Abstract:
A method and apparatus for sequential measurement reporting in media independent handover communications are disclosed. In a first embodiment a measurement time field is added to existing IEEE 802.21 measurement report messages. In a second embodiment a measurement sequence number field is added to existing IEEE 802.21 measurement report messages. Optionally, the measurement time field, or sequence number field may be included in an IEEE 802.21 message.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Provisional Application No. 60/942,546, filed on Jun. 7, 2007 which is incorporated by reference as if fully set forth. 
     
    
     FIELD OF INVENTION 
       [0002]    This application is related to wireless communications. 
       BACKGROUND 
       [0003]    The IEEE 802.21 Media Independent Handover standard defines mechanisms and procedures that aid in the execution and management of inter-access technology mobility management. IEEE 802.21 defines three main services available to Mobility Management applications. Referring to  FIG. 1 , these services are the Event Service  100 , the Information Service  105  and the Command Service  110 . These services aid in the management of handover operations, system discovery and system selection by providing information and triggers from lower layers  115  to upper layers  120 , and lower layer commands from upper layers  120  to lower layers  115  via a media independent handover (MIH) function (MIHF)  125 . While  FIG. 1  shows MIHF  125  as a middle layer in a protocol stack, MIHF  125  may also be implemented as an MIH plane that is capable of exchanging information and triggers directly with each and every layer of a technology specific protocol stack. 
         [0004]    Events may indicate changes in state and transmission behavior of the physical, data link and logical link layers, or predict state changes of these layers. The Event Service  100  may also be used to indicate management actions or command status on the part of the network or a management entity. The command service  110  enables higher layers to control the physical, data link, and logical link layers (referred to collectively as lower layers). The higher layers may control the reconfiguration or selection of an appropriate link through a set of handover commands. If a MIHF supports the command service, all MIH commands are mandatory in nature. When an MIHF receives a command, it is always expected to execute the command. The Information Service  105  provides a framework and corresponding mechanisms by which a MIHF entity may discover and obtain network information existing within a geographical area to facilitate handover. 
         [0005]    IEEE 802.21 has defined several messages for periodically providing measurement reports. For example the link parameters report provides periodic measurements to other MIFH entities. However, the link parameters report does not provide any indication as to when a measurement was made, or the report was sent. An entity receiving these reports will therefore be unable to ensure that the measurements were received in the order they were made. Accordingly there is a need to provide a mechanism to indicate a sequence or time indicator with each measurement report. Similarly, there is a need to ensure that all IEEE 802.21 messages are received in the correct order. 
       SUMMARY 
       [0006]    A method and apparatus for sequential measurement reporting are disclosed. In a first embodiment a measurement time field is added to existing IEEE 802.21 measurement report messages. In a second embodiment a measurement sequence number field is added to existing IEEE 802.21 measurement report messages. Optionally, the measurement time field, or sequence number field may be included in an IEEE 802.21 message. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings wherein: 
           [0008]      FIG. 1  is an IEEE 802.21 protocol architecture according to the prior art; 
           [0009]      FIG. 2  shows the implementation of a mobile device and network supporting MIH functions; 
           [0010]      FIG. 3  shows an example of a IEEE 802.21 message frame format including a Measurement Time Field; and 
           [0011]      FIG. 4  shows an example of a IEEE 802.21 message frame format including a Measurement Sequence Field. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    When referred to hereafter, the terminology “wireless transmit/receive unit (WTRU)” includes but is not limited to a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a computer, or any other type of media independent handover device. When referred to hereafter, the terminology “base station” includes but is not limited to a Node-B, a site controller, an access point (AP), or any other type of interfacing device capable of operating in a wireless environment. 
         [0013]      FIG. 2  is a block diagram of a wireless communication system  200  which includes a wireless transmit/receive unit  205  and an AP  1210 . The WTRU  205  and the AP  210  communicate via a wireless communication link,  212 . 
         [0014]    As shown in  FIG. 2 , the WTRU  215  includes an MIHF  215 , a processor  220 , at least one transceiver ( 225   a ,  225   b ), and a measurement unit  227 . The processor  220  is attached to the MIHF  215  and each of the transceivers  225   a ,  225   b . The measurement unit  227  is attached to the processor  220  and the MIHF  215  and is configured to periodically perform measurements on various link parameters. The MIHF  215  is configured to carry out media independent handover related processes, including generating MIH measurement report messages which include measurement information and an associated time stamp or sequence number. Optionally, the MIHF  215  is also configured to generate any type of IEEE 802.21 message with an associated time stamp or sequence number. 
         [0015]    Also shown in  FIG. 2 , the AP  210  includes an MIHF  230 , a processor  235 , at least one transceiver ( 240   a ,  240   b ). The processor  235  is attached to the MIH function  215  and each of the transceivers  225   a ,  225   b . The MIHF  230  is configured to carry out media independent handover related processes, processing measurements reports received by the transceiver and assembling them in order based on the time stamp or sequence number. Optionally, the MIHF  230  may be located outside of the AP  210  in the network (not shown). For example, the AP  210  may be connected to an access router (not shown) which may house the MIHF  230 . 
         [0016]      FIG. 3  is an example measurement report message  300  which may be generated and transmitted by the communication entities of  FIG. 2 . For the purpose of example, the measurement report message  300  includes an MIH Header Field  310 , a Source Identifier field  320 , a Destination Identifier field  330 , a Transaction Identifier field  340 , a Link Identifier field  350 , a Measurement Time field  360 , and a Link Parameter field  370 . One of skill in the art would recognize that the disclosed Measurement Time field  360  could also be applied to any other type of IEEE 802.21 message, such as other Link event messages, Command messages, and Information service messages 
         [0017]    The MIH Header field  310  carries the essential information that is present in every frame and is used for parsing and analyzing the MIH protocol frame and the Transaction Identifier field that is used for matching request, response and acknowledgement messages. The Source Identifier field  320  indicates the identity of the MIHF which sent the message. The Destination Identifier field  330  indicates the identity of the destination MIHF. The Link Identifier field indicates the link associated with the event. The Measurement Time field  360  indicates the time at which a measurement report message is related. The Link Parameter Status List field  370  contains the event-related information that is being reported 
         [0018]    The Measurement Time field  360  may represent either an absolute time measurement or a time measurement relative to a to another known time. Table 1 shows an example of a possible definition for the Measured Time field  360 . In Table 1 the measured time is represented using five octets, where the first octet represents the hour, the second octet represents the minute, the third octet represents seconds, and the forth and fifth octets are used in a union to represent milliseconds. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Type Name 
                 Derived From 
                 Definition 
                 Valid Range 
               
               
                   
               
             
             
               
                 TIME —   
                 e.g. 
                 Represents 5 octets, 
                 First octet: 
               
               
                 STAMP 
                 LIST(CHAR(5)) 
                 with the first for 
                 00-23 
               
               
                   
                   
                 hour, second for 
                 Second octet: 
               
               
                   
                   
                 minute, third for 
                 00-59 
               
               
                   
                   
                 seconds and fourth 
                 Third octet: 
               
               
                   
                   
                 and fifth used in a 
                 00-59 
               
               
                   
                   
                 union for 
                 Fourth and fifth 
               
               
                   
                   
                 milliseconds. 
                 octet union: 
               
               
                   
                   
                   
                 000-999 
               
               
                   
               
             
          
         
       
     
         [0019]    In an alternative embodiment, Table 2 shows an example of a possible definition for the Measured Time field  360 . In Table 2 the measured time is represented as four octets, where the first octet represents the hour, the second octet represents the minute, and the third and forth octets are used in a union to represent milliseconds. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Type Name 
                 Derived From 
                 Definition 
                 Valid Range 
               
               
                   
               
             
             
               
                 TIME —   
                 e.g. 
                 Represents 4 octets, 
                 First octet: 
               
               
                 STAMP 
                 LIST(CHAR(4)) 
                 with the first for 
                 00-23 
               
               
                   
                   
                 hour, second for 
                 Second octet: 
               
               
                   
                   
                 minute, third and 
                 00-59 
               
               
                   
                   
                 fourth in a union 
                 Third and fourth 
               
               
                   
                   
                 for milliseconds. 
                 octet union: 
               
               
                   
                   
                   
                 00000-59999 
               
               
                   
               
             
          
         
       
     
         [0020]    In another alternative embodiment, Table 3 shows an example of a possible definition for the Measured Time field  360 . In Table 3 the measured time is represented as two or more octets showing a differential in time in milliseconds between the measurement and known reference point, such as registration, or previous measurement. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                 Type Name 
                 Derived From 
                 Definition 
                 Valid Range 
               
               
                   
               
             
             
               
                 TIME —   
                 e.g. 
                 Represents 2 (or 
                 0-65535 (if two 
               
               
                 STAMP 
                 INTEGER(2) 
                 more) octets to 
                 octets are used) 
               
               
                   
                   
                 show time in e.g. 
               
               
                   
                   
                 milliseconds from a 
               
               
                   
                   
                 reference point 
               
               
                   
                   
                 (e.g. registration, 
               
               
                   
                   
                 first measurement 
               
               
                   
                   
                 report, some 
               
               
                   
                   
                 defined event or 
               
               
                   
                   
                 some fixed time) 
               
               
                   
               
             
          
         
       
     
         [0021]    In another alternative embodiment, Table 4 shows an example of a possible definition for the Measured Time field  360 . In Table 4 the measured time is represented as two or more octets to show a central processing unit (CPU) clock time of a sending peer defined in Time Units (TU), which could be defined as multiples of ms, μs, etc. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
               
                 Type Name 
                 Derived From 
                 Definition 
                 Valid Range 
               
               
                   
               
             
             
               
                 TIME —   
                 e.g. 
                 Represents 2 (or 
                 0-65535 (if two 
               
               
                 STAMP 
                 INTEGER(2) 
                 more) octets to show 
                 octets are used) 
               
               
                   
                   
                 CPU clock time (in 
               
               
                   
                   
                 suitable units, e.g. 
               
               
                   
                   
                 ms, μs, TU, etc.) of 
               
               
                   
                   
                 the sending peer 
               
               
                   
               
             
          
         
       
     
         [0022]      FIG. 4  shows an example measurement report message  400  which may be generated and transmitted by the communication entities of  FIG. 2 . For the purpose of example, the measurement report message  400  includes an MIH Header Field  310 , a Source Identifier field  420 , a Destination Identifier field  430 , a Link Identifier field  450 , a Measurement Sequence field  360 , and a Link Parameter field  470 . One of skill in the art would recognize that the disclosed Measurement Sequence field  460  could also be applied to any other type of measurement report message, such as other Link event messages, Command messages, and Information service messages. 
         [0000]                                TABLE 5               Type Name   Derived From   Definition   Valid Range                   SEQUENCE   e.g.   Represents   0-65535           INTEGER(2)   sequence of any               event such as               measurement               report.                    
Table 5 shows an example of a possible definition for the Sequence field  460 . The Sequence field  460  will be a number which represents a sequence of each event such as each measurement or each measurement report. The Sequence field  460  allows holes in received messages to be detected as missing numbers in the sequence. Any dropped event or message can be detected by the AP  210 . Optionally, the additional information provided or derived by from the Sequence  460  field may be applied to a handover algorithm.
 
         [0023]    Although features and elements are described above in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements. The methods or flow charts provided herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable storage medium for execution by a general purpose computer or a processor. Examples of computer-readable storage mediums include a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). 
         [0024]    Suitable processors include, by way of example, a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and/or a state machine. 
         [0025]    A processor in association with software may be used to implement a radio frequency transceiver for use in a wireless transmit receive unit (WTRU), user equipment (UE), terminal, base station, radio network controller (RNC), or any host computer. The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, a Bluetooth® module, a frequency modulated (FM) radio unit, a liquid crystal display (LCD) display unit, an organic light-emitting diode (OLED) display unit, a digital music player, a media player, a video game player module, an Internet browser, and/or any wireless local area network (WLAN) or Ultra Wide Band (UWB) module.