name for making a search through the link table, transmitting a frame containing the network layer and data link layer addresses of an entry of the link table on one of the wireless links which is indicated by the link identifier of this entry if this entry contains the destination host name. If the link table does not contain the destination host name, the mobile host scans the wireless links, broadcasts a link table request message on one of the scanned wireless links, receives a remote link table containing the destination host name, and transmits a frame containing network layer and data link layer addresses of the received link table on the wireless link on which the remote link table was received.

System and method for monitoring and controlling remote devices

Abstract: The present invention is generally directed to a system for monitoring a variety of environmental and/or other conditions within a defined remotely located region. In one aspect, a system is configured to monitor utility meters (613) in a defined area. The system is implemented by using a plurality of wireless transmitters (614), each integrated into a sensor (612) adapted to monitor a particular data input. The system also includes a plurality of transceivers (221) that are dispersed throughout the region at defined locations. The system uses a local gateway (210) to translate and transfer information from the transmitters to a dedicated computer (260) on a network (230). The dedicated computer collects, compiles and stores the data for retrieval upon client demand across the network. The computer further includes means for evaluating the received information and identifying an appropriate control signal to be applied at a designated actuator.

Maximum ratio transmission

Abstract: This paper presents the concept, principles, and analysis of maximum ratio transmission for wireless communications where multiple antennas are used for both transmission and reception. The principles and analysis are applicable to general cases, including maximum ratio combining. Simulation results agree with the analysis. The analysis shows that the average overall SNR is proportional to the cross-correlation between channel vectors and that error probability decreases inversely with the (L/spl times/K)th power of the average SNR.

System and method for management of a shared frequency band

Abstract: A system, method, software and related functions are provided for managing activity in a radio frequency band that is shared, both in frequency and time, by signals of multiple types. An example of such a frequency band is an unlicensed frequency band. Radio frequency energy in the frequency band is captured at one or more devices and/or locations in a region where activity in the frequency band is happening. Signals occurring in the frequency band are detected by sampling part or the entire frequency band for time intervals. Signal pulse energy in the band is detected and is used to classify signals according to signal type. Using knowledge of the types of signals occurring in the frequency band and other spectrum activity related statistics (referred to as spectrum intelligence), actions can be taken in a device or network of devices to avoid interfering with other signals, and in general to optimize simultaneous use of the frequency band with the other signals. The spectrum intelligence may be used to suggest actions to a device user or network administrator, or to automatically invoke actions in a device or network of devices to maintain desirable performance.

A system and method for routing 802.11 data traffic across channels to increase ad-hoc network capacity

Abstract: A system and method for data transmission incorporating a channel bridge node (102-6) which can identify and deliver data traffic requiring delivery via alternate 802.11 data channels (Fig.4). The system and method provides a channel bridging node which is configured to communicate via each channel of the available spectrum in series. The node advertises this capability and accepts data traffic for communication over any number of channels. Data is buffered for subsequent delivery once the node is configured to communicate via the channel to which the data is addressed. In doing so, the system and method provides a channel bridge which enables routing of 802.11 data traffic across channels in 802.11 ad-hoc networks, thus increasing ad-hoc network capacity.

Ad hoc network discovery menu

Abstract: When an ad hoc network is formed between short range wireless devices, at least one device assumes the role of an ad hoc network information provider for the new piconet. In this role, the device allocates a browsing hierarchy of service classes in its service registry. The service classes will provide a record to characterize the ad hoc network. When a new wireless device arrives within the communication range of any member of the ad hoc network, its inquiry signals are answered by the first member detecting the inquiry. If that first member is an ad hoc network information provider, it responds with information accessed from its service registry characterizing the ad hoc network. If, instead, an ordinary device in the ad hoc network is the first to respond to the inquiry signals of the arriving device, the device responds with the address of the ad hoc network information provider. The arriving device then pages the ad hoc network information provider to obtain information characterizing the ad hoc network.