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公开(公告)号：DE60100534T2
公开(公告)日：2004-05-27
申请号：DE60100534
申请日：2001-08-20
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LAROIA RAJIV , LI JUNYI , UPPALA SATHYADEV VENKATA
Abstract: Latency in receiving and detecting paging messages at a wireless terminal is reduced by employing a unique "super" paging time slot format. A paging super time slot includes a plurality of prescribed time slots. Each wireless terminal is associated with cyclically recurring super time slots. A super slot is associated with one or more wireless terminals. A base station always selects the first available time slot in a super time slot to transmit a paging message to a wireless terminal that is associated with the super time slot. Each wireless terminal monitors every time slot in the associated super time slot until either detecting reception of its associated paging message or detecting an empty time slot. In another embodiment of the invention, a unique partially overlapping super time slot format is employed in which a super time slot has at least one time slot common to its adjacent super time slots. This allows wireless terminals associated with adjacent super time slots to share the common at least one time slot. In turn, this results in balanced traffic loads, smoothed traffic fluctuation and reduced congestion.
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公开(公告)号：CA2359514A1
公开(公告)日：2002-05-03
申请号：CA2359514
申请日：2001-10-22
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LAROIA RAJIV , UPPALA SATHYADEV VENKATA , LI JUNYI
Abstract: In a wireless communications system, multicast messages are transported to groups of wireless terminals by employing a common control channel to transm it a multicast paging message indicating that multicast traffic data is to be transmitted to a particular group of wireless terminals. In an embodiment of the invention, t he essential information transmitted in the common control channel is the identifier of t he group of wireless terminals intended to receive the multicast traffic data and the location of a traffic channel on which the multicast traffic is to be transported in a channel resource which may include a representation of bandwidth and time interval. In accordance with an aspect of the invention, the common control channel is associated with a traffic channel in a prescribed fixed manner. Further, the traffic channel used for the purpose of multicast can be the same traffic channel used for the normal point-to- point transmission of traffic data.
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公开(公告)号：DE60000096D1
公开(公告)日：2002-05-02
申请号：DE60000096
申请日：2000-02-28
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LAROIA RAJIV , LI JUNYI , VANDERVEEN MICHAELA CATALINA
Abstract: In an orthogonal frequency division multiplexing (OFDM) based spread spectrum 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 ratio at the mobile transmitter, each voice user is allocated preferably a single one, but no more than a very small number, of the orthogonal tones for use in communicating with the 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 within 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 tone to another. However, in the uplink, preferably slow hopping is employed to allow efficient modulation of the uplink signal which necessitates the employing of additional 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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公开(公告)号：AU5191201A
公开(公告)日：2001-12-20
申请号：AU5191201
申请日：2001-06-14
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LAROIA RAJIV , LI JUNYI , UPPALA SATHYADEV VENKATA
IPC: H04W24/00 , H04W28/04 , H04W68/00 , H04W72/04 , H04W74/00 , H04Q7/22 , H04Q7/30 , H04Q7/32 , H04Q7/26
Abstract: In a wireless communication system, mobile unit and base station access request and page transmissions are addressed by employing an efficient unified approach for the transmission and detection of both access requests from a mobile unit and pages from a base station. To this end, a mobile unit monitors for access requests and monitors a prescribed resource to detect if a page has been received. Upon detection of an access request, a corresponding request message is generated and transmitting substantially immediately to a base station, thereby minimizing latency in the access process. Concurrently, a base station monitors to determine if a page indication has been received and monitors a prescribed resource to determine if an access request message has been received. In this process, the processing of request messages takes precedence over the processing of pages. Upon detecting a received request message a request response message is generated and transmitted substantially immediately to the mobile unit, thereby also minimizing latency in the access process.
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公开(公告)号：BR0101426A
公开(公告)日：2001-11-13
申请号：BR0101426
申请日：2001-04-09
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LAROIA RAJIV , RANGAN DEEP , LI JUNYI , VISWANATH PRAMOD
IPC: H04B1/713 , H04B1/7143 , H04B1/7156 , H04B7/26 , H04J11/00 , H04L5/02 , H04L27/26 , H04Q7/22
Abstract: A base station having the strongest downlink signal is identified by utilizing a unique slope of a pilot tone hopping sequence being transmitted by a base station. Specifically, base station identification is realized by determining the slope of the strongest received pilot signal, i.e., the received pilot signal having the maximum energy. In an embodiment of the invention, the pilot tone hopping sequence is based on a Latin Squares sequence. With a Latin Squares based pilot tone hopping sequence, all a mobile user unit needs is to locate the frequency of the pilot tones at one time because the pilot tone locations at subsequent times can be determined from the slope of the Latin Squares pilot tone hopping sequence. The slope and initial frequency shift of the pilot tone hopping sequence with the strongest received power is determined by employing a unique maximum energy detector. In one embodiment, the slope and initial frequency shift of the pilot signal having the strongest received power is determined by finding the slope and initial frequency shift of a predicted set of pilot tone locations having the maximum received energy. In another embodiment, the frequency shift of the pilot signal with the strongest, i.e., maximum, received power is estimated at each of times "t". These frequency shifts are employed in accordance with a prescribed relationship to determine the unknown slope and the initial frequency shift of the pilot signal.
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Patent Agency Ranking
公开(公告)号：CA2330776A1
公开(公告)日：2001-08-11
申请号：CA2330776
申请日：2001-01-12
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LI JUNYI , LAROIA RAJIV , RANGAN SUNDEEP , UPPALA SATHYADEV VENKATA
Abstract: Signal construction, detection and estimation techniques for use in uplink timing synchronization and access control in an orthogonal frequency division multiplexed (OFDM) wireless system or other type of wireless communication system. In accordanc e with an illustrative embodiment of the invention, timing and access signals to be transmitted in designated timing and access intervals are constructed from orthogonal multitone signals. The multitone signals may be similar to multitone signals used in OFDM data transmission, except that a cyclic prefix associated with reception of the signals in a ba se station is extended to cover the timing errors of mobile stations not yet synchronized. The invention also provides design techniques which optimize the time resolvability and pe ak- to-average ratio of the multitone signals, an efficient fast Fourier transform (FFT) based technique for maximum likelihood timing estimation, and a robust linear filtering techniqu e for averaging timing estimates from different synchronizations.
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公开(公告)号：AU7229800A
公开(公告)日：2001-06-28
申请号：AU7229800
申请日：2000-12-15
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LAROIA RAJIV , LI JUNYI , RANGAN SUNDEEP , UPPALA SATHYADEV VENKATA
IPC: H04J11/00 , H04B1/7136 , H04B1/7143 , H04L5/02 , H04J13/02
Abstract: Tone sequences in a frequency hopping arrangement are generated and assigned by advantageously employing a combination of a sequence generator and a sequence assignor to generate sequences and assign them on a time slot by time slot basis. In a transmitter, the sequence generator and sequence assignor, in combination with a user tone assignor are employed to generate and assign tone sequences to a user on a time slot by time slot basis. In a receiver, the sequence generator and sequence assignor, in combination with a user tone identifier are employed to generate sequences and to identify incoming tone sequences to a user on a time slot by time slot basis. Specifically, the sequence assignment in a time slot is such that a prescribed plurality of sequences is assigned to a particular user. This partitioning of the tasks facilitates the use of a sequence generator that generates sequences with the desirable properties of interference and frequency diversity and, which, leaves the task of properly assigning these sequences among one or more users to the sequence assignor. The sequence assignor functions in such a manner that the interference and frequency diversity properties for the one or more users are preserved, and this is further facilitated by assigning sequences in such a manner that they maximally overlap prior assigned sequences. In one example of the invention, a Latin square based sequence is generated in accordance with a first prescribed process. In an embodiment of the invention, a Latin cube based sequence is generated in accordance with a second prescribed process. In another embodiment of the invention, a Latin hypercube of prescribed dimension based sequence is generated in accordance with a third prescribed process. In still another embodiment of the invention, the principles of the invention are employed to realize frequency band hopping.
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公开(公告)号：AU1956700A
公开(公告)日：2000-09-14
申请号：AU1956700
申请日：2000-03-01
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LAROIA RAJIV , LI JUNYI , VANDERVEEN MICHAELA C
Abstract: In an orthogonal frequency division multiplexing (OFDM) based spread spectrum 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 ratio at the mobile transmitter, each voice user is allocated preferably a single one, but no more than a very small number, of the orthogonal tones for use in communicating with the 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 within 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 tone to another. However, in the uplink, preferably slow hopping is employed to allow efficient modulation of the uplink signal which necessitates the employing of additional 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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公开(公告)号：CA2299568A1
公开(公告)日：2000-09-11
申请号：CA2299568
申请日：2000-02-24
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LI JUNYI , VANDERVEEN MICHAELA C , LAROIA RAJIV
Abstract: A base station within a cell of an orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access system employs sectorization as a way to reduce the intercell interference. The cell is sectorized from a transmission point of view by the directionality of the downlink antenna, and the OFDM tone set employed in each cell is correspondingly sectorized, i.e., each sector in the cell is allocated a set of tones within a sub-band of the available frequency bandwidth for use when transmitting into that sector. The sub-bands assigned to each sector are periodically changed, or "hopped", among the available sub-bands within the totally available bandwidth. Such subband hopping is a so-called "slow" hopping, in that it is not performed on a symbolby-symbol basis but instead occurs only after more than one symbol has been transmitted in a sector on tones within the sub-band. Each sector employs its own pilot signal, which is assigned one or more tones within the sub-band currently employed by that sector. Similarly, for the uplink, the base station may employ a directional receiver antenna. Preferably, the mobile terminal only transmits on a tone that is within a sub-band that is allocated to the sector in which the mobile terminal is located. This, sub-band, however, need not correspond to the same location within the bandwidth as the sub-band used by the downlink to communicate with the mobile terminal.
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公开(公告)号：CA2271508A1
公开(公告)日：1999-12-19
申请号：CA2271508
申请日：1999-05-11
Applicant: LUCENT TECHNOLOGIES INC
Inventor： LAROIA RAJIV , WANG JIN-DER
Abstract: In an Asymmetric Digital Subscriber Loop (ADSL) Discrete Multi-Tone (DMT) system, ADSL DMT equipment includes an encoder that operates on a DMT input signal representing f symbols/sec. to generate, for transmission, a DMT output signal representing Nf symbols/sec., where N > l, and where each symbol from the DMT input signal is generated in a redundant form in the DMT output signal. In one example of a redundant form, each symbol from the DMT input signal is repeated in N consecutive symbol intervals in the DMT output signal. In another example of a redundant form, every N DMT input symbol values are transmitted in 2N consecutive symbol intervals in the DMT output signal. These 2N consecutive symbols in the DMT output signal include 1) N symbols whose values equal the respective N DMT input symbol values and 2) N symbols whose values are a function of the respective N DMT input symbol values.
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