US6175587B1 — Communication device and method for interference …

Claim 1

Independent Claim 73 words

A method for receiving signals in a receiver having a plurality of receiver circuits, the method comprising the steps of: at each receiver circuit, detecting received multipath elements; at each receiver circuit, ranking the detected received multipath elements according to predetermined criteria; at each receiver circuit, selecting one or more interference vectors for suppression according to the ranking; and combining soft handoff multipath elements of the ranked multipath elements to form received signals.

Claim 2

Independent Claim 73 words

A method for receiving signals in a receiver having a plurality of receiver circuits, the method comprising the steps of: at each receiver circuit, detecting received multipath elements; at each receiver circuit, ranking the detected received multipath elements according to predetermined criteria; at each receiver circuit, selecting one or more interference vectors for suppression according to the ranking; and combining soft handoff multipath elements of the ranked multipath elements to form received signals.

Claim 3

Dependent Claim 54 words

A method as recited in claim 1 wherein the step of detecting the multipath elements comprises identifying a Walsh code assigned to the receiver by a base station of a communications system, the Walsh code corresponding to the multipath elements, and wherein ranking the received multipath elements comprises ranking multipath and Walsh code pairs.

Claim 4

Dependent Claim 48 words

A method as recited in claim 2 wherein the receiver is in soft handoff with one or more of the received multipath elements, and wherein combining the soft handoff multipath elements comprises combining multipath elements of the detected multipath elements corresponding to the soft handoff with the receiver.

Claim 5

Dependent Claim 31 words

A method as recited in claim 1 further comprising the step of, at each receiver circuit, completely suppressing multipath elements of the detected received multipath elements which meet a predetermined criterion.

Claim 6

Dependent Claim 126 words

A method as recited in claim 1 , further comprising the steps of: assigning each receiver of the plurality of receiver circuits to an assigned multipath element from the detected received multipath elements for demodulation by the receiver; ranking interference from a sector corresponding to the assigned multipath element according to a predetermined criterion; ranking interference from one or more multipath elements, of the detected received multipath elements, from sectors in soft handoff with the receiver according to the predetermined criterion; ranking interference from one or more multipath elements, of the detected received multipath elements, from sectors not in soft handoff with the receiver according to the predetermined criterion; and selecting one or more multipath and Walsh code pairs for suppression according to the interference rankings.

Claim 7

Dependent Claim 67 words

A method as recited in claim 5 further comprising the steps of: identifying interfering traffic channels among the one or more multipath elements; determining interference vectors corresponding to the interfering traffic channels; in response to the interference vectors, forming an orthogonal projection of a desired code; and correlating the one or more multipath elements with an appropriate orthogonal projection to completely suppress the identified interfering traffic channels.

Claim 8

Dependent Claim 21 words

A method as recited in claim 6 wherein identifying traffic channels comprises performing a Fast Hadamard Transform on a multipath element.

Claim 9

Independent Claim 95 words

A method for receiving signals in a DS-CDMA communication system, the method comprising the steps of: providing a RAKE receiver having a plurality of receiver fingers; identifying a first multipath element; assigning a first receiver finger to the first multipath element; demodulating the first multipath element; identifying a second multipath element; assigning a second receiver finger to the second multipath element; suppressing interference from a base station corresponding to delay of the second multipath element and identified by the second receiver finger; and otherwise, demodulating the second multipath element for combination with other multipath elements.

Claim 10

Independent Claim 95 words

A method for receiving signals in a DS-CDMA communication system, the method comprising the steps of: providing a RAKE receiver having a plurality of receiver fingers; identifying a first multipath element; assigning a first receiver finger to the first multipath element; demodulating the first multipath element; identifying a second multipath element; assigning a second receiver finger to the second multipath element; suppressing interference from a base station corresponding to delay of the second multipath element and identified by the second receiver finger; and otherwise, demodulating the second multipath element for combination with other multipath elements.

Claim 11

Dependent Claim 33 words

A method as recited in claim 8 wherein the step of demodulating comprises combining the second multipath element only if it corresponds to the base station in soft handoff with the RAKE receiver.

Claim 12

Independent Claim 70 words

A method for receiving radio signals at a receiver, the method comprising the steps of: (a) receiving a plurality of signals; (b) determining a signal quality parameter for each of the plurality of signals; (c) ranking the plurality of signals according to the signal quality parameter and selecting signals according to a predetermined criteria; (d) suppressing the selected signals according to rank; and (e) combining remaining signals as received data.

Claim 13

Independent Claim 70 words

A method for receiving radio signals at a receiver, the method comprising the steps of: (a) receiving a plurality of signals; (b) determining a signal quality parameter for each of the plurality of signals; (c) ranking the plurality of signals according to the signal quality parameter and selecting signals according to a predetermined criteria; (d) suppressing the selected signals according to rank; and (e) combining remaining signals as received data.

Claim 14

Dependent Claim 23 words

A method as recited in claim 10 wherein combining the remaining signals comprises combining only signals received in soft handoff with the receiver.

Claim 15

Dependent Claim 68 words

A method as recited in claim 10 wherein step (a) comprises the steps of: (a1) providing a RAKE receiver having a plurality of receiver fingers; and (a2) assigning the receiver fingers to one or more multipath elements, including a first multipath element, a second multipath element and a third multipath element, only the first multipath element and the second multipath element having sufficient signal quality to initiate communication.

Claim 16

Dependent Claim 34 words

A method as recited in claim 12 wherein multipath and Walsh code pairs interfering with a receiver finger are ranked according to the signal quality parameter independently of rankings performed at other receiver fingers.

Claim 17

Dependent Claim 26 words

A method as recited in claim 13 further comprising the step of performing a Fast Hadamard Transform at each receiver finger to identify traffic channels present.

Claim 18

Dependent Claim 66 words

A method as recited in claim 14 wherein performing the Fast Hadamard Transform comprises producing a list of Walsh codes for the traffic channels present and wherein suppressing selected signals comprises: (d1) forming a projection of a Walsh code corresponding to a desired traffic channel orthogonal to the signals to be suppressed; and (d2) correlating each of the traffic channels present using an appropriate orthogonal projection.

Claim 19

Dependent Claim 26 words

A method as recited in claim 12 wherein steps (b)-(d) are performed on the plurality of receiver fingers on a receiver finger by receiver finger basis.

Claim 20

Dependent Claim 93 words

A communication system comprising: a base station which transmits radio frequency (RF) signals, the RF signals formed by mixing a baseband signal with an RF carrier, the baseband signal being formed by spreading symbols with a periodic spreading sequence having a period substantially greater than a number of chips per symbol; and a mobile station including a receiver which receives the RF signals, producing downconverted RF signals, an interference ranking circuit for identifying interference, and an interference suppression correlator which completely suppresses the interference while demodulating the downconverted RF signals, producing received data.

Claim 21

Dependent Claim 93 words

A communication system comprising: a base station which transmits radio frequency (RF) signals, the RF signals formed by mixing a baseband signal with an RF carrier, the baseband signal being formed by spreading symbols with a periodic spreading sequence having a period substantially greater than a number of chips per symbol; and a mobile station including a receiver which receives the RF signals, producing downconverted RF signals, an interference ranking circuit for identifying interference, and an interference suppression correlator which completely suppresses the interference while demodulating the downconverted RF signals, producing received data.

Claim 22

Dependent Claim 33 words

A communication system as recited in claim 17 wherein the receiver of the mobile station is a RAKE receiver including a plurality of receiver fingers, each receiver finger including an interference suppression correlator.

Claim 23

Dependent Claim 24 words

A communication system as recited in claim 18 wherein each receiver finger further includes a despreader for despreading received data using the spreading sequence.

Claim 24

Dependent Claim 35 words

A communication system as recited in claim 17 wherein the interference ranking circuit comprises means for estimating and ranking interference according to predetermined criteria and means for selecting interference to be suppressed according to rank.

Claim 25

Dependent Claim 28 words

A communication system as recited in claim 20 wherein the mobile station further comprises a plurality of receiver circuits, each receiver circuit including independent means for ranking interference.

Claim 26

Dependent Claim 35 words

A communication system as recited in claim 21 wherein the interference ranking circuit further comprises a Fast Hadamard Transform calculator for determining which traffic channels are present and estimating relative strength of the traffic channels.

Claim 27

Dependent Claim 35 words

A communication system as recited in claim 20 wherein the mobile station further comprises means for producing one or more interference vectors, the one or more interference vectors corresponding to the interference to be suppressed.

Claim 28

Dependent Claim 35 words

A communication system as recited in claim 23 wherein the mobile station further comprises an orthogonal projection calculator which calculates an orthogonal projection of a desired code relative to the one or more interference vectors.

Claim 29

Dependent Claim 16 words

A communication system as recited in claim 24 wherein the desired code is a Walsh code.

Claim 30

Dependent Claim 21 words

A communication system as recited in claim 24 wherein the interference suppression correlator correlates the orthogonal projection and the received data.

Claim 31

Dependent Claim 46 words

A communication system as recited in claim 17 wherein the mobile station receives a desired code from the base station, the mobile station further comprising an orthogonal projection calculator which calculates an orthogonal projection of the desired code, the orthogonal projection being orthogonal to the interference.

Claim 32

Independent Claim 56 words

A method for receiving data from a remote transmitter in a communication system, the method comprising the steps of: receiving at a receiver a desired code; detecting interference at the receiver; calculating an orthogonal projection of the desired code in response to the interference; and demodulating received data from the remote transmitter using the orthogonal projection.

Claim 33

Independent Claim 56 words

A method for receiving data from a remote transmitter in a communication system, the method comprising the steps of: receiving at a receiver a desired code; detecting interference at the receiver; calculating an orthogonal projection of the desired code in response to the interference; and demodulating received data from the remote transmitter using the orthogonal projection.

Claim 34

Dependent Claim 25 words

A method as recited in claim 28 further comprising the steps of forming interference vectors and ranking the interference vectors according to a predetermined criterion.

Claim 35

Dependent Claim 17 words

A method as recited in claim 28 wherein the step of demodulating data comprises suppressing the interference.

Claim 36

Dependent Claim 18 words

A method as recited in claim 28 wherein demodulating data comprises correlating the data and the orthogonal projection.

Claim 37

Dependent Claim 44 words

A method as recited in claim 28 further comprising the step of providing a RAKE receiver having a plurality of receiver fingers, and wherein calculating the orthogonal projection and demodulating data are done independently at each receiver finger of the plurality of receiver fingers.

Claim 38

Independent Claim 112 words

A method for receiving radio symbols at a communication device, the method comprising the steps of: (a) receiving a plurality of signals corresponding to a set of multipath delay elements; (b) determining a signal quality parameter for each of the set of multipath delay elements; (c) selecting a subset of the set of multipath delay elements in soft handoff with the communication device for combining according to the signal quality parameter; (d) for each of the subset of multipath delay elements, being combined, selecting a set of interfering signals to be suppressed; and (e) combining the selected subset of multipath delay elements after suppressing the set of interfering signals to be suppressed.

Claim 39

Independent Claim 112 words

A method for receiving radio symbols at a communication device, the method comprising the steps of: (a) receiving a plurality of signals corresponding to a set of multipath delay elements; (b) determining a signal quality parameter for each of the set of multipath delay elements; (c) selecting a subset of the set of multipath delay elements in soft handoff with the communication device for combining according to the signal quality parameter; (d) for each of the subset of multipath delay elements, being combined, selecting a set of interfering signals to be suppressed; and (e) combining the selected subset of multipath delay elements after suppressing the set of interfering signals to be suppressed.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2004-01-16	2004-07-17	2005-01-16	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2008-01-16	2008-07-17	2009-01-16	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2012-01-16	2012-07-17	2013-01-16	$7700.00	Window Closed / Lapsed

Communication device and method for interference suppression in a DS-CDMA system

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