Apparatus, and associated method, for maintaining a selected quality of service level in a radio communication system

Apparatus, and an associated method, for maintaining a selected QoS (quality of service) level of communications by a mobile station as the mobile station travels throughout an area encompassed by a radio communication system. Subscriber QoS classes are defined. One of the QoS classes is selected pursuant to a service subscription permitting the mobile station to communicate in the radio communication system. The selected QoS class is stored at a service subscription register. During communications with the mobile station, resources are reserved for use by the mobile station at a level corresponding to the selected QoS class.

The present invention relates generally to QoS (Quality of Service) levels 
 of communications in a radio communications system, such as a cellular 
 communication system. More particularly, the present invention relates to 
 apparatus, and an associated method, for maintaining a selected QoS level 
 of communications by a mobile station as the mobile station travels 
 throughout an area encompassed by the radio communication system. 
 Subscriber QoS classes are defined. Different classes of QoS levels assure 
 different levels of QoS as the mobile station moves. When a subscription 
 for service by a user of the mobile station is purchased, the subscription
 rate is, e.g., dependent in part upon the QoS class to which the 
 subscription is made. The amount of resources reserved by the system for 
 communications with the mobile station is dependent upon the QoS class of 
 the service subscription. The amount of resources reserved can also be 
 selected at the start of a communication session. 
 In an exemplary implementation in a cellular communication system, 
 resources, e.g., channels, are selectively reserved for the mobile 
 station, not only in a cell in which communications are ongoing, but also 
 in selected cells proximate thereto. The number of additional cells in 
 which resources are reserved and the duration that the resources are 
 reserved is dependent upon the QoS class. A greater level of mobility 
 independence is thereby available for communications. 
 BACKGROUND OF THE INVENTION 
 The use of wireless communication systems by which to communicate voice and
 data information has achieved wide popularity in recent years. As a wire 
 line connecting a sending station and a receiving station is not required 
 to effectuate communication, communication by way of a wireless 
 communication system is possible at a location to which formation of a 
 wire line connection would be impractical or impossible. 
 A cellular communication system is exemplary of a radio communication 
 system which has achieved wide popularity in recent years. Cellular 
 communication networks of various types of cellular communication systems 
 have been installed throughout significant portions of the world. 
 Subscribers to cellular communications systems are able to communicate 
 telephonically when positioned in areas encompassed by the networks of 
 such systems. Telephonic communication of both voice information and data 
 information are permitted with such networks. 
 A subscriber to a cellular communication network is permitted access to the
 network to communicate therewith pursuant to a service subscription. The 
 service subscription provides, e.g., an identification number which is 
 used to identify uniquely the subscriber, both to permit utilization of 
 the network and also to bill a subscriber for such utilization. 
 Communications originated at, and sometimes terminated at, a mobile 
 station operable pursuant to the service subscription are billed to the 
 subscription account associated with the service subscription. 
 Conventional cellular communication systems are typically mobility 
 dependent. That is to say, during communication set-up, communications 
 with the mobile station are permitted if communication quality levels, 
 i.e., the QoS, of communications between the base station in which the 
 mobile station is positioned and the mobile station is of an acceptable 
 level. However, if the mobile station travels out of the initial cell, and
 into another cell, the QoS of continued communications is not assured. For
 instance, if channels are not available for communications with the mobile
 station in the subsequent cell, a hand-off of communications is not 
 permitted. Deterioration of communication quality is possible, passively 
 resulting in unintended termination of communications. Communication 
 conditions might also change while the mobile station is positioned in the
 initial cell. Therefore, in a conventional, cellular communication system 
 in which QoS is mobility dependent, there are no assurances that a 
 required QoS level can be maintained in an ongoing communication when the 
 mobile station passes from one cell to another or when communication 
 conditions otherwise change. 
 A communication system which, conversely, is mobility independent, would be
 better to assure maintenance of the required QoS level as a mobile station
 moves from one cell to another or when communication conditions otherwise 
 change. 
 A manner by which to provide a radio communication system, such as a 
 cellular communication system, with mobility-independent QoS would 
 therefore be advantageous. 
 It is in light of this background information related to radio 
 communication systems, and QoS levels therein, that the significant 
 improvements of the present invention have evolved. 
 SUMMARY OF THE INVENTION 
 The present invention, accordingly, advantageously provides apparatus, and 
 a corresponding method, for maintaining a selected QoS level of 
 communications with the mobile station in a radio communication system. By
 maintaining the selected QoS level, a selected level of 
 mobility-independent QoS is better assured. 
 In one aspect of the present invention, subscriber QoS classes are defined.
 Different classes of QoS levels correspond to different levels of 
 mobility-independent QoS of ongoing communications with a mobile station 
 as the mobile station travels throughout a geographical area encompassed 
 by the radio communication system. A user of the mobile station purchases 
 a subscription for service to permit communications through a mobile 
 station with network infrastructure of the radio communication system. The
 subscription rate of the service subscription is dependent, in part, upon 
 the class of QoS to which the subscription is made. The amount of 
 resources reserved by the system for use to communicate with the mobile 
 station is dependent upon the QoS class of the service subscription. The 
 amount of resources reserved can also be selected at the start of a 
 communication session. Such selection overrides the stored values of the 
 QoS class. 
 In another aspect of the present invention, mobility-independent QoS is 
 provided to cellular communications in a cellular communication system. 
 When a service subscription is purchased, the subscriber of the 
 subscription is permitted to communicate with the cellular network through
 a mobile station. When the service subscription is purchased, a selection 
 is made of a subscriber QoS class (SQC). The SQC corresponds to a QoS 
 level that is to be maintained during communications with a mobile station
 through which communications are to be effectuated pursuant to the service
 subscription. Resources are reserved for communication with the mobile 
 station, not only in the cell in which the mobile station is presently 
 located, but also at one or more additional cell to which the mobile 
 station might travel during a communication session. The amount of 
 resources reserved by the system is dependent upon the SQC class to which 
 the subscriber subscribes. At higher SQC classes, greater levels of 
 resources are reserved. 
 In one implementation, SQCs are defined in a cellular communication system 
 constructed to correspond to the standards of the IS-95 3G system. In such
 system, the cells defined by the base stations of the network 
 infrastructure of the system are defined, relative to a mobile station, to
 be of one of four different sets of cells. Namely, the cells are defined 
 to be members of an active set, a candidate set, a neighbor set, or a 
 remaining set. The cells sets are dynamically redefined, with respect to 
 the mobile station, as the mobile station moves through the geographical 
 area encompassed by the communication system. The SQCs are defined 
 relative to the sets defined in the IS-95 3G system. In one 
 implementation, a first class SQC allocates resources only in the active 
 set of cells. Higher-levels of SQCs further reserve resources in at least 
 selected ones of the candidate set of cells. And, in still higher levels 
 of SQCs, additional resources are reserved in at least selected ones of 
 the neighbor set of cells. Further differentiation between the various 
 classes of cells is provided by the start times at which the resources are
 reserved in the various cell sets, and the duration periods during which 
 such resources are reserved. 
 In other implementations, for instance, in cellular communication systems 
 constructed according to analog or TDMA (time division multiple access) 
 standards, analogous SQCs are defined. In a TDMA system, as well as an 
 analog system, cells are classified in manners analogous to the 
 classifications of the cells to be members of active, candidate, and 
 neighbor sets designated in the IS-95 3G standard. An SQC is selected by a
 subscriber pursuant to the subscriber's purchase of a service 
 subscription. Subsequent to call origination, or termination, at the 
 mobile station operable pursuant to the service subscription, resources 
 are reserved by the cellular system responsive to the selected SQC. 
 In these and other aspects, therefore, apparatus, and an associated method,
 is provided for maintaining a selected QoS (quality of service) of 
 communications of a mobile station. The mobile station is operable in a 
 multi-user, radio communication system having a fixed network including a 
 plurality of spaced-apart, fixed-site transceivers positioned throughout a
 geographic area. Each fixed-site transceiver defines a coverage area in 
 which communications with a mobile station are permitted pursuant to a 
 service subscription. The selected QoS is maintained as the mobile station
 travels throughout the geographic area encompassed by the radio 
 communication system. A service subscription register is associated with 
 the mobile station. The service subscription register stores an indication
 of a selected QoS level of which communications with the mobile station 
 are to be maintained. The indication of the selected QoS level is indexed 
 together with an identifier which identifies the mobile station. A 
 resource reserver is coupled to receive information representative of the 
 indication of the selected QoS level stored at the service subscription 
 register. The resource reserver is also coupled to the plurality of 
 spaced-apart, fixed-site transceivers. The resource reserver selectively 
 reserves resources at selected ones of the fixed-site transceivers for 
 communications by the mobile station. The resources are caused to be 
 selectively reserved, and the time periods during which the resources are 
 caused to be selectively reserved, are responsive to the QoS level 
 associated with the mobile station. The resources reserved by the resource
 reserver assures that the selected QoS level of the communications by the 
 mobile station is available to the mobile station. 
 A more complete appreciation of the present invention and the scope thereof
 can be obtained from the accompanying drawings which are briefly 
 summarized below, the following detailed description of the 
 presently-preferred embodiments of the invention, and the appended claims.

DETAILED DESCRIPTION 
 Referring first to FIG. 1, a portion of a cellular communication system 
 shown generally at 10, permits telephonic communications with wireless 
 transceivers, of which the mobile station (MS) 12 is representative. The 
 system 10 is here representative of the cellular communication system 
 defined in the IS-95 3G specification standard promulgated by the EIA/TIA.
 Other cellular communication systems, and other radio communication 
 systems, can be analogously represented. 
 The portion of the system 10 illustrated in the FIG. includes a plurality 
 of cells 14. Each of the cells 14 is defined by a radio base station 16. 
 The radio base stations 16 form fixed-site transceivers positioned at 
 spaced-apart locations throughout the geographical area encompassed by the
 communication system 10. For purposes of illustration, the base stations 
 16 are positioned at the centers of the cells 14 which are defined by the 
 individual ones of the base stations 16. In actual implementations, other 
 arrangements are possible. For instance, through the use of sector 
 antennas, three base stations may be co-located, and cells defined by the 
 base stations may be defined by the sectors of coverage of such sector 
 antennas. 
 The cells 14 of the system 10 are further designated by the set definitions
 defined in the IS-95 3G standard. That is to say, the cells 14, relative 
 to the mobile station 12 are dynamically determined to be members of one 
 of four sets of cells, namely an active set, a candidate set, a neighbor 
 set, and a remaining set. 
 Cells 12 of the active set are designated by the designation A. Here, three
 cells 12 are members of the active set, cells A1, A2, and A3. Cells 12 
 defined to be members of the active set are the cells having pilot signals
 associated with forward traffic channels assigned for communications with 
 the mobile station 12. 
 Cells 14 of the candidate set are designated by the designation C. Here, 
 five cells 14 are members of the candidate set, cells C1, C2, C3, C4, and 
 C5. Cells 14 defined to be members of the candidate set are the cells 
 having pilot signals that are not currently members of the active set but 
 in which the pilot signals have been received by the mobile station 12 
 with sufficient strength to indicate that the forward traffic channels 
 associated with such cells could be used for communications. 
 Cells 14 of the neighbor set are designated by the designation N. Here, 
 five cells N are members of the neighbor set, cells N1, N2, N3, N4 and N5.
 Cells 14 defined to be members of the neighbor set are the cells having 
 pilot signals of characteristics not to be included in the active set or 
 the candidate set, and are not likely candidates for hand over of 
 communications as the mobile station 12 travels through the communication 
 system 10. 
 Cells 14 of the remaining set are designated by the designation R. Cells 14
 defined to be members of the remaining set are those cells which do not 
 form members of the active, candidate, or neighbor sets. 
 The members of the cell sets are dynamically redefined as the mobile 
 station 12 travels or the communication conditions of the traffic channels
 otherwise change. The assignation of cells to various sets shown in the 
 FIG. is exemplary. Generally though, cells of the active set are typically
 cells positioned most proximate to where the mobile station 12 locates. 
 Generally also, cells of the candidate set are cells, outward of the cells
 of the active set, but still close to the mobile station 12. Cells of the 
 neighbor set are generally cells adjacent to those of the candidate set, 
 but farther away from the mobile station 12. And, cells of the remaining 
 set are generally those located far away from the mobile station. 
 In this type of cell classification, and as indicated in the exemplary 
 illustration, the mobile station 12 is here currently active at a location
 encompassed by the active set of cells and is likely to move, such as in 
 the direction indicated by the arrow 18, into a cell of the candidate set 
 of cells at a time, dependent upon the speed and direction of the mobile 
 station. By utilizing movement prediction techniques, it is possible to 
 predict with some likelihood a subset of the cells of the candidate set 
 are more likely into which the mobile station 12 shall travel. 
 The base stations 16 are coupled to base station controllers, of which the 
 base station controller (BSC) 22 is exemplary. Typically, several base 
 stations are coupled to, and are controlled by, a single BSC. Each BSC is 
 coupled to a mobile switching center (MSC), of which the MSC 24 is 
 exemplary. Typically, several BSCs are coupled to a single MSC. Each MSC, 
 in turn, is coupled to a PSTN (public-switched telephonic network). 
 According to an embodiment of the present invention, the BSCs, such as the 
 BSC 22 include a resource reserver 26. And, the MSC 24 is shown further to
 include an HLR (home location register) 28. A portion of the HLR 28 is 
 formed of a service subscription register 32. 
 In conventional manner, the mobile station 12 is associated with an HLR, 
 here the HLR 28. The HLR stores data associated with the mobile station. 
 The service subscription register 32, forming a portion of an embodiment 
 of the present invention, is used to store subscription information 
 related to the subscription pursuant to which the mobile station 12 is 
 operable. Here, in particular, the service subscription register 32 stores
 data related to the SQC (subscriber quality of service) purchased pursuant
 to the service subscription of the mobile station 12. The level of 
 mobility-independence, i.e., the amount of resources reserved for 
 communications by the mobile station, is dependent upon the level of SQC 
 of the service subscription. During communication set-up, or thereafter, 
 the data stored at the service subscription register 32 is accessed. 
 Responsive to the data accessed at the service subscription register, the 
 resource reserver 26 associated with the BSCs reserve resources for 
 communications by the mobile station. A selected level of QoS (quality of 
 service) is assured for communications with the mobile station 12 to 
 provide thereby a selected level of mobility independence. The data stored
 at the service subscription register 32 of the HLR 28 can be transferred, 
 in convention fashion, to a VLR (visited location register) such as when 
 the mobile station 12 is in the roaming mode. User selection of a QoS 
 class can also be made for a particular communication session. Such 
 selection overrides the stored values stored at the register 32. 
 FIG. 2 illustrates, in tabular form, the data stored at the service 
 subscription register 32 pursuant to an embodiment of the present 
 invention. Here, the mobile station 12 is identified by an IMEI 
 (international mobile station equipment identity) 38. 
 Subscription-specific data, here including an indication of the SQC 42 
 associated with the mobile station, is indexed against the IMEI 38. The 
 SQC associated with the mobile station 12 is provided to the resource 
 reserver 26 and the appropriate resources are reserved for communications 
 by the mobile station to provide the mobile station with a selected level 
 of mobility-independence. The indications of the SQCs 42 form a default 
 SQC. In an exemplary implementation, a subscriber is able to select an 
 alternate SQC at each service initiation. 
 In an exemplary implementation, six SQCs are defined. The different classes
 of SQC are determinative of the level of mobility-independence provided to
 communications by the mobile station 12. While the resources reserved for 
 communications by the mobile station 12 are dependent upon the SQC 
 associated with the mobile station, the resources reserved for such 
 communications are dynamically determined. That is to say, as conditions, 
 or the position of the mobile station changes, the resources reserved for 
 communications with the mobile station are dynamically reallocated. 
 FIG. 3 illustrates graphically a first SQC defined according to an 
 embodiment of the present invention. The first class is designated as 
 Class 1. In the graphical representation, the time period during which a 
 resource is allocated to the mobile station 12 is scaled along the 
 abscissa axis 46. And, the cells at which resources are reserved are 
 defined along the ordinate axis 48. When the subscription calls for class 
 1 QoS, resources of only the active set are allocated for the mobile 
 station, as indicated by the bar 50. In this implementation, class 1 forms
 a default class and provides the least mobility-independence of the 
 various SQCs. Resources are reserved at the cells of the active set 
 starting at a start time, T.sub.start.sub..sub.-- .sub.active, indicated 
 at 52, and extending until an ending time T.sub.end.sub..sub.-- 
 .sub.active, indicated at 54. The time 54 might be the termination of a 
 communication session. The time 54 might also be the time when a 
 particular cell is no longer an active cell, such as when a handover 
 occurs. 
 FIG. 4 represents a second SQC, here designated Class 2. The abscissa and 
 ordinate axes 46 and 48 are the same as those shown in FIG. 3. Here, 
 resources are allocated not only at the cells of the active set, indicated
 by the bar 50, but also at selected cells of the candidate set, here cells
 C1, C2 and C5, indicated by the bar 58. In an exemplary implementation, 
 the cells C1, C2 and C5 of the candidate set are selected pursuant to 
 movement predication analysis of the mobile station to reduce the number 
 of cells of the candidate set at which resources are allocated for 
 communications by the mobile station. Again, the bar 50 indicates that the
 resources are reserved at the cells of the active set starting at the 
 T.sub.start.sub..sub.-- .sub.active time 52 and extending until the 
 T.sub.end.sub..sub.-- .sub.active time 54. For the class 2 QoS, and as 
 indicated by the block 58, resources are allocated at the cells of the 
 candidate set starting at a selected delay relative to the 
 T.sub.start.sub..sub.-- .sub.active time 52, here the time 
 T.sub.start.sub..sub.-- .sub.candidate 62 and extending for a selected 
 duration, here a duration D.sub.candidate indicated by the time 64. The 
 time 62 is, in one embodiment, a selected, fixed time delay relative to 
 the T.sub.start.sub..sub.-- .sub.active, time 52. In another embodiment, 
 the delay period and also the reservation duration are dynamically 
 determined, responsive to the characteristics of the mobile station, such 
 as its velocity. 
 FIG. 5 represents a third SQC, here designated class 3. The abscissa and 
 ordinate axes 46 and 48 are scaled as noted previously. The bar 50 again 
 indicates that resources are reserved at the cells of the active set 
 starting at the T.sub.start.sub..sub.-- .sub.active time 52 and extending 
 to the T.sub.end.sub..sub.-- .sub.active time 54 of termination of the 
 communication session. Here, the bar 68 indicates that resources are 
 reserved at selected cells, again cells C1, C2, and C5 of the candidate 
 set. Here, the resources are reserved starting at the time 62, but 
 extending until the T.sub.end.sub..sub.-- .sub.active time 54. 
 FIG. 6 illustrates a fourth SQC, here designated Class 4. The abscissa and 
 ordinate axes 46-48 are again illustrated, and the bars 50 and 58 are 
 again illustrated to indicate resources reserved in the cells of the 
 active set and selected cells of the candidate set, respectively. The bar 
 50 indicates again that the resources are reserved as the cells of the 
 active set starting at the T.sub.start.sub..sub.-- .sub.active time 52 and
 extending until the T.sub.end.sub..sub.-- .sub.active time 54. And, the 
 bar 58 again indicates the resources are reserved at the selected cells of
 the candidate set starting at time 62 and extending until time 64. When 
 the QoS level corresponds to the Class 4 SQC, resources are also reserved 
 at selected cells of the neighbor set, here cells N1 and N5. The bar 72 
 represents the reservation of the resources at the selected cells of the 
 neighbor set. Here, the resources are reserved at the time 74 for a 
 duration extending until the time 64. The time 74 is of a second time 
 delay relative to the T.sub.start.sub..sub.-- .sub.active time 52 and here
 is of a time delay greater than the time delay extending to the start time
 62. The delay period and the reservation period in the neighbor set is 
 also dynamically determined. 
 FIG. 7 illustrates a fifth SQC, here designated Class 5. Again, the 
 abscissa and ordinate axes 46 and 48 are shown, and the bars 50 and 68 
 represent resources reserved at the cells of the active set and selected 
 ones of the candidate set respectively. The T.sub.start.sub..sub.-- 
 .sub.active time 52, the T.sub.end.sub..sub.-- .sub.active time 54, and 
 the start time 62 again indicates the times at which the resources are 
 reserved at the selected cells of the candidate set. The resources are 
 reserved at the cells of the candidate set until T.sub.end.sub..sub.-- 
 .sub.active at time 54. Here, resources are reserved at selected cells, 
 again cells N1 and N5, of the neighbor set for a period indicated by the 
 bar 82. The start time at which the resources are reserved at the cells of
 the neighbor set is again time 74. Here, the duration of the period during
 which the resources are reserved extends until time 84. 
 FIG. 8 illustrates a sixth SQC, designated Class 6. Here again, the 
 abscissa and ordinate axes 46-48 are shown, and the bars 50 and 68 
 illustrate the resources reserved at the active set and selected ones of 
 the candidate set, respectively. The resources are reserved at the cells 
 of the active set starting at the T.sub.start--active time 52 and 
 extending until T.sub.end.sub..sub.-- .sub.active time 54. And, the bar 68
 indicates that the resources are reserved at the cells of the candidate 
 set starting at time 62 and extending until the T.sub.end.sub..sub.-- 
 .sub.active time 54. Here, the resources are reserved at the selected 
 cells of the neighbor set for time period indicated by the bar 92. Again, 
 movement prediction techniques are utilized to reduce the number of cells 
 of the neighbor set at which resources need be reserved to assure a 
 selected level of mobility-independence. 
 Here, the start time at which the resources are reserved at the cells of 
 the neighbor set is indicated at the time 74, and the duration during 
 which the resources are reserved at the cells of the neighbor set extends 
 until T.sub.end.sub..sub.-- .sub.active time 54. The time delay of the 
 time 74 relative to the T.sub.start.sub..sub.-- .sub.active time 52 is 
 again, in one embodiment, a fixed time duration, and in another 
 embodiment, such time delay is dynamically determined responsive to 
 characteristics of the mobile station, again, e.g., the velocity of the 
 mobile station. 
 The Classes 1-6 of QoS levels represented in the FIGS. 3-8 illustrate that 
 any of a plurality of levels of mobility-independence can be selected 
 pursuant to a service subscription. Responsive to the selected SQC, an 
 appropriate level of mobility-independence is provided to the user of a 
 mobile station to assure better that the QoS levels required by the 
 subscriber are maintained. 
 While the exemplary implementation illustrates six classes of QoS levels, 
 analysis of the graphical representations of FIGS. 3-8 indicates that 
 there are two variables in the QoS class definition. Namely, the starting 
 time of the reservation of the resources and the duration that the 
 resources are reserved, T and D, respectively, are determinative of the 
 resource reservations. Each starting time and each duration during which 
 the resources are reserved at selected cells of any of these sets of cells
 can either be specified, i.e., fixed, or can be dynamically determined. If
 dynamic determinations of the starting times and durations are utilized, 
 movement prediction techniques including e.g., the mobile station's 
 history and its velocity, network deployment, and resource availability 
 can be used to make such determinations. 
 FIG. 9 illustrates a method, shown generally at 102, of the method of an 
 embodiment of the present invention. The method 102 maintains a selected 
 QoS level of communications between a mobile station and a fixed network. 
 The fixed network includes a plurality of spaced-apart, fixed-site 
 transceivers positioned throughout a geographic area. First, and as 
 indicated by the block 104, an indication of a selected QoS level of which
 communications with the mobile station are to be maintained are stored. 
 Then, and as indicated by the block 106, resources are selectively 
 reserved at selected ones of the fixed-site transceivers for 
 communications by the mobile station. The amount of resources caused to be
 reserved, and time periods during which the resources are reserved, is 
 responsive to the QoS level associated with the mobile station. Thereby, 
 an appropriate QoS level of communications by the mobile station is 
 assured. 
 Thereby, through operation of an embodiment of the present invention, a 
 selected QoS level of communications by a mobile station as the mobile 
 station travels throughout a geographic area encompassed by a radio 
 communication system is assured. Selected QoS levels are purchased 
 pursuant to a service subscription or the QoS level is selected by a user 
 at the start of a communication session. The amount of resources reserved 
 by the system for use to communicate with the mobile station is dependent 
 upon the QoS class of the service subscription. 
 The previous descriptions are of preferred examples for implementing the 
 invention, and the scope of the invention should not necessarily be 
 limited by this description. The scope of the present invention is defined
 by the following claims.