Methods and apparatus for performing handoffs in a multi-carrier wireless communications system
First Claim
1. A method of operating a mobile communications device to implement a handoff of a mobile communications device between a first network attachment point and a second network attachment point, said mobile communications device having a first wireless communications link with the first network attachment point at the time said handoff is initiated, said first wireless communication link using signals in a first frequency band, the method comprising:
- communicating to said second network attachment point, via a first signal communicated over said first wireless communications link, an intent to initiate a handoff to said second network attachment point, wherein said first communications link corresponds to a first frequency band and said second communications link corresponds to a second frequency band which does not use frequencies in said first communications band;
receiving, via said first wireless communications link, information indicating a dedicated air link resource assigned to said mobile device by said second network attachment point to be used in communicating with said second network attachment point over a second frequency band which is different from said first frequency band;
terminating said first wireless communications link;
using said dedicated communications resource to transmit a signal over the air in said second frequency band to establish a second wireless communications link with said second network attachment point;
determining second network attachment point timing information from a transmitter information signal transmitted by said second network attachment point into said first frequency band; and
wherein said terminating of said first communications link is performed at a time determined by said mobile communications device as a function of the time said transmitter information signal was received from said second network attachment pointdetermining from said beacon signal at least one of a cell identifier and a sector identifier; and
determining, from stored information corresponding to the determined cell or sector identifier information, information about the structure of a communications segment used for registration signaling at the second network attachment point, wherein said information about the structure of a communication segment includes information about tones in said segment which are to be used on a contention free basis for mobile device registration signaling, wherein said dedicated resource assigned to said mobile node is a set of tones in an uplink communications segment, said mobile communications device identifying the set of tones from information received from said second network point of attachment via said communications link and form said information about the structure of a communication segment.
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Accused Products
Abstract
A mobile communications device initiates a handoff from its current base station (BS) sector network attachment point to a new BS sector. The mobile sends a handoff request over its current wireless link to the current BS sector, which forwards the request to the new BS sector, e.g., via a network link. The new BS sector processes the request assigning dedicated resources, e.g., an identifier and dedicated uplink segments. Information identifying the allocated resources is conveyed from the new BS sector via the current BS sector to the mobile. The mobile determines the time of the allocated dedicated segments based upon a received beacon signal from the new BS sector with known timing relationships to dedicated segments. The mobile breaks the original wireless link just prior to the time of the first assigned dedicated segment. The mobile communicates information on the assigned dedicated segments to perform registration operations, e.g., timing synchronization and power control, establishing a new wireless link.
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Citations
26 Claims
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1. A method of operating a mobile communications device to implement a handoff of a mobile communications device between a first network attachment point and a second network attachment point, said mobile communications device having a first wireless communications link with the first network attachment point at the time said handoff is initiated, said first wireless communication link using signals in a first frequency band, the method comprising:
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communicating to said second network attachment point, via a first signal communicated over said first wireless communications link, an intent to initiate a handoff to said second network attachment point, wherein said first communications link corresponds to a first frequency band and said second communications link corresponds to a second frequency band which does not use frequencies in said first communications band; receiving, via said first wireless communications link, information indicating a dedicated air link resource assigned to said mobile device by said second network attachment point to be used in communicating with said second network attachment point over a second frequency band which is different from said first frequency band; terminating said first wireless communications link; using said dedicated communications resource to transmit a signal over the air in said second frequency band to establish a second wireless communications link with said second network attachment point; determining second network attachment point timing information from a transmitter information signal transmitted by said second network attachment point into said first frequency band; and
wherein said terminating of said first communications link is performed at a time determined by said mobile communications device as a function of the time said transmitter information signal was received from said second network attachment pointdetermining from said beacon signal at least one of a cell identifier and a sector identifier; and determining, from stored information corresponding to the determined cell or sector identifier information, information about the structure of a communications segment used for registration signaling at the second network attachment point, wherein said information about the structure of a communication segment includes information about tones in said segment which are to be used on a contention free basis for mobile device registration signaling, wherein said dedicated resource assigned to said mobile node is a set of tones in an uplink communications segment, said mobile communications device identifying the set of tones from information received from said second network point of attachment via said communications link and form said information about the structure of a communication segment. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A mobile node for use in a communication system including a first network point of attachment which uses a first frequency band to receive user data and a second network attachment point which uses a second frequency band which is different from said first frequency band to receive user data, said mobile node comprising:
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means for initiating a handoff from said first network attachment point to said second network attachment point by communicating a signal indicating an intent to handoff to the second network attachment point transmitted in the first frequency band over a wireless communications link with said first network attachment point; means for receiving from said second network attachment point, via a second signal communicated via said first link information indicating a resource dedicated to said mobile device by said second network attachment point to be used in communicating with said second network attachment point, wherein said indicated dedicated resource is an uplink channel segment dedicated to said mobile node for use in performing at least one of registration signaling, timing control signaling and power control signaling; means for terminating said first communications link; means for transmitting a signal in said second frequency band using said dedicated communications resource to establish a second wireless communications link with said second network attachment point; means for detecting a beacon signal used to communicate transmitter information from said second network access point; stored information about the structure of uplink communications channels for a plurality of different base station sectors, said stored information including information about the timing between beacon signals transmitted from said base station sectors and access segments to be used for registration in said base station sectors; and means for performing contention based registration signaling with said second network access point if the second communications link is not successfully established through the use of said dedicated resource, wherein said stored information further includes information about tones assigned to devices identified by different wireless terminal identifiers that are assigned by said second network access point. - View Dependent Claims (18, 19, 20)
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21. A method of implementing a mobile node handoff between a first wireless communications link with a first base station sector, said first wireless communications link using a first carrier, and a second wireless communications link with a second base station sector said second wireless communications link using a second carrier, at least the first sector being different from the second sector or the first carrier being different from the second carrier, the method comprising:
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operating said mobile node to receive a timing correction signal over said first wireless communications link; operating said mobile node to make a transmission timing adjustment to adjusting the timing of signals transmitted by said mobile node over the first wireless communications link; operating the mobile node to send a signal over said first wireless communications link indicating an intent to handoff to said second wireless communications link; operating the mobile node to receive over said first wireless communications link information indicating a dedicated resource to be used by said mobile when communicating over said second wireless communications link, wherein said dedicated resource is a dedicated airlink communications segment to be used in establishing communications with said second base station sector when transmitting signals over the air to said second base station sector using said second carrier frequency to establish said second wireless communications link, wherein said first and second base station sectors are different sectors within the same cell; operating the mobile node to terminate said first wireless communications link; operating the mobile node to transmit at least one of user data and a non-timing control signal over said second wireless communications link prior to making a transmission timing control adjustment based on a timing control signal received over said second wireless communications link; operating a second sector control module to; allocate said dedicated resource; and communicate information about said dedicated resource to said first sector for transmission to said mobile node; and operating said first sector to transmit an IP routing update signal to trigger redirection of IP packets directed to said mobile node, to said second sector prior to said mobile node being able to receive or transmit user data over said second wireless communications link. - View Dependent Claims (22, 23, 24, 25, 26)
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Specification