摘要:
A broadband powerline communication system makes use of knowledge of the spectrum characteristics of a local radio environment in order to improve system performance. A determination is made of the spectrum characteristics of a radio environment in the vicinity of the broadband powerline communication system that is transmitting data on modulated carrier frequencies. In order to avoid interference, certain ones of the carrier frequencies otherwise used by the broadband powerline communication system may be selectively masked based on the determination. The spectrum characteristics may be determined 1) in advance and used to compile a configuration database comprising frequency masking parameters; 2) by monitoring the local radio environment using the transmitter/receiver nodes of the system; or 3) based upon receipt of an indication from a conflicting user that the user is experiencing interference. Various combinations of these spectrum characteristic determination techniques may also be used.
摘要:
Disclosed is a power line broadband communication system having broadband coupler devices capable of direct electrical connection to an energized power line. The coupler includes a conductive portion movable by an adjustable member from a non-conducting retracted position spaced apart from the power transmission line to a forward conducting position in electrical contact with the power line. An insulated arm supports the coupler on the power line. A base on the coupler is engageable with a remotely activated tool in order to accomplish the electrical connection in a safe and secure manner. Broadband data signals are sent to and from customer premises along the shared energized power lines. New coupler connections to the energized power lines allow the additional broadband customers and/or repeaters to join the communication system. Also couplers may provide connections to control electronics, routers, wireless transceivers, and may allow the broadband signals to bypass transformers on the power lines. The invention helps to minimize risk by allowing an installer to be remotely spaced from the energized power line while making the electrical coupling contact with the energized power line.
摘要:
Disclosed is a power line broadband communication system having broadband coupler devices capable of direct electrical connection to an energized power line. The coupler includes a conductive portion movable by an adjustable member from a non-conducting retracted position spaced apart from the power transmission line to a forward conducting position in electrical contact with the power line. An insulated arm supports the coupler on the power line. A base on the coupler is engageable with a remotely activated tool in order to accomplish the electrical connection in a safe and secure manner. Broadband data signals are sent to and from customer premises along the shared energized power lines. New coupler connections to the energized power lines allow the additional broadband customers and/or repeaters to join the communication system. Also couplers may provide connections to control electronics, routers, wireless transceivers, and may allow the broadband signals to bypass transformers on the power lines. The invention helps to minimize risk by allowing an installer to be remotely spaced from the energized power line while making the electrical coupling contact with the energized power line.
摘要:
A method and computer readable medium for encoding data onto a channel broadcasting a program are disclosed. For example, the method selects a channel that is being used to broadcast a program, generates data having characteristics in accordance with an error burst signature and transmits the data on the channel that is being used to broadcast the program.
摘要:
A method and system for preventing packet loss during handoff of a mobile host between access networks. In accordance with an aspect of the invention, a home agent on a network maintains a FIFO (First In-First Out) buffer for every mobile host that it serves. When a packet destined for a particular mobile host is received at the home agent, it is assigned an incremental sequence number, encapsulated as an IP packet, and forwarded to the mobile host with the sequence number as an identifier. The packet and sequence number are thereafter stored in the buffer for a period of time after the packet was forwarded to the mobile host. After hand-off to the arriving network is completed, the mobile host sends the sequence number of the last-received IP packet to the home agent and the new care-of IP address. Using this sequence number, the home agent then determines whether any incoming packets had been routed to the previous care-of IP address. These are retrieved from the buffer, and resent to the new care-of IP address.
摘要:
An IP-based corporate network architecture and method for providing seamless secure mobile networking across office WLAN, home WLAN, public WLAN, and 2.5 G/3 G cellular networks for corporate wireless data users. The system includes Internet roaming clients (IRCs), a secure mobility gateway (SMG), optional secure IP access (SIA) gateways, and a virtual single account (VSA) server. The IRC is a special client tool installed on a mobile computer (laptop or PDA) equipped with a WLAN adaptor and a cellular modem. It is responsible for establishing and maintaining a mobile IPsec tunnel between the mobile computer and a corporate intranet. The SMG is a mobile IPsec gateway installed between the corporate intranet and the Internet. It works in conjunction with the IRC to maintain the mobile IPsec tunnel when the mobile computer is connected on the Internet via a home WLAN, a public WLAN, or a cellular network. The SIA gateway is a special IPsec gateway installed in the middle of the wired corporate intranet and an office WLAN. It works with the IRC to ensure data security and efficient use of corporate IP addresses when the mobile computer is connected to the office WLAN. The VSA server manages authentication credentials for every corporate user based on a virtual single account concept. The Internet Roaming system can provide secure, always-on office network connectivity for corporate users no matter where they are located using best available wireless networks.
摘要:
A method and apparatus to enable IP networking for mobile hosts without requiring changes to be made to the TCP/IP stack in the operating system installed on the mobile hosts. The apparatus is an “intelligent device” that can be installed on or connected to a mobile host, and may comprise a software-only logical module, physical hardware, or a combination of both. To a mobile host, the intelligent device emulates a network interface such as an Ethernet card or a telephone modem. The intelligent device appears to an access network just like any regular IP host connected to the access network through a physical network interface device. The intelligent device handles all mobile networking functions for the mobile host, and may control multiple different physical network interface devices to enable a connection to the “best” access network available to the mobile user at his location.
摘要:
An access interface module includes a first network interface module for interfacing with a first access network and a second network interface module for interfacing with a second access network of a type that is different from the first network. The access module can further include a processor coupled to the first and second network interface modules and a device interface module coupled to the processor for interfacing with a host device.
摘要:
A network interface driver embodied in a processor readable medium comprising executable program instructions that, when executed by a processor, independently process internetworking protocols for a host computer (or other network access device) with another computer on a remote network. The driver appears to the operating system as a regular network interface driver, but it can support enhanced kernel-level internetworking protocols by using a state machine to generate, drop, and change incoming and outgoing IP packets in a manner transparent to the operating system.
摘要:
A fast authentication and access control method of authenticating a network access device to a communications network having an access point communicating with a remote authentication (home AAA) server for the network access device. The method includes the step of receiving an access request having an authentication credential from the network access device at the access point. The authentication credential includes a security certificate having a public key for the network access device and an expiration time. The security certificate is signed with a private key for the remote authentication server. The access point locally validates the authentication credential by accessing the public key of the remote authentication server from a local database, and checking the signature and expiration time of the security certificate. If the authentication credential is validated at the access point, the access point grants the network access device conditional access to the network by sending an access granted message to the network access device. The access granted message includes a session key encrypted with a public key for the network access device. The session key is stored in a database associated with the access point. The access point contacts the remote authentication server to check a revocation status of the security certificate for the network access device. If the access point receives a message from the remote authentication server that the authentication credential for the network access device has been revoked, it suspends network access for the network access device.