US5886988A — Channel assignment and call admission control for…

Claim 1

Independent Claim 175 words

A channel assignment method for use in a wireless communication system for establishing an uplink connection between a subscriber station requesting an uplink connection and a base station, and for reassigning an existing connection to a subscriber station, the base station including an array of antenna elements and SDMA processing means, the SDMA processing means enabling one or more subscriber stations to communicate on the uplink with the base station on the same conventional channel, each subscriber station communicating on the same conventional channel communicating on a spatial channel of said same conventional channel, the method comprising: (a) for each conventional uplink channel, computing a cost according to a cost function that is indicative of the interference level that may be realized by assigning the subscriber station to the conventional uplink channel, the cost function being a function of spatial properties of the subscriber station for communicating with the base station; and (b) assigning to the subscriber station one of the conventional uplink channels with a cost that is less than a prescribed cost threshold.

Claim 2

Dependent Claim 175 words

A channel assignment method for use in a wireless communication system for establishing an uplink connection between a subscriber station requesting an uplink connection and a base station, and for reassigning an existing connection to a subscriber station, the base station including an array of antenna elements and SDMA processing means, the SDMA processing means enabling one or more subscriber stations to communicate on the uplink with the base station on the same conventional channel, each subscriber station communicating on the same conventional channel communicating on a spatial channel of said same conventional channel, the method comprising: (a) for each conventional uplink channel, computing a cost according to a cost function that is indicative of the interference level that may be realized by assigning the subscriber station to the conventional uplink channel, the cost function being a function of spatial properties of the subscriber station for communicating with the base station; and (b) assigning to the subscriber station one of the conventional uplink channels with a cost that is less than a prescribed cost threshold.

Claim 3

Dependent Claim 78 words

The method of claim 1 wherein the SDMA processing means enables more than one subscriber station to communicate on the uplink with the base station on the same conventional channel, the method further comprising the step of assigning a new spatial channel to the subscriber station on the assigned conventional channel if the assigned conventional channel is in use by the base station for communicating on the unlink with a second subscriber station on an existing spatial channel.

Claim 4

Dependent Claim 14 words

The method of claim 1 wherein the assigned conventional channel has a minimal cost.

Claim 5

Dependent Claim 65 words

The method of claim 1 wherein the SDMA processing means processes uplink signals from a particular subscriber station according to a set of uplink demultiplexing weights for that particular subscriber station, wherein the spatial properties are the elements of the uplink spatial signature of the subscriber station, and wherein the cost function is a quadratic function of the uplink spatial signature of the subscriber station.

Claim 6

Dependent Claim 23 words

The method of claim 4 wherein the cost function is a weighted quadratic function of the uplink spatial signature of the subscriber station.

Claim 7

Dependent Claim 29 words

The method of claim 5 wherein the cost function is weighted by a sample covariance matrix of the base station antenna array received vector signal for a conventional channel.

Claim 8

Dependent Claim 97 words

The method of claim 1 wherein the SDMA processing means processes a uplink signals from a particular subscriber station according to a set of uplink demultiplexing weights for that particular subscriber station, wherein the spatial properties are the elements of the uplink spatial signature of the subscriber station, and wherein the cost function, c k , is computed as c.sub.k =a.sub.k.sup.* R.sub.zz.sup.(k) a.sub.k where a k is the conventional channel k uplink spatial signature of the subscriber station, and R zz .sup.(k) is a sample covariance matrix of the base station antenna array response on channel k.

Claim 9

Dependent Claim 46 words

The method of claim 7 wherein the sample covariance matrix, R zz .sup.(k), is estimated as an average from the received signal vectors, z.sup.(k) (i), at the base station antenna array on conventional channel k, where i is a received signal vector sample index, as ##EQU11##

Claim 10

Dependent Claim 89 words

The method of claim 7 wherein the sample covariance matrix, R zz .sup.(k),is estimated as R.sub.zz.sup.(k) =A.sub.k R.sub.ss.sup.(k) A.sub.k.sup.* +R.sub.nn where A k is a collection of spatial signatures formed by column-wise concatenation of all spatial signatures of subscriber stations actively communicating with the base station on conventional channel k, R ss .sup.(k) is a covariance matrix whose diagonal elements are average transmit powers of subscribers communicating with the base station, and R nn .sup.(k ) is a noise-plus-interference covariance matrix of the base station antenna array received signals.

Claim 11

Dependent Claim 94 words

The method of claim 9 wherein R nn .sup.(k ) is estimated as R.sub.nn.sup.(k) =A.sub.k.sup.0 R.sub.s.sbsb.0.sub.s.sbsb.0.sup.(k) A.sub.k.sup.0* +σ.sup.2 I where A k 0 is a collection of spatial signatures of subscriber stations not communicating with the base station and is formed by column-wise concatenation of the spatial signatures on conventional channel k, and R s .sbsb.0 s .sbsb.0.sup.(k) is a covariance matrix whose diagonal elements are the average transmit signal powers of subscriber stations not communicating with the base station, σ 2 is an estimated receiver noise power, and I is an identity matrix.

Claim 12

Dependent Claim 45 words

The method of claim 1 wherein the cost function is based on at least one uplink received signal quality factor selected from the group consisting of a received uplink signal level, a signal-to-interference-plus-noise ratio, an interference-plus-noise level, an intermodulation noise level, and a crest factor.

Claim 13

Dependent Claim 199 words

A channel assignment method for use in a wireless communication system for establishing an uplink connection between a subscriber station requesting an uplink connection and a base station, and for reassigning an existing connection to a subscriber station, the base station including an array of antenna elements and SDMA processing means, the SDMA processing means enabling one or more subscriber stations to communicate on the uplink with the base station on the same conventional channel, each subscriber station communicating on the same conventional channel communicating on a spatial channel of said same conventional channel, the method comprising: (a) for each conventional uplink channel, computing a predicted cost according to a cost function, the cost function for a particular conventional channel based on the predicted received signal quality on the particular conventional channel, the received signal quality on a conventional uplink channel predicted using a model of the wireless communication system for predicting signal quality based upon existing connections, the computing using spatial properties of the subscriber station for communicating with the base station; and (b) assigning to the subscriber station one of the conventional uplink channels that has a predicted cost that is less than a prescribed cost level.

Claim 14

Dependent Claim 199 words

A channel assignment method for use in a wireless communication system for establishing an uplink connection between a subscriber station requesting an uplink connection and a base station, and for reassigning an existing connection to a subscriber station, the base station including an array of antenna elements and SDMA processing means, the SDMA processing means enabling one or more subscriber stations to communicate on the uplink with the base station on the same conventional channel, each subscriber station communicating on the same conventional channel communicating on a spatial channel of said same conventional channel, the method comprising: (a) for each conventional uplink channel, computing a predicted cost according to a cost function, the cost function for a particular conventional channel based on the predicted received signal quality on the particular conventional channel, the received signal quality on a conventional uplink channel predicted using a model of the wireless communication system for predicting signal quality based upon existing connections, the computing using spatial properties of the subscriber station for communicating with the base station; and (b) assigning to the subscriber station one of the conventional uplink channels that has a predicted cost that is less than a prescribed cost level.

Claim 15

Dependent Claim 78 words

The method of claim 12 wherein the SDMA processing means enables more than one subscriber stations to communicate on the uplink with the base station on the same conventional channel, the method further comprising the step of assigning a new spatial channel to the subscriber station on the assigned conventional channel if the assigned conventional channel is in use by the base station for communicating on the uplink with a second subscriber station on an existing spatial channel.

Claim 16

Dependent Claim 19 words

The method of claim 12 wherein the predicted received signal quality is based on predicting an uplink interference-plus-noise level.

Claim 17

Dependent Claim 22 words

The method of claim 12 wherein the predicted received signal quality is based on predicting a received signal to interference-plus-noise ration (SINR).

Claim 18

Dependent Claim 19 words

The method of claim 12 wherein the prescribed cost level corresponds to a minimal acceptable received bit error rate.

Claim 19

Dependent Claim 17 words

The method of claim 12 wherein the assigned conventional uplink channel has a predicted minimal cost level.

Claim 20

Dependent Claim 28 words

The method of claim 12 wherein assigning step (b) further requires that the assigned conventional channel have a SINR level that is greater than a prescribed minimal value.

Claim 21

Dependent Claim 160 words

The method of claim 12 wherein the spatial properties are the elements of the uplink spatial signature of the subscriber station, and wherein step (a) for computing further comprises: (i) updating a covariance matrix of received uplink signals, R zz .sup.(k), representative of received uplink signals at the base station before assigning channel k by predicting an updated covariance matrix, R zz .sup.(k), representative of received uplink signals that would result if the new subscriber were to be assigned to channel k, where R zz .sup.(k) =R zz .sup.(k) +a k , r ss .sup.(k) +a k , a k * ,a k is the uplink spatial signature of the new subscriber on conventional channel k, and r ss .sup.(k) is a scalar representative of the new subscriber transmitted power on conventional channel k; and (ii) computing an uplink spatial demultiplexing weight vector, w k U , where w k U =(R zz .sup.(k)) -1 a k r ss .sup.(k).

Claim 22

Dependent Claim 31 words

The method of claim 19 wherein the updated inverse covariance matrix, (R zz .sup.(k)) -1 , is obtained from the expression (R.sub.zz.sup.(k)).sup.-1 =(R.sub.zz.sup.(k)).sup.-1 -(R.sub.zz.sup.(k)).sup.-1 a.sub.k .sub.k.sup.* (R.sub.zz.sup.(k)).sup.-1 /((1/r.sub.ss.sup.(k))+a.sub.k.sup.* (R.sub.zz.sup.(k)).sub.-1 a.sub.k). 21.

Claim 23

Dependent Claim 167 words

The method of claim 12 wherein the spatial properties are the elements of the uplink spatial signature of the subscriber station, and wherein step (a) for computing the predicted uplink received signal quality level on channel k further comprises: (iii) predicting uplink received signal power as S k U =|w k U* a k | 2 r ss .sup.(k) ; (iv) predicting uplink interference-plus-noise power for the new subscriber as I k U =w k U* R zz .sup.(k) w k U ; and (v) predicting the uplink SINR for channel k as SINR k =S k U /I k U where R zz .sup.(k) is the sample covariance matrix of the base station antenna array response on conventional channel k, a k is the uplink spatial signature of the new subscriber on conventional channel k, r ss .sup.(k) is a scalar representative of the new subscriber transmitted power on conventional channel k, and w k U is the uplink spatial demultiplexing weight vector for channel k.

Claim 24

Dependent Claim 40 words

The method of claim 12 further comprising a constraint for only permitting assignment of a conventional channel if the assignment results in a predicted uplink SINR for all active subscribers using the conventional channel which exceeds a prescribed SINR level.

Claim 25

Dependent Claim 42 words

The method of claim 12 wherein the predicted cost is based on at least one set of predicted uplink received signal quality factors selected from the group consisting of received uplink signal levels, interference-plus-noise levels, intermodulation noise levels, and crest factor values.

Claim 26

Dependent Claim 236 words

A channel assignment method for use in a wireless communication system for establishing an uplink connection between a new subscriber station requesting an uplink connection and a base station, and for reassigning an existing connection to a subscriber station the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) computing a first cost for each conventional uplink channel according to a first cost function that is indicative of the uplink interference level that may be realized by assigning the new subscriber station to said each conventional uplink channel, the computing including using spatial properties of the subscriber station for communicating with the base station; (b) selecting a subset of conventional uplink channels, the subset consisting of the conventional uplink channels with a first cost that is less than a prescribed first cost level; (c) for each conventional uplink channel of the subset, computing a second cost according to a second cost function, the second cost function for a particular conventional channel based on the predicted received signal quality on the particular conventional channel, the received signal quality on a conventional uplink channel predicted using a model of the wireless communication system for predicting signal quality based upon existing connections; and (d) assigning to the subscriber station one of the conventional uplink channels of the subset that has a second cost that is less than a prescribed second cost level.

Claim 27

Dependent Claim 236 words

A channel assignment method for use in a wireless communication system for establishing an uplink connection between a new subscriber station requesting an uplink connection and a base station, and for reassigning an existing connection to a subscriber station the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) computing a first cost for each conventional uplink channel according to a first cost function that is indicative of the uplink interference level that may be realized by assigning the new subscriber station to said each conventional uplink channel, the computing including using spatial properties of the subscriber station for communicating with the base station; (b) selecting a subset of conventional uplink channels, the subset consisting of the conventional uplink channels with a first cost that is less than a prescribed first cost level; (c) for each conventional uplink channel of the subset, computing a second cost according to a second cost function, the second cost function for a particular conventional channel based on the predicted received signal quality on the particular conventional channel, the received signal quality on a conventional uplink channel predicted using a model of the wireless communication system for predicting signal quality based upon existing connections; and (d) assigning to the subscriber station one of the conventional uplink channels of the subset that has a second cost that is less than a prescribed second cost level.

Claim 28

Dependent Claim 100 words

The method of claim 24 wherein the SDMA processing means enables more than one subscriber stations to communicate on the uplink with the base station on the same conventional channel, each subscriber station communicating on the same conventional channel communicating on a different spatial channel of said same conventional channel, the method further comprising the step of assigning a new spatial channel to the subscriber station on the assigned conventional uplink channel if the assigned conventional uplink channel is in use by the base station for communicating on the uplink with a second subscriber station on an existing spatial channel.

Claim 29

Dependent Claim 24 words

The method of claim 24 wherein the prescribed first and second cost levels correspond to a prescribed maximal received uplink bit error rate level.

Claim 30

Dependent Claim 29 words

The method of claim 24 wherein step (d) of assigning further requires that the assigned conventional channel have a SINR level that is higher than a prescribed SINR level.

Claim 31

Dependent Claim 42 words

The method of claim 24, wherein the wireless communication system uses power control when establishing an uplink connection, and wherein in step d), a conventional uplink channel is selected for assignment that has a SINR level greater than a prescribed SINR level.

Claim 32

Dependent Claim 38 words

The method of claim 24 wherein is based on at least one set of uplink received signal quality factors selected from the following list: received uplink signal power levels, interference-plus-noise levels, intermodulation noise levels, and crest factor values.

Claim 33

Dependent Claim 218 words

A channel assignment method for use in a wireless communication system for establishing a downlink connection between a base station and a subscriber station, the base station including an array of antenna elements and SDMA processing means, the SDMA processing means enabling the base station to communicate on the downlink with more than one subscriber station on the same conventional channel, each subscriber station on the same conventional channel being communicated to on a different spatial channel of said same conventional channel, the method comprising: (a) estimating, at the base station, the downlink received interference-plus-noise level that would result for each existing conventional channel if the subscriber was assigned to a given conventional downlink channel; (b) computing, at the base station, a cost for each existing conventional downlink channel using a prescribed cost function based on the estimated downlink received interference-plus-noise levels; and (c) assigning, at the base station, the subscriber station to a conventional downlink channel that has a computed cost that is less than a prescribed value, the method further comprising the step of assigning a spatial channel to the subscriber station on the assigned conventional downlink channel if the assigned conventional downlink channel is in use by the base station for communicating on the downlink with a second subscriber station on an existing spatial channel.

Claim 34

Dependent Claim 218 words

A channel assignment method for use in a wireless communication system for establishing a downlink connection between a base station and a subscriber station, the base station including an array of antenna elements and SDMA processing means, the SDMA processing means enabling the base station to communicate on the downlink with more than one subscriber station on the same conventional channel, each subscriber station on the same conventional channel being communicated to on a different spatial channel of said same conventional channel, the method comprising: (a) estimating, at the base station, the downlink received interference-plus-noise level that would result for each existing conventional channel if the subscriber was assigned to a given conventional downlink channel; (b) computing, at the base station, a cost for each existing conventional downlink channel using a prescribed cost function based on the estimated downlink received interference-plus-noise levels; and (c) assigning, at the base station, the subscriber station to a conventional downlink channel that has a computed cost that is less than a prescribed value, the method further comprising the step of assigning a spatial channel to the subscriber station on the assigned conventional downlink channel if the assigned conventional downlink channel is in use by the base station for communicating on the downlink with a second subscriber station on an existing spatial channel.

Claim 35

Dependent Claim 21 words

The method of claim 30 wherein assigning step (c) further comprises selecting a downlink channel that has a minimal computed cost.

Claim 36

Dependent Claim 57 words

The method of claim 30 wherein estimating step (a) further comprises: (i) measuring, at the subscriber station, downlink received signal levels on each downlink channel and reporting the downlink received signal levels to the base station; (ii) estimating, at the base station, the downlink received interference-plus-noise levels from the reported downlink signal levels of measuring step (i).

Claim 37

Dependent Claim 47 words

The method of claim 32 wherein measuring step (i) of estimating step (a) further comprises each subscriber station, when not actively engaged in a call, periodically measuring the downlink received signal level on each conventional channel and reporting the downlink received signal levels to the base station.

Claim 38

Dependent Claim 21 words

The method of claim 32 wherein the downlink received interference-plus-noise levels are estimated as being the reported downlink received signal levels.

Claim 39

Dependent Claim 262 words

A channel assignment method for use in a wireless communication system for establishing a downlink connection between a base station and a subscriber station, the base station including an array of antenna elements and SDMA processing means, the SDMA processing means processing a downlink signal for a particular subscriber station according to a set of downlink multiplexing weights for that particular subscriber station, the method comprising: (a) estimating, at the base station, the downlink received interference-plus-noise level that would result for each existing conventional channel if the subscriber was assigned to a given conventional downlink channel; (b) computing, at the base station, a cost for each existing conventional downlink channel using a prescribed cost function based on the estimated downlink received interference-plus-noise levels; and (c) assigning, at the base station, a conventional downlink channel that has a computed cost that is less than a prescribed value, wherein step (a) for estimating downlink received interference-plus-noise levels on each downlink channel comprises the following steps: (i) adjusting, at the base station, each existing subscriber's downlink multiplexing weights as if the new subscriber was assigned to a given conventional channel; (ii) measuring, at the new subscriber station, the downlink received signal level on the given channel after step (i) and reporting the downlink received signal level to the base station; (iii) predicting, at the base station, a downlink interference-plus-noise level from the downlink received signal level of step (ii); and (iv) readjusting, at the base station, each existing subscriber's downlink multiplexing weights as if the new subscriber was not assigned to the given conventional channel.

Claim 40

Dependent Claim 262 words

A channel assignment method for use in a wireless communication system for establishing a downlink connection between a base station and a subscriber station, the base station including an array of antenna elements and SDMA processing means, the SDMA processing means processing a downlink signal for a particular subscriber station according to a set of downlink multiplexing weights for that particular subscriber station, the method comprising: (a) estimating, at the base station, the downlink received interference-plus-noise level that would result for each existing conventional channel if the subscriber was assigned to a given conventional downlink channel; (b) computing, at the base station, a cost for each existing conventional downlink channel using a prescribed cost function based on the estimated downlink received interference-plus-noise levels; and (c) assigning, at the base station, a conventional downlink channel that has a computed cost that is less than a prescribed value, wherein step (a) for estimating downlink received interference-plus-noise levels on each downlink channel comprises the following steps: (i) adjusting, at the base station, each existing subscriber's downlink multiplexing weights as if the new subscriber was assigned to a given conventional channel; (ii) measuring, at the new subscriber station, the downlink received signal level on the given channel after step (i) and reporting the downlink received signal level to the base station; (iii) predicting, at the base station, a downlink interference-plus-noise level from the downlink received signal level of step (ii); and (iv) readjusting, at the base station, each existing subscriber's downlink multiplexing weights as if the new subscriber was not assigned to the given conventional channel.

Claim 41

Dependent Claim 218 words

A channel assignment method for use in a wireless communication system for establishing a downlink connection between a base station and a subscriber station, the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) estimating, at the base station, the downlink received interference-plus-noise level that would result for each existing conventional channel if the subscriber was assigned to a given conventional downlink channel; (b) computing, at the base station, a cost for each existing conventional downlink channel using a prescribed cost function based on the estimated downlink received interference-plus-noise levels; and (d) assigning, at the base station, a conventional downlink channel that has a computed cost that is less than a prescribed value, wherein step (a) for estimating a downlink received interference-plus-noise level, I k , for each existing channel k comprises, modeling the downlink received interference-plus-noise level, I k , as a sum of the noise contribution, N k , and a predicted second interference signal level that would result if the new subscriber was to be assigned to channel k, estimating the noise contribution N k as a signal level difference between a measured downlink received signal level, P k , on channel k and a computed first interference signal level due to all base stations using channel k.

Claim 42

Dependent Claim 218 words

A channel assignment method for use in a wireless communication system for establishing a downlink connection between a base station and a subscriber station, the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) estimating, at the base station, the downlink received interference-plus-noise level that would result for each existing conventional channel if the subscriber was assigned to a given conventional downlink channel; (b) computing, at the base station, a cost for each existing conventional downlink channel using a prescribed cost function based on the estimated downlink received interference-plus-noise levels; and (d) assigning, at the base station, a conventional downlink channel that has a computed cost that is less than a prescribed value, wherein step (a) for estimating a downlink received interference-plus-noise level, I k , for each existing channel k comprises, modeling the downlink received interference-plus-noise level, I k , as a sum of the noise contribution, N k , and a predicted second interference signal level that would result if the new subscriber was to be assigned to channel k, estimating the noise contribution N k as a signal level difference between a measured downlink received signal level, P k , on channel k and a computed first interference signal level due to all base stations using channel k.

Claim 43

Dependent Claim 136 words

The method of claim 36 wherein the SDMA Processing means processes a downlink signal for a particular subscriber station according to a set of downlink multiplexing weights for that particular subscriber station, wherein each subscriber station has a downlink spatial signature, and wherein the computed first interference signal level is computed as ##EQU12## where W k ,j D* =S k ,j A k ,j.sup.†, S k ,j is a diagonal matrix of base station j transmitted signal amplitudes, A k ,j is a column-wise concatenated matrix of known downlink spatial signatures at base station j for the subscriber stations on conventional channel k, A k ,j.sup.† represents the pseudoinverse of A k ,j, and a k D ,j is the downlink spatial signature for the new subscriber station on conventional channel k from base station j.

Claim 44

Dependent Claim 143 words

The method of claim 36 wherein the SDMA processing means processes a downlink signal for a particular subscriber station according to a set of downlink multiplexing weights for that particular subscriber station, wherein each subscriber station has a downlink spatial signature, and wherein the predicted second interference signal level for channel k is computed as ##EQU13## where ##EQU14## † represents a pseudoinverse operation, S k ,j is a diagonal matrix of transmit signal amplitudes, A k ,j is a column-wise concatenated matrix of known downlink spatial signatures for the subscriber stations on conventional channel k at base station j, a k D ,j is a downlink spatial signature for conventional channel k from base station j for the new subscriber station on conventional channel k, and w * is the bottom row of matrix Sk,j A k ,j a k D ,j !.sup.†.

Claim 45

Dependent Claim 190 words

A channel assignment method for use in a wireless communication system for establishing a downlink connection between a base station and a subscriber station, the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) estimating, at the base station, the downlink received interference-plus-noise level that would result for each existing conventional channel if the subscriber was assigned to a given conventional downlink channel; (b) computing, at the base station, a cost for each existing conventional downlink channel using a prescribed cost function based on the estimated downlink received interference-plus-noise levels; and (c) assigning, at the base station, a conventional downlink channel that has a computed cost that is less than a prescribed value, and further comprising a step for assigning a selected downlink conventional channel) only if it is expected to result in an acceptable downlink received signal quality for each active subscriber using the selected conventional channel based upon at least one downlink quality factor selected from a group consisting of: predicted cost; predicted total base station transmitter power; predicted intermodulation distortion level; predicted interference-plus-noise level; and predicted signal to interference-plus-noise ratio.

Claim 46

Dependent Claim 190 words

A channel assignment method for use in a wireless communication system for establishing a downlink connection between a base station and a subscriber station, the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) estimating, at the base station, the downlink received interference-plus-noise level that would result for each existing conventional channel if the subscriber was assigned to a given conventional downlink channel; (b) computing, at the base station, a cost for each existing conventional downlink channel using a prescribed cost function based on the estimated downlink received interference-plus-noise levels; and (c) assigning, at the base station, a conventional downlink channel that has a computed cost that is less than a prescribed value, and further comprising a step for assigning a selected downlink conventional channel) only if it is expected to result in an acceptable downlink received signal quality for each active subscriber using the selected conventional channel based upon at least one downlink quality factor selected from a group consisting of: predicted cost; predicted total base station transmitter power; predicted intermodulation distortion level; predicted interference-plus-noise level; and predicted signal to interference-plus-noise ratio.

Claim 47

Dependent Claim 48 words

The method of claim 39 wherein the predicted intermodulation distortion level is obtained by computing a crest factor for each downlink !conventional downlink channel, the crest factor value being indicative of an intermodulation distortion level that would result if a given conventional downlink channel were to be assigned.

Claim 48

Dependent Claim 205 words

A channel assignment method for use in a wireless communication system for establishing a downlink connection between a base station and a subscriber station, the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) estimating, at the base station, the downlink received SINR level that would result for each existing conventional channel if the subscriber station were to be assigned to a given conventional downlink channel, the estimating using spatial information of the new subscriber; (b) computing, at the base station, a cost for each existing conventional downlink channel using a prescribed cost function based on the estimated downlink received SNR level; and (c) assigning, at the base station, a downlink channel that has a computed cost that is less than a prescribed value, the method further comprising the step of assigning a spatial channel to the subscriber station on the assigned conventional downlink channel if the communications system supports and the SDMA processing means enables communication on more than one spatial channel on the same conventional downlink channel, and if the assigned conventional downlink channel is in use by the base station for communicating on the downlink with a second subscriber station on an existing spatial channel.

Claim 49

Dependent Claim 205 words

A channel assignment method for use in a wireless communication system for establishing a downlink connection between a base station and a subscriber station, the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) estimating, at the base station, the downlink received SINR level that would result for each existing conventional channel if the subscriber station were to be assigned to a given conventional downlink channel, the estimating using spatial information of the new subscriber; (b) computing, at the base station, a cost for each existing conventional downlink channel using a prescribed cost function based on the estimated downlink received SNR level; and (c) assigning, at the base station, a downlink channel that has a computed cost that is less than a prescribed value, the method further comprising the step of assigning a spatial channel to the subscriber station on the assigned conventional downlink channel if the communications system supports and the SDMA processing means enables communication on more than one spatial channel on the same conventional downlink channel, and if the assigned conventional downlink channel is in use by the base station for communicating on the downlink with a second subscriber station on an existing spatial channel.

Claim 50

Dependent Claim 102 words

The method of claim 41 wherein the SDMA processing means enables more than one subscriber stations to communicate on the downlink with the base station on the same conventional downlink channel, each subscriber station on the same conventional channel being communicated to on a different spatial channel of said same conventional channel, the method further comprising the step of assigning a new spatial channel to the subscriber station on the assigned conventional downlink channel if the assigned conventional downlink channel is in use by the base station for communicating on the downlink with a second subscriber station on an existing spatial channel.

Claim 51

Dependent Claim 132 words

The method of claim 41 wherein the SDMA processing means processes a downlink signal for a particular subscriber station according to a set of downlink multiplexing weights for that particular subscriber station, wherein each subscriber station has a downlink spatial signature, and wherein the prescribed cost function of computing step (b) is based on SINR k D , an estimated downlink signal to interference-plus-noise ratio for each channel k, where SINR k D =S k D /I k D , S k D =|w k D* a k D | 2 , w k D is the downlink multiplexing weight for the new subscriber on channel k, a k D is the downlink spatial signature of the new subscriber on channel k, and I k D is an estimated k interference-plus-noise level.

Claim 52

Dependent Claim 21 words

The method of claim 41 wherein assigning step (c) further comprises selecting a downlink channel that has a minimal computed cost.

Claim 53

Dependent Claim 57 words

The method of claim 41 wherein estimating step (a) further comprises: (i) measuring, at the subscriber station, downlink received signal levels on each downlink channel and reporting the downlink received signal levels to the base station; (ii) estimating, at the base station, the downlink received interference-plus-noise level from the reported downlink signal levels of measuring step (i).

Claim 54

Dependent Claim 47 words

The method of claim 45 wherein measuring step (i) of estimating step (a) further comprises each subscriber station, when not actively engaged in a call, periodically measuring the downlink received signal level on each conventional channel and reporting the downlink received signal levels to the base station.

Claim 55

Dependent Claim 150 words

The method of claim 41 wherein the SDMA processing means processes a downlink signal for a particular subscriber station according to a set of downlink multiplexing weights for that particular subscriber station, and wherein step (a) for estimating downlink received interference-plus-noise levels on each downlink channel comprises the following steps: (i) adjusting, at the base station, each existing subscriber's downlink multiplexing weights as if the new subscriber was assigned to a given conventional channel; (ii) measuring, at the new subscriber station, the downlink received signal level on the given channel after adjusting step (i) and reporting the downlink received signal level to the base station; (iii) predicting, at the base station, a downlink interference-plus-noise level from the downlink received signal level of measuring step (ii); and (iv)readjusting, at the base station, each existing subscriber's downlink multiplexing weights as if the new subscriber were not assigned to the given conventional channel.

Claim 56

Dependent Claim 103 words

The method of claim 41 wherein step (a) for estimating a downlink received interference-plus-noise level, I k , for each existing channel k comprises, modeling the downlink received interference-plus-noise level, I k , as a sum of the noise contribution, N k , and a predicted second interference signal level that would result if the new subscriber was to be assigned to channel k, estimating the noise contribution N k as a signal level difference between a measured downlink received signal level, P k , on channel k and a computed first interference signal level due to all base stations using channel k.

Claim 57

Dependent Claim 143 words

The method of claim 48 wherein the SDMA Processing means processes a downlink signal for a particular subscriber station according to a set of downlink multiplexing weights for that particular subscriber station, wherein each subscriber station has a downlink spatial signature, and wherein the computed first interference signal level is computed as ##EQU15## where W k ,j D* =S k ,j D* =S k ,j A k ,j.sup.†, S k ,j is a diagonal matrix of base station j transmitted signal amplitudes for conventional channel k, A k ,j is a column-wise concatenated matrix of known spatial signatures at base station j for the subscriber stations on conventional channel k, A k ,j.sup.† represents the pseudoinverse of A k ,j, and a k D ,j is a downlink spatial signature for the new subscriber station on conventional channel k from base station j.

Claim 58

Dependent Claim 141 words

The method of claim 48 wherein the SDMA processing means processes a downlink signal for a particular subscriber station according to a set of downlink multiplexing weights for that particular subscriber station, wherein each subscriber station has a downlink spatial signature, and wherein the predicted second interference signal level for channel k is computed as ##EQU16## where ##EQU17## † represents a pseudoinverse operation, S k ,j is a diagonal matrix of transmit signal amplitudes, A k ,j is a column-wise concatenated matrix of known downlink spatial signatures at base station j for the subscriber stations on conventional channel k, a k D ,j is a downlink spatial signature for the new subscriber station on conventional channel k from base station j, and w * is the bottom row of matrix S k ,j A k ,j a k D ,j !.sup.†.

Claim 59

Dependent Claim 78 words

The method of claim 41 further comprising a step for assigning a selected conventional downlink channel only if it is expected to result in an acceptable downlink received signal quality for each active channel based upon at least one downlink quality factor selected from a group consisting of: cost for new call; total base station transmitter power; predicted intermodulation distortion level; predicted interference-plus-noise level on each active channel; and predicted signal to interference-plus-noise ratio on each active channel.

Claim 60

Dependent Claim 47 words

The method of claim 51 wherein the predicted intermodulation distortion level is obtained by computing a crest factor for each conventional downlink channel, the crest factor value being indicative of an intermodulation distortion level that would result if a given conventional downlink channel were to be assigned.

Claim 61

Dependent Claim 176 words

In a wireless communication system, the system including a base station and one or more subscriber stations, the base station including an array of antenna elements and SDMA processing means, a method for assignment of a full-duplex channel in which a duplex channel is selected from a set of duplex channels wherein each duplex channel of the set provides acceptable quality uplink communications, and the downlink channel assignment is made in accordance with existing rules of the system, the method comprising: (a) computing a cost for each conventional uplink channel according to a cost function that is indicative of a lack of communications quality expected interference level that may be realized by assigning the subscriber station to the conventional uplink channel, the cost function being a function of spatial properties of the subscriber station for communicating with the base station; (b) assigning a conventional uplink channel by selecting a conventional uplink channel with a cost less than a prescribed cost level; and (c) selecting a downlink channel in accordance with existing rules of the communication system.

Claim 62

Dependent Claim 176 words

In a wireless communication system, the system including a base station and one or more subscriber stations, the base station including an array of antenna elements and SDMA processing means, a method for assignment of a full-duplex channel in which a duplex channel is selected from a set of duplex channels wherein each duplex channel of the set provides acceptable quality uplink communications, and the downlink channel assignment is made in accordance with existing rules of the system, the method comprising: (a) computing a cost for each conventional uplink channel according to a cost function that is indicative of a lack of communications quality expected interference level that may be realized by assigning the subscriber station to the conventional uplink channel, the cost function being a function of spatial properties of the subscriber station for communicating with the base station; (b) assigning a conventional uplink channel by selecting a conventional uplink channel with a cost less than a prescribed cost level; and (c) selecting a downlink channel in accordance with existing rules of the communication system.

Claim 63

Dependent Claim 22 words

The method of claim 53 wherein the full duplex channel assignment is made in accordance with the Personal Handyphone System (PHS) standard.

Claim 64

Dependent Claim 204 words

In a wireless communication system, the system including a base station and one or more subscriber stations, the base station including an array of antenna elements and SDMA processing means, the SDMA processing means enabling the base station to communicate on the downlink with more than one subscriber station on the same conventional channel, each subscriber station on the same conventional channel being communicated to by the base station on a different spatial channel of said same conventional channel, a method for assignment of a full-duplex channel in which a duplex channel is selected from a set of duplex channels wherein each duplex channel of the set provides acceptable quality downlink communications, and the uplink channel assignment is made in accordance with existing rules of the system, the method comprising: (a) computing a cost for each conventional downlink channel according to a cost function that estimates a lack of communications quality expected from existing connections on each conventional downlink channel, if a given conventional downlink channel was assigned; (b) assigning a conventional downlink channel by selecting a conventional downlink channel with a cost less than a prescribed cost level; and (c) selecting a uplink channel in accordance with existing rules of the communication system.

Claim 65

Dependent Claim 204 words

In a wireless communication system, the system including a base station and one or more subscriber stations, the base station including an array of antenna elements and SDMA processing means, the SDMA processing means enabling the base station to communicate on the downlink with more than one subscriber station on the same conventional channel, each subscriber station on the same conventional channel being communicated to by the base station on a different spatial channel of said same conventional channel, a method for assignment of a full-duplex channel in which a duplex channel is selected from a set of duplex channels wherein each duplex channel of the set provides acceptable quality downlink communications, and the uplink channel assignment is made in accordance with existing rules of the system, the method comprising: (a) computing a cost for each conventional downlink channel according to a cost function that estimates a lack of communications quality expected from existing connections on each conventional downlink channel, if a given conventional downlink channel was assigned; (b) assigning a conventional downlink channel by selecting a conventional downlink channel with a cost less than a prescribed cost level; and (c) selecting a uplink channel in accordance with existing rules of the communication system.

Claim 66

Dependent Claim 132 words

In a wireless communication system, the system including a base station and one or more subscriber stations, the base station including an array of antenna elements and SDMA processing means, a method for assignment of a full-duplex channel in which a duplex channel is selected from a set of duplex channels wherein each duplex channel of the set provides acceptable quality downlink and uplink communications, the method comprising: (a) computing a cost for each conventional duplex channel according to a cost function that is indicative of a lack of communications quality expected from existing connections on each conventional duplex channel, the cost function including spatial properties of the subscriber station; and (b) assigning a conventional duplex channel by selecting a conventional duplex channel with a cost less than a prescribed cost level.

Claim 67

Dependent Claim 132 words

In a wireless communication system, the system including a base station and one or more subscriber stations, the base station including an array of antenna elements and SDMA processing means, a method for assignment of a full-duplex channel in which a duplex channel is selected from a set of duplex channels wherein each duplex channel of the set provides acceptable quality downlink and uplink communications, the method comprising: (a) computing a cost for each conventional duplex channel according to a cost function that is indicative of a lack of communications quality expected from existing connections on each conventional duplex channel, the cost function including spatial properties of the subscriber station; and (b) assigning a conventional duplex channel by selecting a conventional duplex channel with a cost less than a prescribed cost level.

Claim 68

Dependent Claim 134 words

A call admission control method, based on an interference cost function, for use in a wireless communication system for controlling admission of a connection for a new subscriber station, the system including a base station and one or more subscriber stations, the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) evaluating a cost for a selected conventional channel according to a cost function that is indicative of the interference-plus-noise on the selected conventional channel if the selected conventional channel were to be assigned, the evaluation using spatial properties of the subscriber station for communicating with the base station; (b) comparing the cost with a prescribed channel assignment cost level; and (c) admitting the call if the cost is less than the prescribed channel assignment cost level.

Claim 69

Dependent Claim 134 words

A call admission control method, based on an interference cost function, for use in a wireless communication system for controlling admission of a connection for a new subscriber station, the system including a base station and one or more subscriber stations, the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) evaluating a cost for a selected conventional channel according to a cost function that is indicative of the interference-plus-noise on the selected conventional channel if the selected conventional channel were to be assigned, the evaluation using spatial properties of the subscriber station for communicating with the base station; (b) comparing the cost with a prescribed channel assignment cost level; and (c) admitting the call if the cost is less than the prescribed channel assignment cost level.

Claim 70

Dependent Claim 212 words

A call admission control method for use in a wireless communication system for controlling admission of a connection for a new subscriber station, the system including a base station and one or more subscriber stations, the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) predicting the received signal level and interference-plus-noise level on each conventional channel based upon a model of the wireless communication system for predicting a received signal level and interference-plus-noise level on each conventional channel based upon existing connections, if a given conventional channel was assigned for the new subscriber station; (b) selecting a conventional channel for the new subscriber station that has an acceptably high predicted signal-to-interference-plus-noise ratio (SINR) determined according to predicting step (a); and (c) admitting the call if the SINR is greater than a prescribed admission level SINR threshold value, the method further comprising the step of assigning a spatial channel for the call on the selected conventional channel if the communications system supports and the SDMA processing means enables communication on more than one spatial channel on the same conventional channel, and if the assigned conventional channel is in use by the base station for communicating with a second subscriber station on an existing spatial channel.

Claim 71

Dependent Claim 212 words

A call admission control method for use in a wireless communication system for controlling admission of a connection for a new subscriber station, the system including a base station and one or more subscriber stations, the base station including an array of antenna elements and SDMA processing means, the method comprising: (a) predicting the received signal level and interference-plus-noise level on each conventional channel based upon a model of the wireless communication system for predicting a received signal level and interference-plus-noise level on each conventional channel based upon existing connections, if a given conventional channel was assigned for the new subscriber station; (b) selecting a conventional channel for the new subscriber station that has an acceptably high predicted signal-to-interference-plus-noise ratio (SINR) determined according to predicting step (a); and (c) admitting the call if the SINR is greater than a prescribed admission level SINR threshold value, the method further comprising the step of assigning a spatial channel for the call on the selected conventional channel if the communications system supports and the SDMA processing means enables communication on more than one spatial channel on the same conventional channel, and if the assigned conventional channel is in use by the base station for communicating with a second subscriber station on an existing spatial channel.

Claim 72

Dependent Claim 129 words

A call admission control method for use in a wireless communication system for controlling admission of a connection of a new subscriber station, the method, based on an estimate of existing system call load, comprising: (a) estimating the existing call load for indicating how much of the system capacity is being utilized; (b) prescribing a call load threshold that is indicative of a maximal call load allowed for the system; and (c) comparing the existing call load with the call load threshold; and (d) admitting a new call if the estimated existing call load is less than the call load threshold, wherein estimating step (a) further comprises monitoring the rate at which intracell handoffs occur, and estimating the existing call load from the rate at which intracell handoffs occur.

Claim 73

Dependent Claim 129 words

A call admission control method for use in a wireless communication system for controlling admission of a connection of a new subscriber station, the method, based on an estimate of existing system call load, comprising: (a) estimating the existing call load for indicating how much of the system capacity is being utilized; (b) prescribing a call load threshold that is indicative of a maximal call load allowed for the system; and (c) comparing the existing call load with the call load threshold; and (d) admitting a new call if the estimated existing call load is less than the call load threshold, wherein estimating step (a) further comprises monitoring the rate at which intracell handoffs occur, and estimating the existing call load from the rate at which intracell handoffs occur.

Claim 74

Dependent Claim 119 words

A call admission control method for use in a wireless communication system for controlling admission of a connection of a new subscriber station, the method, based on an estimate of existing system call load, comprising: (a) estimating the existing call load for indicating how much of the system capacity is being utilized; (b) prescribing a call load threshold that is indicative of a maximal call load allowed for the system; and (c) comparing the existing call load with the call load threshold; and (e) admitting a new call if the estimated existing call load is less than the call load threshold, wherein estimating step (a) further comprises estimating the existing call load by monitoring the rate of channel reassignments.

Claim 75

Dependent Claim 119 words

A call admission control method for use in a wireless communication system for controlling admission of a connection of a new subscriber station, the method, based on an estimate of existing system call load, comprising: (a) estimating the existing call load for indicating how much of the system capacity is being utilized; (b) prescribing a call load threshold that is indicative of a maximal call load allowed for the system; and (c) comparing the existing call load with the call load threshold; and (e) admitting a new call if the estimated existing call load is less than the call load threshold, wherein estimating step (a) further comprises estimating the existing call load by monitoring the rate of channel reassignments.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2002-03-22	2002-09-21	2003-03-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2006-03-22	2006-09-21	2007-03-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2010-03-22	2010-09-21	2011-03-23	$7700.00	Window Closed / Lapsed

Channel assignment and call admission control for spatial division multiple access communication systems

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