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公开(公告)号：CA2330780A1
公开(公告)日：2001-08-09
申请号：CA2330780
申请日：2001-01-10
Applicant: LUCENT TECHNOLOGIES INC
Inventor： VANDERVEEN MICHAELA C , DAVIES STEPHEN WILLIAM
Abstract: The penalties associated with relying on layer-4 to handle packets lost as a result of a handoff can be reduced by forwarding, in response to a handoff request from a first base station to a second base station, at least one layer-2 fra me of a layer-3 packet destined to/from the wireless terminal that has been passed down from layer-3 to layer-2, and so is indicated to have been transmitted at lay er- 3 even though not all of the layer-2 frames of the layer-3 packet have actually bee n transmitted. In one embodiment of the invention, each of the at least one layer-2 frames may be encapsulated together in a special layer-3 packet that is transferred from the first base to the second base station in the usual manner of inter- base- station communication. Advantageously, packets are not lost at layer-4 due t o handoffs. Thus, layer-4 retransmissions are not required, and so delays in t he network are reduced. Furthermore, if only the layer-2 frames that were not transmitted over the air to the wireless terminal by the first base station are transferred to the second base station, a savings may be had in use of the a ir interface.
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公开(公告)号：CA2330709A1
公开(公告)日：2001-08-09
申请号：CA2330709
申请日：2001-01-10
Applicant: LUCENT TECHNOLOGIES INC
Inventor： VANDERVEEN MICHAELA C , DAVIES STEPHEN WILLIAM
Abstract: At least portions of the map of the base stations, i.e., which base stations are neighbors, is discovered and updated using a wireless terminal controlled handoff process. The portion of the map that is discovered by a particular base station is typically its neighbors to which it can possibly hand off a call it is serving. It tak es at least one handoff with each such base station neighbor for the particular base station to discover its entire local map, i.e., all the base stations to which the particular base station can perform handoffs. The wireless terminal handoff process is used to supply a base station with information about other base stations with whom the base station can coopera te to perform handoffs. The handoff process may subsequently be performed more expeditiously between the particular base station and such other base statio ns using the obtained information. As part of the handoff process, the wireless terminal tells the new base station to which it is handing off the call the identity of the previou s base station from which control is being handed off. The wireless terminal then completes handoff and begins to be served by the new base station. If the new base station doe s not have a valid record for the previous base station, it forms a trust relationship wi th the previous base station and creates a record for it, thus identifying it as a neighbor to which it can perform expedited handoff in response to the control of a wireless terminal.
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公开(公告)号：BR0100224B1
公开(公告)日：2014-08-19
申请号：BR0100224
申请日：2001-01-31
Applicant: LUCENT TECHNOLOGIES INC
Inventor： DAVIES STEPHEN WILLIAM , VANDERVEEN MICHAELA C
Abstract: The penalties associated with relying on layer-4 to handle packets lost as a result of a handoff can be reduced by forwarding, in response to a handoff request from a first base station to a second base station, at least one layer-2 frame of a layer-3 packet destined to/from the wireless terminal that has been passed down from layer-3 to layer-2, and so is indicated to have been transmitted at layer-3 even though not all of the layer-2 frames of the layer-3 packet have actually been transmitted. In one embodiment of the invention, each of the at least one layer-2 frames may be encapsulated together in a special layer-3 packet that is transferred from the first base to the second base station in the usual manner of inter-base-station communication. Advantageously, packets are not lost at layer-4 due to handoffs. Thus, layer-4 retransmissions are not required, and so delays in the network are reduced. Furthermore, if only the layer-2 frames that were not transmitted over the air to the wireless terminal by the first base station are transferred to the second base station, a savings may be had in use of the air interface.
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公开(公告)号：DE60142000D1
公开(公告)日：2010-06-17
申请号：DE60142000
申请日：2001-01-29
Applicant: LUCENT TECHNOLOGIES INC
Inventor： DAVIES STEPHEN WILLIAM , VANDERVEEN MICHAELA C
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公开(公告)号：CA2298360C
公开(公告)日：2005-08-16
申请号：CA2298360
申请日：2000-02-11
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LAROIA RAJIV , VANDERVEEN MICHAELA C , LI JUNYI
Abstract: In an orthogonal frequency division multiplexing (OFDM) based spread spectr um multiple access system the entire bandwidth is divided into orthogonal tones , and all of the orthogonal tones are reused in each cell. To reduce peak-to-average rati o at the mobile transmitter, each voice user is allocated preferably a single one, bu t no more than a very small number, of the orthogonal tones for use in communicating with t he base station. Data users are similarly allocated tones for data communication, however, the number of tones assigned for each particular data user is a function of the data rate for that user. The tone assignment for a given user is not always the same withi n the available band, but instead the tones assigned to each user are hopped over time. More specifically, in the downlink, the tones assigned to each user are change relatively rapidly, e.g., from symbol to symbol, i.e., the user fast "hops" from one to ne to another. However, in the uplink, preferably slow hopping is employed to allow efficie nt modulation of the uplink signal which necessitates the employing of addition al techniques, such as interleaving, to compensate for the reduction in the intercell interference averaging effect. For data communication power control is employed in the uplink and/or downlink so that the transmission rate is increased, e.g., by increasing the number of symbols transmitted per tone per unit time or the coding rate, as a function of allocated power per tone and the corresponding channel attenuation.
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Patent Agency Ranking
公开(公告)号：CA2298361C
公开(公告)日：2005-06-07
申请号：CA2298361
申请日：2000-02-11
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LAROIA RAJIV , VANDERVEEN MICHAELA C , LI JUNYI
Abstract: An orthogonal frequency division multiplexing (OFDM) based spread spectr um multiple access system using offsetting between cells, and in particular, th e use of tone offsetting and time offsetting, is disclosed. More specifically, frequencies that define the tone set of one cell is offset from the frequencies that define the tone set of at least one adjacent cell. In other words, if a first base station is using tones F1, F2 , ..., F N within a frequency band, then a second base station adjacent to the first base statio n uses tones F1+.DELTA.f, F2+.DELTA.f ..., F N+.DELTA.f within the same frequency band. Furthermore, the symbol timing of the base-station of one cell may be offset from the symbol timing of the base-station of an adjacent cell. Thus, if a first base station starts successive symbols at times T1, T2, and T3, then a second base station adjacent to the first base station starts its respective corresponding successive symbols at times T1+.DELTA.t, T2+.DELTA.t, and T3+.DELTA.t. For example, in a cellular system with hexagonally shaped cells, the tone sets of two adjacent cells are offset by 1/3 of the spacing between adjacent tones, and the symbol timings of two adjacent cells are offset by 1/3 of a symbol period. Advantageously, the intercell interference is more uniformly distributed among users in a cell.
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公开(公告)号：CA2330778C
公开(公告)日：2004-09-21
申请号：CA2330778
申请日：2001-01-12
Applicant: LUCENT TECHNOLOGIES INC
Inventor： DAVIES STEPHEN WILLIAM , VANDERVEEN MICHAELA C
Abstract: The defined boundaries in a network are pushed down to the base station leve l. Doing so necessitates authentication each time a wireless terminal switche s communication, or "handoffs" from one base station to another. To achieve su ch authentication in an efficient manner, security information, i.e., the deriv ed information, is transferred from one base station directly to another. By directly it is meant without accessing any other source of the derived information, although the information may be transferred via other intervening nodes of the network that form an interconnection path for the base stations. A simplified network, i.e., a network with reduced hierarchy from a control point of view, e.g., one that only requires home location register a nd base station network entities along with interconnection therefore, may be employed with a minimal decrease in performance, e.g., a minimal increase in delay, during the hando ff process. In one embodiment of the invention, a first base station which initially receiv es a service request from a wireless terminal requests authentication information from a central security node and receives in response at least, one, but typically two or more, sets of security information. When it is time for a handoff from the first base station to a second base station, the first base station transmits to the second base station at least one of the sets of security information it received from the central security node. The second base station then uses the information it received from the first base station to authenticate the wireless terminal.
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公开(公告)号：AU776701B2
公开(公告)日：2004-09-16
申请号：AU1676801
申请日：2001-02-01
Applicant: LUCENT TECHNOLOGIES INC
Inventor： DAVIES STEPHEN WILLIAM , VANDERVEEN MICHAELA C
Abstract: Paging areas aligned with wireless terminals are dynamically created. A first base station passes to the wireless terminal a list of all the base stations that it knows and are within a prescribed number of handoffs of the first base station. The wireless terminal uses this list to define its own "personal" paging area. Each time the wireless terminal emerges from a sleep state, it listens for the base station having the best signal and compares its identification against the list of base stations in its personal paging area. If the best signal base station is on the list, any paging messages for the wireless terminal are automatically broadcast by that base station. Otherwise, the wireless terminal must conduct a handoff to that base station to obtain a new personal paging area centered on that base station with that base station as paging agent. Messages originating elsewhere in the network are forwarded to the paging agent for delivery to the wireless terminal. The paging agent then instructs all known base stations within prescribed number of handoffs of it to page the wireless terminal. The wireless terminal, on hearing the page, will form a connection with the base station having the best signal for communicating. The base station having the best signal for communicating notifies the paging agent that it has established a connection with the wireless terminal, which leaves paging mode and becomes active.
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公开(公告)号：CA2330780C
公开(公告)日：2004-07-06
申请号：CA2330780
申请日：2001-01-10
Applicant: LUCENT TECHNOLOGIES INC
Inventor： DAVIES STEPHEN WILLIAM , VANDERVEEN MICHAELA C
Abstract: The penalties associated with relying on layer-4 to handle packets lost as a result of a handoff can be reduced by forwarding, in response to a handoff request from a first base station to a second base station, at least one layer-2 fra me of a layer-3 packet destined to/from the wireless terminal that has been passed down from layer-3 to layer-2, and so is indicated to have been transmitted at lay er- 3 even though not all of the layer-2 frames of the layer-3 packet have actually bee n transmitted. In one embodiment of the invention, each of the at least one layer-2 frames may be encapsulated together in a special layer-3 packet that is transferred from the first base to the second base station in the usual manner of inter- base- station communication. Advantageously, packets are not lost at layer-4 due t o handoffs. Thus, layer-4 retransmissions are not required, and so delays in t he network are reduced. Furthermore, if only the layer-2 frames that were not transmitted over the air to the wireless terminal by the first base station are transferred to the second base station, a savings may be had in use of the a ir interface.
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公开(公告)号：AU1676201A
公开(公告)日：2001-08-16
申请号：AU1676201
申请日：2001-02-01
Applicant: LUCENT TECHNOLOGIES INC
Inventor： DAVIES STEPHEN WILLIAM , VANDERVEEN MICHAELA C
Abstract: At least portions of the map of the base stations, i.e., which base stations are neighbors, is discovered and updated using a wireless terminal controlled handoff process. The portion of the map that is discovered by a particular base station is typically its neighbors to which -it can possibly hand off a call it is serving. It takes at least one handoff with each such base station neighbor for the particular base station to discover its entire local map, i.e., all the base stations to which the particular base station can perform handoffs. The wireless terminal handoff process is used to supply a base station with information about other base stations with whom the base station can cooperate to perform handoffs. The handoff process may subsequently be performed more expeditiously between the particular base station and such other base stations using the obtained information. As part of the handoff process, the wireless terminal tells the new base station to which it is handing off the call the identity of the previous base station from which control is being handed off. The wireless terminal then completes handoff and begins to be served by the new base station. If the new base station does not have a valid record for the previous base station, it forms a trust relationship with the previous base station and creates a record for it, thus identifying it as a neighbor to which it can perform expedited handoff in response to the control of a wireless terminal.
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