U.S. patent application number 09/783154 was filed with the patent office on 2001-10-25 for method and apparatus for controlling mobile access to a wireless communication system.
This patent application is currently assigned to MOTOROLA, INC.. Invention is credited to Froula, Donald R..
Application Number | 20010034235 09/783154 |
Document ID | / |
Family ID | 26881455 |
Filed Date | 2001-10-25 |
United States Patent
Application |
20010034235 |
Kind Code |
A1 |
Froula, Donald R. |
October 25, 2001 |
Method and apparatus for controlling mobile access to a wireless
communication system
Abstract
The present invention provides a method and an apparatus for
controlling mobile access to a wireless communication system. A
base station (145) in a communication cell (165) monitors a
plurality of mobile access parameters. The base station (145)
generates control information based on the plurality of mobile
access parameters. The base station (145) provides mobile stations
(185, 190) within the communication cell (165) with the control
information to control access to the communication system by mobile
stations (185, 190) based on the mobile access overload class of
the mobile stations (185, 190) and the type of mobile access
attempted by the mobile stations (185, 190).
Inventors: |
Froula, Donald R.; (St.
Charles, IL) |
Correspondence
Address: |
MOTOROLA, INC.
1303 EAST ALGONQUIN ROAD
IL01/3RD
SCHAUMBURG
IL
60196
|
Assignee: |
MOTOROLA, INC.
|
Family ID: |
26881455 |
Appl. No.: |
09/783154 |
Filed: |
February 14, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60185770 |
Feb 29, 2000 |
|
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Current U.S.
Class: |
455/446 ;
455/434; 455/450; 455/453 |
Current CPC
Class: |
H04W 48/12 20130101;
H04W 74/006 20130101; H04W 4/90 20180201; H04W 76/50 20180201; H04W
74/0833 20130101 |
Class at
Publication: |
455/446 ;
455/435; 455/434; 455/450; 455/453 |
International
Class: |
H04Q 007/20 |
Claims
What is claimed:
1. In a wireless communication system providing communication
services for a communication cell having a plurality of sectors,
wherein each sector includes an access channel and a paging
channel, a method for controlling mobile access to the
communication system via the access channel, the method comprising
steps of: monitoring a plurality of mobile access parameters;
generating control information based on the plurality of mobile
access parameters; providing control information to a mobile
station through the paging channel; and wherein the mobile station
is adapted to access the communication system in accordance with
the control information and wherein the plurality of mobile access
parameters are associated with mobile access originated from the
plurality of sectors in the communication cell.
2. The method of claim 1, wherein the mobile access comprises at
least one or more of a data burst message, a registration, a page
acknowledgment, and a call origination.
3. The method of claim 1, wherein the step of monitoring a
plurality of mobile access parameters includes a step of monitoring
at least one or more of a first mobile access parameter, a second
mobile access parameter, and a third mobile access parameter.
4. The method of claim 3, wherein the first mobile access parameter
is associated with a mobile access originated within one of the
plurality of sectors in the communication cell.
5. The method of claim 3, wherein the second mobile access
parameter is associated with a registration originated within one
of the plurality of sectors in the communication cell.
6. The method of claim 3, wherein the third mobile access parameter
is associated with a data burst message originated within one of
the plurality of sectors in the communication cell.
7. The method of claim 1, wherein the step of monitoring a
plurality of mobile access parameters comprises a step of
monitoring an access rate of the plurality of mobile access.
8. The method of claim 1, wherein the step of generating control
information through the paging channel comprises a step of
generating control information comprising a plurality of
persistence access control parameters in an access parameter
message through the paging channel.
9. The method of claim 8, wherein the plurality of persistence
access control parameters comprises at least one or more of a base
persistence value and a persistence modifier.
10. The method of claim 9, wherein the base persistence value
identifies at least one or more of an overload class, a restriction
level for each of the plurality of mobile access, and an access
type.
11. The method of claim 9, wherein the persistence modifier
comprises at least one or more of a registration persistence value
and a message persistence value.
12. In a wireless communication system providing communication
services for a communication cell having a plurality of sectors,
wherein each sector includes an access channel and a paging
channel, an apparatus for controlling mobile access to the
communication system via the access channel, the apparatus
comprising: a mobile access detector adapted to monitor a plurality
of mobile access parameters; a memory adapted to contain operating
instructions; a processor coupled to the memory and the mobile
access detector, the processor operable on the base station in
accordance with the operating instructions to generate control
information; a transmitting unit coupled to processor; and wherein
the transmitting unit provides control information through the
paging channel and wherein the plurality of mobile access
parameters are associated with mobile access originated from the
plurality of sectors in the communication cell.
13. The apparatus of claim 12, wherein the mobile access comprises
at least one or more of a data burst message, a registration, a
page acknowledgment, and a call origination.
14. The apparatus of claim 12, wherein the plurality of mobile
access parameters comprises at least one or more of a first mobile
access parameter, a second mobile access parameter, and third
mobile access parameter.
15. The apparatus of claim 14, wherein the first mobile access
parameter is associated with a mobile access originated within one
of the plurality sectors in the communication cell.
16. The apparatus of claim 14, wherein the second mobile access
parameter is associated with a registration originated within one
of the plurality of sectors in the communication cell.
17. The apparatus of claim 14, wherein the third mobile access
parameter is associated with a data burst message originated within
one of the plurality of sectors in the communication cell.
18. The apparatus of claim 12, wherein the control information
comprises a plurality of persistence access control parameters.
19. The apparatus of claim 18, wherein the plurality of persistence
access control parameters comprises at least one or more of a base
persistence value and a persistence modifier.
20. The apparatus of claim 19, wherein the base persistence value
identifies at least one or more of an overload class and an access
type.
21. The apparatus of claim 19, wherein the persistence modifier
comprises at least one or more of a registration persistence value
and a message persistence value.
22. In a wireless communication system providing communication
services for a communication cell having a plurality of sectors,
wherein each sector includes an access channel and a paging
channel, and wherein a processor operates in accordance to a
computer program embodied on a computer-readable medium for
controlling mobile access to the communication system via the
access channel, the computer program comprising: a first routine
that directs the processor to monitor a plurality of mobile access
parameters; a second routine that directs the processor to generate
control information based on the plurality of mobile access
parameters; a third routine that directs the processor to provide
control information through the paging channel; and wherein the
plurality of mobile access parameters are associated with mobile
access originated within the plurality of sectors in the
communication cell.
23. The computer program of claim 22, wherein the medium comprises
one of paper, a programmable gate array, application specific
integrated circuit, erasable programmable read only memory, read
only memory, random access memory, magnetic media, and optical
media.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based on prior U.S. patent application
Ser. No. 60/185,770, filed Feb. 29, 2000, and priority thereto is
hereby claimed.
FIELD OF THE INVENTION
[0002] The present invention relates generally to wireless
communication systems, and more particularly, to a method and an
apparatus for controlling mobile access to a wireless communication
system.
Background of the Invention
[0003] A wireless communication system is a complex network of
systems and elements. Typical elements include (1) a radio link to
the mobile stations (e.g., cellular telephones), which is usually
provided by at least one and typically several base stations, (2)
communication links between the base stations, (3) a controller,
typically one or more base station controllers or centralized base
station controllers (BSC/CBSC), to control communication between
and to manage the operation and interaction of the base stations,
(4) a call controller or switch, typically a mobile switching
center (MSC), for routing calls within the system, and (5) a link
to the land line or public switch telephone network (PSTN), which
is usually also provided by the MSC.
[0004] In a wireless communication system, a mobile station
typically communicates to a base station over several communication
channels, e.g., a control channel, a traffic channel, and an access
channel. In particular, the mobile station uses the access channel
to signal to the base station, via a mobile access message, a
request to obtain communication services, i.e., to access the
communication system. The mobile access message may be, but is not
limited to, a registration, a data burst message, a page
acknowledgment, and a call origination initiated by the mobile
station that is transmitted via the access channel to the base
station. However, only unsolicited mobile access messages, i.e.,
originated without prompting by the base station, may be controlled
to access the communication system. Specifically, unsolicited
mobile access messages include registrations, data burst messages,
and call originations. A registration indicates the status of the
mobile station, i.e., whether the mobile station is active or
inactive, or the location of the mobile station, i.e., whether the
mobile station has moved into a different sector within a
communication cell. A data burst message includes a textual message
which may be destined for another mobile station, to a pager or a
MSC. A call origination is a request by the mobile station to
initiate a voice or data call.
[0005] One aspect of designing wireless communication systems is to
ensure a high level of access to the communication system by the
mobile stations. It is especially important that mobile stations
are able to access the communication system in critical situations
or where the mobile stations are identified as having high
priority. The communication system must also prevent such critical
and high priority mobile stations from being indiscriminately
denied access by base stations within the communication system when
the base stations experience overload conditions.
[0006] In critical situations, such as an earthquake or any other
type of natural disaster, a high volume of mobile access messages
originated by mobile stations is quite natural. Accordingly,
critical mobile access messages should have higher priority to
access the communication system than other non-critical
registrations, data burst messages, or call originations. For
example, a voice call originated from a mobile station used by a
fire fighter to request for more assistance should have higher
priority than other non-critical mobile access messages. Other
critical mobile access messages include access messages originated
from mobile stations used for special purposes such as, but not
limited to, system maintenance. However, current wireless
communication systems indiscriminately deny mobile access to the
communication system without taking either the source or the type
of a mobile access message into consideration. Therefore, the call
origination by the mobile station used by the fire fighter in the
example above or a data burst message from a mobile station used
for system maintenance may be indiscriminately denied access to
current wireless communication systems.
[0007] Because the base station under overload conditions permits
any mobile access up to the capacity of the communication system,
regardless of the importance associated with the mobile access,
non-critical mobile stations or access types may have access to the
communication system over critical or high priority mobile stations
or access types. Therefore, a need exists for a method and an
apparatus for controlling mobile access to a communication system
based upon the availability of system capacity, and prioritizing of
the mobile stations and the access types seeking access to the
communication system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a block diagram representation of a wireless
communication system that may be adapted to operate in accordance
with the preferred embodiments of the present invention.
[0009] FIG. 2 is a block diagram representation of a plurality of
communication cells that may be adapted to operate in accordance
with the preferred embodiments of the present invention.
[0010] FIG. 3 is a flow diagram illustrating a method for
controlling mobile access to a wireless communication system in
accordance with the preferred embodiments of the present
invention.
[0011] FIG. 4 is a block diagram illustrating an apparatus for
controlling mobile access to a wireless communication system in
accordance with the preferred embodiments of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] The present invention provides a method and an apparatus for
controlling mobile access to a communication system via an access
channel by providing control information to mobile stations. A base
station, which provides communication services for mobile stations
in a communication cell, monitors a plurality of mobile access
parameters. In particular, the base station monitors access types
such as registrations only, data burst messages only, and an
aggregate of all mobile accesses originated within the
communication cell, and the rate of the access types. Based on the
rate of the access types, the base station generates control
information to control access to the communication system by
certain mobile stations or type of mobile access.
[0013] The control information generally includes a plurality of
persistence access control parameters that may be, but are not
limited to, a base persistence value and a persistence modifier.
The base persistence value is associated with and identifies the
mobile access overload class of a mobile station and an access
restriction level for all access types in each access overload
class. In particular, an ordinary mobile station used by the
general population belongs to the mobile access overload class in
the range from zero (0) to nine (9), and a mobile station for
special purposes such as emergency or system maintenance belongs to
the mobile access overload class in the range from eleven (11) to
fifteen (15). For example, a mobile station for system maintenance
may receive higher priority for system access than a mobile station
that belongs to the mobile access overload class of eight (8). The
persistence modifier is associated with and identifies the type of
mobile access attempted by the mobile station. Accordingly, the
present invention controls mobile access to the communication
system by generating control information associated with the mobile
access overload class of the mobile station attempting to access
the communication system and the type of the mobile access.
[0014] The base station provides the control information in an
access parameters message via a paging channel to mobile stations
in the communication cell. Prior to an attempt to establish access
to the communication system, a mobile station receives the access
parameters message carrying the control information, and uses the
control information to determine if a mobile access is allowed
based on access type and the current capacity of an access channel.
As a result, certain overload class of mobile stations or type of
mobile access may be denied access to the communication system. For
example, a mobile station with a high priority overload class
attempts to access the communication system in an access channel
overload situation by making an emergency #911 call. The present
invention prevents such a mobile station from being denied service
with other non-critical mobile access attempts originating within
the same communication cell. Therefore, to prevent mobile stations
attempting access from being indiscriminately denied services, the
base station monitors a plurality of mobile access parameters
including access types and the rate of the type of access,
generates control information based on the plurality of mobile
access parameters, and provides the mobile stations within the
communication cell with the control information, from which they
may determine whether to attempt a mobile access based on the
overload class of the mobile stations and the type of the mobile
access attempted by the mobile stations.
[0015] The present invention is described in terms of several
preferred embodiments, and particularly, in terms of a wireless
communication system operating in accordance with at least one of
several communication standards. These standards include analog,
digital or dual-mode communication system protocols such as, but
not limited to, the Advanced Mobile Phone System (AMPS), the
Narrowband Advanced Mobile Phone System (NAMPS), the Global System
for Mobile Communications (GSM), the IS-55 Time Division Multiple
Access (TDMA) digital cellular, the IS-95 Code Division Multiple
Access (CDMA) digital cellular, CDMA 2000, the Personal
Communications System (PCS) and variations and evolutions of these
protocols. As shown in FIG. 1, a wireless communication system 100
includes a mobile switching center (MSC) 110, a plurality of base
station controllers (BSC), generally shown as 120 and 125,
servicing a total service area 130. As is known for such systems,
each BSC 120 and 125 has associated therewith a plurality of base
stations (BS), generally shown as 140, 145, 150, and 155, servicing
communication cells, generally shown as 160, 165, 170, and 175,
within the total service area 130. The MSC 110, BSCs 120 and 125,
and base stations 140, 145, 150, and 155 are specified and operate
in accordance with the applicable standard or standards for
providing wireless communication services to mobile stations (MS),
generally shown as 180, 185, 190, and 195, operating in
communication cells 160, 165, 170, and 175, and each of these
elements are commercially available from Motorola, Inc. of
Schaumburg, Ill.
[0016] As mentioned above, the communication cells 160, 165, 170,
175 in the wireless communication system 100 are divided into a
plurality of sectors. Furthermore, each sector is served by a
different set of channels to provide communication services between
the mobile stations and the base station servicing the
communication cell. Now referring to FIG. 2, the communication
cells, generally shown as 160 and 165, are broken up into a
plurality of sectors, generally shown as 210, 213, 216, 219, 222,
225, and 230, 233, 236, 239, 242, 245, respectively. Similarly, the
communication cells 170 and 175 are broken up into a plurality of
sectors, generally shown as 250, 253, 256, 259, 262, 265, and 270,
273, 276, 279, 282, 285, respectively. Each sector is served by a
channel for communication to and from a base station associated
with the sector. For example, in sector 242 of the communication
cell 165, the mobile station 185 communicates with the base station
145 on a first access channel. Similarly, in sector 236 of the
communication cell 165, the mobile station 190 communicates with
the base station 145 on a second access channel. The access
channels are used for short signaling messages, i.e., mobile access
messages, such as call originations, page acknowledgments, data
burst messages, and registrations, from the mobile stations 185 and
190 to the base station 145. The base station 145 uses first and
second paging channels to communicate with the mobile stations 185
and 190, respectively. The paging channels are used for
transmission of control information, which is further discussed in
details below, and pages from the base station 145 to the mobile
stations 185 and 190. Also, each sector may be associated with a
carrier to form a sector-carrier pair for the base stations and the
mobile stations to communicate with each other.
[0017] In each communication cell of communication system 100
(e.g., communication cell 165), a base station (e.g., base station
145) monitors a plurality of mobile access parameters to provide
communication services to the mobile stations (e.g., mobile
stations 185 and 190) within the communication cell. The plurality
of mobile access parameters are associated with and identify mobile
accesses originated within the plurality of sectors (e.g., sectors
230, 233, 236, 239, 242, 245) of the communication cell. For
example, with respect to communication cell 165, the plurality of
mobile access parameters are associated with the mobile access
originated from the mobile stations 185 and 190 via the first and
second access channels, respectively.
[0018] The plurality of mobile access parameters generally includes
a first mobile access parameter, a second mobile access parameter,
and a third mobile access parameter. In particular, the first
mobile access parameter is associated with all access channel
events such as registrations, data burst messages, page
acknowledgments, and call originations that originated within the
communication cell 165. The first mobile access parameter is used
to control all mobile access traffic that originated from the
mobile stations 185 and 190 within the communication 165. The
second mobile access parameter is associated with registration
traffic only and is used to control registrations. The third mobile
access parameter is associated with data burst message traffic only
and is used to control data burst messages. The base station 145
generates control information based on the plurality of mobile
access parameters. The control information is generated to control
mobile access to the communication system 100 by certain mobile
access overload class or type of mobile access. As mentioned above,
the control information generally includes a plurality of
persistence access control parameters that mobile stations 185 and
190 may use to determine the whether to attempt to access the
communication system 100.
[0019] Accordingly, the base station 145 provides control
information in an access parameter message to the mobile stations
185 and 190 via the first and second paging channels. Prior to
attempting to access the communication system 100 by transmitting a
mobile access message via an access channel allocated to a
respective sector 242, 236 in the communication cell 165, each
mobile station 185, 190 uses the control information to determine
the availability of the communication cell 165, that is, whether
the base station 145 is overloaded and there is a potential of a
failure of the mobile access. Also, each mobile station 185, 190
uses the control information to prioritize the mobile station's
access attempt based on the source and the type of access, that is,
the base persistence value and the persistence modifier,
respectively.
[0020] When the number or rate of mobile accesses exceeds the fixed
access channel capacity, the base station 145 becomes overloaded
and may indiscriminately permit mobile accesses originated within
the sectors 230, 233, 236, 239, 242, 245 of the communication cell
165 unless the mobile access attempts are managed and controlled.
Mobile access is described as indiscriminant in that additional
mobile accesses are permitted as capacity permits without regard to
the mobile classification or type of access request. According to a
preferred embodiment of the invention, each mobile station 185, 190
uses the control information provided by the base station 145 to
determine the condition of the base station 145, i.e., whether it
is presently in an overloaded condition, prior to making an access
attempt. In particular, each mobile station 185, 190 determines the
probability to transmit a mobile access message on an access
channel based on the condition of the sectors 230, 233, 236, 239,
242, and 245 in the communication cell 165, the access overload
class of the mobile station 185, 190, and the type of access being
attempted by the mobile station 185, 190. For example, the mobile
station 185 may belong to a class for special purposes such as
emergency, test, or system maintenance, and the mobile station 190
may be an ordinary mobile station, i.e., the mobile station belongs
to the mobile access overload class in the range from zero (0) to
nine (9). In this case, the mobile station 185 receives higher
priority to request service via an associated access channel than
the mobile station 190.
[0021] In a wireless communication system such as, but not limited
to, a code division multiple access (CDMA) based communication
system, the control information generally includes a plurality of
persistence access control parameters for use by a mobile station
to determine the condition of a base station servicing the mobile
station as one of ordinary skill in the art will readily recognize.
In particular, the plurality of persistence access control
parameters are based on the plurality of mobile access parameters
monitored by the base station. The plurality of persistence access
control parameters generally include, but are not limited to, a
base persistence value and a persistence modifier.
[0022] The base persistence value is associated with the first
mobile access parameter and identifies an access overload class of
a mobile station, which ordinarily corresponds to the last digit of
a mobile station identifier or an international mobile subscriber
identity (IMSI). Typically, mobile stations used by the general
population belong to a mobile access overload class within a range
of zero (0) through nine (9). A base persistence value PSIST(0-9)
is a six-bit value that is used to control mobile access attempted
by mobile stations belonging to the mobile access overload class
within the range of zero (0) through nine (9). Mobile stations for
special purposes such as emergency, test, and system maintenance
belong to a mobile access overload class within a range of ten (10)
through fifteen (15). For example, mobile access overload class ten
(10) is typically associated with and identifies emergency mobile
stations, and mobile access overload class eleven (11) is typically
associated with and identifies test mobile stations. A base
persistence value PSIST(N) is a six-bit value that is used to
control access attempts by mobile stations belonging to the mobile
access overload class within the range often (10) through fifteen
(15).
[0023] The persistence modifiers REG_PSIST and MSG_PSIST are
respectively associated with the second mobile access parameter and
the third mobile access parameter, and identify a mobile access
type that is either a registration or a data burst message,
respectively. In particular, the persistence modifier REG_PSIST,
which is associated with the second mobile access parameter, is a
three-bit value that is used to increase the restriction level
provided by the base persistence value for registration accesses on
the access channel. The persistence modifier MSG_PSIST, which is
associated with the third mobile access parameter, is a three-bit
value that is used to increase restriction level provided by the
base persistence value for data burst messages on the access
channel. Call originations are controlled by the base persistence
value, i.e., PSIST(0-9) or PSIST(N), only. Therefore, in accordance
with a preferred embodiment of the invention, call originations
from a mobile station are less likely to be denied access to the
communication system than a registration or a data burst message
from the same mobile station if the persistence modifier REG_PSIST
or MSG_PSIST values, respectively, are non-zero.
[0024] Prior to making an access attempt, a mobile station, such as
mobile stations 185 and 190, internally generates a pseudorandom
number between zero (0) and one (1) and determines an access value
(P). The access value (P) directly indicates the probability the
mobile station will be permitted to make an access attempt by
transmitting a mobile access message via an access channel. In
particular, the access value (P) is based on one or both of the
base persistence value and the persistence modifier. The
expressions to determine the access value (P) for a mobile station
that belongs to a mobile access overload class with a range from
zero (0) through nine (9), such as mobile station 185, are as
follow:
[0025] (1)P=2.sup.-PSIST(0-9)/4* 2.sup.-REG.sup..sub.--.sup.PSIST
if the access attempt is a registration,
[0026] (2)P=2.sup.-PSIST(0-9)/4* 2.sup.-MSG.sup..sub.--.sup.PSIST
if the access attempt is a data burst message, or
[0027] (3)P=2.sup.-PSIST(0-9)/14 if the access attempt is a call
origination.
[0028] As shown in expression (3), a call origination is restricted
by a base persistence value only. Accordingly, a call origination
from a mobile station has a greater probability of success, i.e.,
less likely to be denied of communication service by the base
station, than a registration or a data burst message. Thus, a call
origination has higher priority than a registration or a data burst
message from the same mobile station.
[0029] The expressions to determine the value P for a mobile
station that belongs to a mobile access overload class (N) with a
range from ten (10) through fifteen (15), such as mobile station
190, are as follow:
[0030] (1)P=2.sup.-PSIST(N)* 2.sup.-REG.sup..sub.--.sup.PSIST if
the mobile access is a registration,
[0031] (2)P=2.sup.-PSIST(N)* 2.sup.-MSG.sup..sub.--.sup.PSIST if
the mobile access is a data burst message, or
[0032] (3)P=2.sup.-PSIST(N) if the mobile access is a call
origination.
[0033] Similar to a call origination by a mobile station that
belongs to a mobile access overload class with a range from zero
(0) through nine (9), a call origination by a mobile station that
belongs to a mobile access overload class (N) with a range from ten
(10) through fifteen (15) is controlled by a base persistence value
only.
[0034] After the access value (P) is determined, it is compared to
the pseudorandom number. If the value P is greater than the
pseudorandom number then the mobile station is permitted to make an
access attempt via the access channel. If the value P is less than
the pseudorandom number then the mobile station waits until a next
opportunity to transmit on the access channel is available and
repeats the process by generating a pseudorandom number again to
determine the value P.
[0035] In accordance with the preferred embodiments of the present
invention, and with references to FIG. 3, a method 300 for
controlling mobile access to a wireless communication system is
shown. Method 300 begins at step 310, where abase station monitors
a plurality of mobile access parameters. In particular, the base
station monitors a first mobile access parameter, a second mobile
access parameter, and a third mobile access parameter. The first
mobile access parameter is associated with all mobile access
traffic that originated from mobile stations within a single sector
in a communication cell serviced by the base station. The second
mobile access parameter is associated with only registration
traffic that originated from mobile stations within the plurality
of sectors in the communication cell. The third mobile access
parameter is associated with only data burst message traffic that
originated from mobile stations within the plurality of sectors in
the communication cell. At step 320, the base station generates
control information based on the plurality of mobile access
parameters. As mentioned above, the control information includes a
plurality of persistence access control parameters, which are based
on the plurality of mobile access parameters. In particular, the
base persistence value, i.e., PSIST(0-9) or PSIST(N), is based on
all of the mobile access parameters. The persistence modifier,
i.e., REG_PSIST or MSG_PSIST, is based on either the second mobile
access parameter or the third mobile access parameter,
respectively. Whether a mobile station is permitted to make an
access attempt through the access channel is based on the access
value P, which is determined by the plurality of persistence access
control parameters. At step 330, the base station provides mobile
stations in the communication cell with an access control message
carrying the control information via a paging channel to control
mobile access to the communication system. Prior to making an
access attempt, at step 340 the mobile stations use the plurality
of persistence access control parameters, i.e., base persistence
value and persistence modifier, in the control information to
determine an access value (P) as described above. The value P is
based on the mobile access overload class of the mobile station
attempting the mobile access and the type of the mobile access.
[0036] Referring to FIG. 4, a base station, such as base stations
140, 145, 150, and 155, is adapted in accordance with a preferred
embodiment of the invention to control mobile access to a
communication system via an access channel. The base station (e.g.,
base station 145) generally includes a receiving unit 410, a mobile
access detector 420, a processor 430, a memory 440, and a
transmitting unit 450. The receiving unit 410 receives mobile
access messages originated from mobile stations (e.g., mobile
stations 185 and 190) in a communication cell (e.g., communication
cell 165) serviced by the base station (i.e., base station
145).
[0037] The mobile access detector 420, which is coupled to the
receiving unit 410 and the processor 430, monitors a plurality of
mobile access parameters including a first mobile access parameter,
a second mobile access parameter, and a third mobile access
parameter. In particular, the first mobile access parameter is
associated with all mobile access traffic including registrations,
data burst messages, page acknowledgments, and call originations
that originated from the mobile stations 185 and 190 in the
communication cell 165. The second mobile access parameter is
associated with only registration traffic that originated from
mobile stations 185 and 190 in the communication cell 165. The
third mobile access parameter is associated with only data burst
message traffic that originated from mobile stations 185 and 190 in
the communication cell 165. The mobile access detector 420 relays
the plurality of mobile access parameters to the processor 430 to
generate control information based on the plurality of mobile
access parameters.
[0038] The memory 440, which is coupled to the processor 430,
stores a program or operating instructions for the processor 430.
The processor 430 executes the program or a set of operating
instructions such that the base station 145 operates in accordance
with a preferred embodiment of the invention. Alternatively, the
program or the set of operating instructions may be embodied in a
computer-readable medium such as, but not limited to, paper, a
programmable gate array, application specific integrated circuit,
erasable programmable read only memory, read only memory, random
access memory, magnetic media, and optical media. In particular,
the control information includes a plurality of persistence access
control parameters.
[0039] The transmitting unit 450, which is coupled to the processor
420, transmits the control information in an access control message
via the paging channels of the communication cell. The mobile
stations 185 and 190 receive the access control message and use the
control information to determine whether they are permitted to make
an access attempt. Accordingly, the mobile stations 185 and 190 are
not indiscriminately denied access by the base station 145.
[0040] Many changes and modifications could be made to the
invention without departing from the fair scope and spirit thereof.
The scope of some changes is discussed above. The scope of others
will become apparent from the appended claims.
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