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US 8,284,793 B2Granted
Backoff control for access probe transmission in communication systems
AssigneeQUALCOMM Incorporated
InventorArvind Vardarajan Santhanam
Life of this patent
Estimating the term…
Abstract
A random backoff time can be determined and the transmission of an initial access probe can be delayed for the random backoff time. A backoff interval can be determined based on channel load, wherein the backoff interval defines a range from which the random backoff time is selected.
Claims24
A method comprising:
- determining a backoff interval based an estimate of a number of access terminals (N) attempting to access an access channel;
- determining a random backoff time, wherein the backoff interval defines a range from which the random backoff time is selected;
- randomly selecting the random backoff time from the backoff interval of [0, D−1]*Tac, wherein D is an integer and Tac is approximately one access cycle;
- and
- delaying transmission of an initial access probe for the random backoff time, wherein D is a non-decreasing function of N, and wherein D is equal to N for N less than a predetermined value and wherein D is equal to the predetermined value for N greater than or equal to the predetermined value.
2 more elements
A method comprising:
- determining a backoff interval based an estimate of a number of access terminals (N) attempting to access an access channel;
- determining a random backoff time, wherein the backoff interval defines a range from which the random backoff time is selected;
- randomly selecting the random backoff time from the backoff interval of [0, D−1]*Tac, wherein D is an integer and Tac is approximately one access cycle;
- and
- delaying transmission of an initial access probe for the random backoff time, wherein D is a non-decreasing function of N, and wherein D is set to a value greater than or equal to N for low values of N and wherein D is set to a value of less than or equal to N for large values of N.
2 more elements
A method comprising:
- determining a backoff interval based an estimate of a number of access terminals (N) attempting to access an access channel;
- establishing a quality of service constraint, wherein the quality of service constraint is further used in determining the backoff interval;
- determining a random backoff time, wherein the backoff interval defines a range from which the random backoff time is selected;
- establishing a delay constraint as a maximum delay (Lmax) for a given percentile (Q) of the successful transmission of K access probes out of a total of N simultaneous access probes on the access channel, wherein the quality of service constraint is based on the delay constraint, and
- delaying transmission of an initial access probe for the random backoff time.
2 more elements
A method comprising:
- determining a backoff interval based an estimate of a number of access terminals (N) attempting to access an access channel;
- establishing a quality of service constraint, wherein the quality of service constraint is further used in determining the backoff interval;
- determining a random backoff time, wherein the backoff interval defines a range from which the random backoff time is selected;
- and
- delaying transmission of an initial access probe for the random backoff time, wherein the quality of service constraint is defined as:
- 1
- -
- ∑
- M
- =
- N
- -
- R
- +
- 1
- N
-
- ∑
- K
- =
- 1
- ⌊
- M
- 2
- ⌋
-
- P
- K
- M
-
- (
- N
- ,
- D
- )
- ≥
- P
- 0
- .
- where P0 is a probability of success, R is a number of successful access probes, and K denotes a number of access cycle durations in which a collision event takes place when N access probes contend to transmit over the access channel and where PKM(N, D) denotes a probability of M probes colliding in K collision events when N access probes begin access procedures at the same time and delay probe transmission by a random amount of time (in an interval [0, D−1] Access Cycle durations) prior to a first access attempt.
37 more elements
A method comprising:
- determining a backoff interval based an estimate of a number of access terminals (N) attempting to access an access channel;
- determining a random backoff time, wherein the backoff interval defines a range from which the random backoff time is selected;
- randomly selecting the random backoff time from the backoff interval of [0, D−1]*Tac, wherein D is an integer and Tac is approximately one access cycle;
- and
- delaying transmission of an initial access probe for the random backoff time, wherein the backoff interval is adjusted to compensate for a capture effect in a wireless network, wherein the capture effect acts as a weighting function to allow the backoff interval to be adjusted based on a likelihood that a probe will be successfully received even in an event of a collision and wherein the capture effect is determined as:
- P
- K
- M
-
- (
- N
- ,
- D
- )
- =
- ∑
- i
- 1
- ,
- i
- 2
- ,
- …
-
- ,
- i
- K
-
- {
- 1
- K
- !
-
- N
- !
- i
- 1
- !
-
- i
- 2
- !
-
-
- …
-
-
- i
- K
- !
-
- (
- N
- -
- M
- )
- !
-
- D
- !
- (
- D
- -
- K
- -
- (
- N
- -
- M
- )
- )
- !
-
- ∏
- k
- =
- 1
- K
-
-
- (
- 1
- -
- A
- i
- k
- )
- }
- .
- where Aik is a probability of decoding one access probe when ik probes are transmitted simultaneously using the same PN code, and where PKM(N, D) denotes the probability of M probes colliding in K collision events when N access probes begin access procedures at the same time and defer their probe transmission by a random amount of time (in an interval [0, D−1] Access Cycle durations) prior to the first access attempt.
87 more elements
An apparatus comprising:
- logic configured to determine a random backoff time;
- logic configured to determine a backoff interval based on an estimate of a number of access terminals (N) attempting to access an access channel, wherein the backoff interval defines a range from which the random backoff time is selected;
- logic configured to randomly select the random backoff time from the backoff interval of [0, D−1]*Tac, wherein D is an integer and Tac is approximately one access cycle;
- and
- logic configured to delay transmission of an initial access probe for the random backoff time, wherein D is set to a value greater than or equal to N for low values of N and wherein D is set to a value of less than or equal to N for large values of N.
2 more elements
An apparatus comprising:
- logic configured to determine a random backoff time;I
- logic configured to determine a backoff interval based on an estimate of a number of access terminals (N) attempting to access an access channel, wherein the backoff interval defines a range from which the random backoff time is selected;
- logic configured to randomly select the random backoff time from the backoff interval of [0, D−1]*Tac, wherein D is an integer and Tac is approximately one access cycle;
- and
- logic configured to delay transmission of an initial access probe for the random backoff time, wherein D is set to a predetermined value for a range of N.
2 more elements
An apparatus comprising:
- logic configured to determine a random backoff time;
- logic configured to determine a backoff interval based on an estimate of a number of access terminals (N) attempting to access an access channel, wherein the backoff interval defines a range from which the random backoff time is selected;
- logic configured to establish a quality of service constraint, wherein the quality of service constraint is further used in determining the backoff interval;
- logic configured to establish a delay constraint as a maximum delay (Lmax) for a given percentile (Q) of the successful transmission of K access probes out of a total of N simultaneous access probes on the access channel, wherein the quality of service constraint is based on the delay constraint;
- and
- logic configured to delay transmission of an initial access probe for the random backoff time.
3 more elements
An apparatus comprising:
- logic configured to determine a random backoff time;
- logic configured to determine a backoff interval based on an estimate of a number of access terminals (N) attempting to access an access channel, wherein the backoff interval defines a range from which the random backoff time is selected;
- logic configured to establish a quality of service constraint, wherein the quality of service constraint is further used in determining the backoff interval;
- and
- logic configured to delay transmission of an initial access probe for the random backoff time, wherein the quality of service constraint is defined as:
- 1
- -
- ∑
- M
- =
- N
- -
- R
- +
- 1
- N
-
- ∑
- K
- =
- 1
- ⌊
- M
- 2
- ⌋
-
- P
- K
- M
-
- (
- N
- ,
- D
- )
- ≥
- P
- 0
- .
- where P0 is a probability of success, R is a number of successful access probes, and K denotes a number of access cycle durations in which a collision event takes place when N access probes contend to transmit over the access channel.
37 more elements
An access terminal comprising:
- means for determining a backoff interval based on an estimate of a number of access terminals (N) attempting to access an access channel;
- means for determining a random backoff time, wherein the backoff interval defines a range from which the random backoff time is selected;
- means for randomly selecting the random backoff time from the backoff interval of [0, D−1]*Tac, wherein D is an integer and Tac is approximately one access cycle;
- and
- means for delaying transmission of an initial access probe for the random backoff time, wherein D is set to a value greater than or equal to N for low values of N and wherein D is set to a value of less than or equal to N for large values of N.
2 more elements
A non-transitory computer readable medium embodying a method for execution by a processor in a wireless communication system, the method comprising:
- determining a backoff interval based on channel load of an access channel;
- determining a random backoff time, wherein the backoff interval defines a range from which the random backoff time is selected;
- randomly selecting the random backoff time from the backoff interval of [0, D−1]*Tac, wherein D is an integer and Tac is approximately one access cycle;
- and
- delaying transmission of an initial access probe for the random backoff time, wherein D is set to a value greater than or equal to N for low values of N and wherein D is set to a value of less than or equal to N for large values of N.
2 more elements
Dependencies are inferred from the claim text.