Abstract:
The invention relates to a system and method for use in wireless packet data mode communications for enabling communication between a source device ( 102   a ) and one or more target devices ( 102   b ) with a reduced set-up time. The invention captures in a control structure ( 600 ), one or more communication parameters ( 602 - 608 ) during the set up of the source device ( 102 ) and a base station ( 106 ). Then the control structure( 600 ) is transmitted to the one or more target devices ( 102   b ) during the period of the source device&#39;s ( 102   a ) configuration and is utilized to configure the one or more target devices ( 102   b ) to communicate with the source device( 102   a ) via the base station ( 106 ), thus reducing the total time required to set-up the communications.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to wireless system communications. More particularly, the invention relates to the reduction of the set-up time for remote units utilizing packet data as opposed to switched data to communicate with a base station.  
         BACKGROUND OF THE INVENTION  
         [0002]    The wireless industry has grown at a tremendous pace over the past few years. Wireless communication has become a standard part of every day life. Most people utilize some derivative form of wireless communications such as Global System for Mobile communication (GSM), Universal Mobile Telecommunications System (UMTS), Carrier Detection Multiple Access (CDMA) and 802.11 in various aspects of daily living.  
           [0003]    Generally, radio systems are designed for a certain area of coverage or footprint. These areas are generally referred to as cells. Cells enable the reuse of similar frequencies by multiple sources to support services in metropolitan areas that are some distance apart. The geographic size of cells are not necessarily consistent throughout a given area and may vary due to frequency and power level, topography of the area, time of day and so forth. Communications within these cells take advantage of a concept known as Demand Assigned Multiple Access (DAMA). DAMA enables multiple devices to access a network in a shared manner on a demand basis. Basically, devices access the network on a first come, first serve basis. Within a wireless network, there are a number of ways in which multiple access can be provided to end-users. At the most basic level, there is a Frequency Division Multiple Access (FDMA) methodology, which is essentially the starting point for all wireless communications, given that each cell must be separated by frequencies to avoid interferences among wireless devices. FDMA divides assigned frequency ranges into multiple carrier frequencies in order to support multiple conversations.  
           [0004]    Another method that is utilized in wireless networking is the Time Division Multiple Access (TDMA), which is a digital technique that divides each frequency channel into multiple time slots. Each of the time slots within a frequency channel supports an individual device conversation. Generally speaking, services based on TDMA offer roughly three times the traffic capacity of FDMA services.  
           [0005]    Yet another communication methodology, which is relatively new and has its root in spread spectrum radio is known as Code Division Multiple Access (CDMA). Spread spectrum radio spreads the bandwidth of a transmitted signal over a spectrum of radio frequencies. The combined spectrum of radio frequencies is usually much wider than what is required to support the narrow band transmission of the signal. Spread spectrum uses two techniques namely, Direct Sequence (DS) and Frequency Hopping (FH). In brief, direct sequence spread spectrum is a packet radio technique in which the narrow band signal is spread across a wider carrier frequency band. In other words, the signal information is organized into packets, each of which is transmitted across a wider carrier band frequency in a redundant manner i.e. packets are sent more than once. Multiple transmissions can then be supported. The transmissions from specific terminals are identified by a unique code such as, a  10  bit code that is pre-pended to each data packet. Frequency Hopping Spread Spectrum is generally preferred over direct sequence spread spectrum. FHSS involves transmission of short bursts of packets within the wide band carrier over a range of frequencies. Essentially, the transmitter and receiver hop from one frequency to another in a choreographed hop sequence and a number of packets are sent to each frequency. The hop sequence is controlled by a centralized base station antennae.  
           [0006]    Regardless of the communication methodology for a given network, a certain amount of pre-configured set-up and real time set-up of communication devices will be required. One such requirement for communication between a remote/mobile unit and a base station is the set-up and configuration of certain communication parameters. For example, with packet data mode communications data rate, availability and maximum delay time for each packet communication must be set-up and negotiated between the remote unit and the base. Generally, this negotiation and configuration occurs in real time at the moment when the remote unit first initiates a communication session with the base station. These negotiation and configuration events usually take place in a serialized format, meaning there is an initial sequence of events that occur between an initiating mobile device and a base station, followed by a similar sequence of events between the base station and a target mobile device. These sequence of events entail a process wherein each request or command from one device must first be responded to by the second device before other subsequent requests or commands take place between the devices. Furthermore, all such communication between the first mobile device and the base station must be completed before similar communications occur between the base station and the target mobile device.  
           [0007]    In particular, packet mode capable user equipment request data sessions from their serving infrastructure nodes such as the base station by means of signaling negotiations. Essentially, a signaling channel has to be established and authenticated with the base station system in order for a service to be established between the mobile unit and the base. A certain amount of time delay is associated with the signaling from the initiating mobile unit, the authentication by the system and the negotiation of a certain quality of service. This time delay phenomena is further exaggerated when a first mobile unit attempts to communicate with a second mobile unit or paged target. In such an instance, the paged target or second mobile unit will go through the same set-up and negotiation procedure in order to establish a link with the base station system, thus resulting in a lengthy set-up time.  
           [0008]    A reduction in the set-up time will result in quicker communications and ultimately a reduction in the amount of time for which a particular communication frequency is tied up. The importance of reducing this time can be quite dramatic depending on the mobile unit application. For instance, a dispatch unit that needs to communicate with multiple mobile units would benefit greatly from a reduced set-up time in reaching the targets. As such, there exists a need to provide a system and method to reduce the time and set-up procedures for communication between an initiating mobile unit and other target mobile units.  
         BRIEF SUMMARY OF THE INVENTION  
         [0009]    The invention relates to a system and method for use in wireless packet data mode communications, for enabling communication between a source device and one or more target devices by capturing in a control structure, one or more communication parameters during the set up of the source device and a base station. The set-up involves a series of interactive and sequenced communications between the source device and the base station. The invention involves the transmitting of the control structure to the one or more target devices and utilizing the control structure to contemporaneously configure the one or more target devices so that the target devices can communicate with the source device via the base station. One of the advantages of the invention is the reduction in set-up time for remote units. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a block diagram of an exemplary wireless communication system in which the invention can be practiced.  
         [0011]    [0011]FIG. 2 is an electrical blocked diagram of an exemplary remote unit in accordance with the invention.  
         [0012]    [0012]FIG. 3 is a block diagram of the service level communications on a typical wireless network.  
         [0013]    [0013]FIG. 4A is a flow diagram representing the communications initiated by a remote unit to a base station.  
         [0014]    [0014]FIG. 4B is a flow diagram of the communication initiated by a base to a target remote unit.  
         [0015]    [0015]FIG. 5 is a flow diagram representing the communication from a mobile unit to a base in addition to the creation of a control packet data unit according to the method of the invention.  
         [0016]    [0016]FIG. 6 illustrates an exemplary structure for a control packet data unit.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    The invention provides a unique system and method for setting up and establishing communication between remote units and a base station. The invention is applicable in wireless communication devices that utilize packet data modes for paging or chatting.  
         [0018]    Referring initially to FIG. 1, a blocked diagram illustrates a wireless communication system, environment in which the invention can be practiced. As shown, a fixed portion  108  includes one or more base stations  106 , which provide communication to a plurality of remote user equipment  102 . The base stations  106  coupled by communication link  116  preferably communicates with the user equipment  102  utilizing conventional radio frequency techniques. One or more antennae  104  provide communication from the base stations  106  to the remote user equipment  102 . The base stations  106  preferably also receive RF signals from the plurality of remote user equipment units  102  via antennae  104 . In an embodiment of the invention messages communicated between base station  106  and remote user equipment  102  comprise a selective addressing scheme to identify the initiating or target device. Information exchanged between base station  106  and remote user equipment  102  can include data messages, commands and adjustments to operating parameters for the communication system. Also transmitted between remote user equipment  102  and base stations  106  are responses to scheduled messages, positive acknowledgments (ACKS), negative acknowledgments (NAKS), and unscheduled messages such as registration requests and requests for items of information. It will be appreciated by those skilled in the art that other methods and schemes for wireless communication may be utilized to communicate between the base station  106  and the remote user equipment  102 , or between multiple remote user equipment  102 . Such methods are contemplated by and are within the scope of the invention.  
         [0019]    The fixed portion  108  of the communications network  100  is coupled to a public switch telephone network (PSTN)  110  for receiving and sending messages to other device types like telephone  112  and computer  114 . Calls or information initiated by or destined for a remote user equipment  102  can be received by or originated from a device such as telephone  112  or computer  114 . Those skilled in the art recognize that alternate types of networks, for example, local area networks (LAN), wide area networks (WAN) and the Internet, can be used for receiving or sending selective call information to the wireless network  100 . A computer such as computer  114  can also serve as a central repository for various applications and information utilized by the wireless communication system.  
         [0020]    It will be further appreciated that the invention is applicable to other types of wireless communication systems including dispatch systems, cellular telephone systems and voice and/or data messaging systems. A remote communication unit that can be utilized in the invention will be discussed with reference to FIG. 2.  
         [0021]    [0021]FIG. 2 illustrates an exemplary remote user equipment  102  and its various components. The remote user equipment  102  comprises an antennae  202  that is utilized for receiving inbound messages and for transmitting outbound messages. The antennae  202  is coupled to a transmitter  204  and a receiver  206 . Both the transmitter  204  and the receiver  206  are coupled to a processor  216  for processing information relating to outbound and inbound messages and for controlling the remote user equipment  102  in accordance with the invention. A user interface  210  is operably coupled to the processor  216  for providing user interaction and feedback. In an embodiment of the invention, the user interface  210  comprises a display  212  and a keyboard  214 . The display  212  provides a user with operative information and feedback from the processor  216 . The keyboard  214  enables a user to provide input or response to the processor  216 . Other methods and systems for user interaction and feedback could also be used to accomplish the objects of the invention. A crystal oscillator  208 , provides conventional timing to the processor  216  and other components of the remote user equipment  102 . Processing is performed by the processor  216  in conjunction with memory  218 . The memory  218  comprises software instruction and data for programming and operating the remote user equipment  102  in accordance with the invention. Remote user equipment  102  operates to communicate to a base station  106 . Such operation will be discussed in detail with reference to FIGS. 3, 4A,  4 B and  5 .  
         [0022]    For purposes of illustration, explanation and not limitation, the invention will be discussed with reference to the UMTS environment. The invention is equally applicable and capable to be utilized in any wireless communication strategy or methodology.  
         [0023]    A brief overview of the UMTS environment will be discussed with reference to FIG. 3. As shown in FIG. 3, a base station  106  comprises one or more UMTS Terrestrial Radio Access Network (UTRAN) components  302 . As previously mentioned, UMTS is a packet mode communication scheme. As such, there exists a General Packet Radio Service (GPRS) that provides the environment for communication between remote user equipment  102  and base station  106 . GPRS provides packet routing and gateway services through a Serving GPRS Support Node (SGSN)  304 . SGSN is positioned to communicate between remote user equipment  102  and UTRAN  302  of a base station  106 . SGSN  304  also provides connection and communication to an IP network  306 .  
         [0024]    In operation, a remote user equipment  102  negotiates with SGSN  304  for the quality of service that will be utilized in the communication with UTRAN  302  of the base station  106 . Quality of service includes such things as data rate for communications, availability, maximum time delay for packet communications and so on. The quality of service negotiation involves multiple bidirectional communications between remote user equipment  102  and base station  106  devices. The nature of these device communications and the types of messages that are exchanged will be discussed further with reference to FIGS. 4A and 4B.  
         [0025]    Turning to FIGS. 4A and 4B, the steps for an initiating remote user equipment  102  to communicate via a base station  106  to a paged/receiving second remote user equipment  102  are illustrated. As discussed earlier, a certain amount of negotiation must take place between both the initiating and receiving user equipment  102  and the base station  106 . This negotiation takes time, because not only will the initiating target undergo a negotiation process, the paged target will also undergo the same process, thus doubling the total time required to connect the two remote user equipments  102  to each other. Although this time may not be a problem for a remote computer user dealing with data, in the case of a remote voice user it adds to the total set-up time required for a particular service and produces noticeable delays.  
         [0026]    [0026]FIG. 4A illustrates the message flow between a base system  106  and a source or initiating user equipment  102 . FIG. 4A also illustrates the serialized nature of the message flow from the moment the user equipment  102  initiates a packet data page until a time when the base station  106  has received the first Packet Data Unit (PDU). In general, system information and other relevant data is communicated to remote equipment such as user equipment  102  on an ongoing basis, this is represented as step  402 . In an embodiment of the invention the user equipment  102  includes a Press To Talk (PTT) button, which serves to initiate communications or paging services to the wireless network. The activation of PTT causes a connection request such as shown at step  404 , to be initiated from user equipment  102  to the base station  106 . In response, base station  106  acknowledges such requests with a connection set-up signal at step  406 . This signals the user equipment to begin a set-up process, the completion of which prompts a connection set-up complete signal from user equipment  102 , at step  408 . The completion signal is also simultaneously followed by a service request from user equipment  102  to base station  106  at step  410 . In response, base station  106  performs an authentication and ciphering request at step  412 , to which the user equipment  102  responds at step  414 . Following this, a security mode command is forwarded at step  416  to user equipment  102 . The command results in a response signal to indicate the completion of the security mode, at step  418 . Once security negotiations are complete, a request is initiated by user equipment  102  at step  420  to activate the PDP context on the base station  106 . This is followed by a radio bearer set-up method from the base station  106  to the user equipment  102 , at step  422 . The radio bearer set-up completion is signaled back at step  424 . The receipt of the radio bearer set-up completion causes the base station  106  to accept the activation of the PDP context and a confirmation of the acceptance is sent to the user equipment  102  at step  426 . The conclusion of this mobile originated packet data session that was started by the initiating user equipment  102 , prompts the start of a subsequent packet data session from base station  106  to the target user equipment  102 . In other words, a mobile terminated packet data session is originated by the base station  106  to a target user equipment  102 . The process of this data session will be discussed with reference to FIG. 4B.  
         [0027]    As shown in FIG. 4B, the base station  106  transmits system information to a target mobile user equipment  102  at step  430 . The base station  106  also transmits paging type information at step  432  to the target user equipment  102 . This is then followed by the target user equipment  102  initiating a connection request to the base station at step  434 . From this point on, the steps and the nature to communication between the target user equipment  102  and the base station  106  is identical to that of the initiating user equipment and base station which was previously described with reference to FIG. 4A, in other words, steps  434  through  458  in FIG. 4B are identical to steps  404  through  426  in FIG. 4A i.e. a repetitive process. This repetitive process is alleviated by the system and method of the invention. Information that results from the initial communication between the initiating user equipment  102  and base station  106 , is utilized for subsequent communication from base station  106  to a target user equipment  102 . This process of reusing information will be discussed with reference to FIG. 5.  
         [0028]    [0028]FIG. 5 illustrates a proposed change to the process flow for the initial set-up of user equipment  102   a  and utilizes a control PDU which contains information that is ultimately sent from the base station  106  to a target user equipment  102   b . The set-up process for the initiating user equipment  102   a  is identical in nature and duration to the set-up process that was discussed with reference to FIG. 4A. In other words, steps  502  through  526  are identical to the previously discussed steps  402  through  426 . In an embodiment of the invention execution of steps  502 - 506  take approximately 5.3 seconds. As previously discussed, steps  502  to  526  and steps  402  to  426  provide set-up for the initiating user equipment  102   a  and are communicated to the base station  106 . The base station  106  must then communicate to and set-up a target user equipment  102   b  as discussed with reference to FIG. 4B which take approximately 5.5 seconds i.e. steps  430  through  458 . As such, the cumulative total time for setting up communications between an initiating user equipment  102   a  and a target user equipment  102   b  would be approximately 10.8 seconds. The method of the invention provides a way to significantly reduce the set-up time. This is done by paging a target user equipment  102   b  as soon as the initiating user equipment  102   a  expresses a need to communicate with such target rather than waiting until the set-up of the initiator is complete. This initial communication to the target occurs during the set-up process of the initiating user equipment  102 a. In other words, early in the set-up process of the initiator, the initiator informs the base station of its intent to page a particular target. While the initiator is being set-up, the system locates the target and begins to set the target up for a dispatch session. The method of the invention reduces total set-up time by creating a control PDU during the set-up session of the initiating user equipment  102   a . The details of the content of a control PDU will be discussed with reference to FIG. 6 later on in this document. Returning to FIG. 5, the activation of the PDP context at step  526  initiates the sending of a PDU to the paged target user equipment  102   b  by the base station  106 . The content of the control PDU is utilized by the method and system of the invention to set-up the radio bearer service and other parameters of the target user equipment  102   b . In other words, the need for the prolonged negotiation between base station  106  and the target user equipment  102   b  is eliminated, thus reducing set-up time.  
         [0029]    In order to facilitate this information exchange using the control PDU, a certain structure which is known to both sides of the communication is required.  
         [0030]    An exemplary PDU structure is shown and discussed with reference to FIG. 6 and generally referenced as  600 . While this illustrated PDU control structure  600  contains certain specific parameters, it will be understood by those skilled in the art that other structures, formats and parameters could be utilized to achieve the same results. In an embodiment of the invention, the control PDU structure  600  contains a PDU operation code  602 , a PDU length  604 , a service intent parameter  606  and a target IP  608 . A PDU with this structure is built and sent early in the configuration process of an initiating user equipment to inform a target device of the intent of the initiator to make contact with that target device. The PDU operation code  602  identifies the step in the set-up process, the PDU length  604  identifies the total length of the PDU control structure, the service intent parameter  606  then contains the information that is associated with a particular operation code and the target IP uniquely identifies the target user equipment  102   b.    
         [0031]    As would be understood by those skilled in the art, functions discussed as being performed on the user equipment  102   a ,  102   b  or the base station  106  could be performed on any one or more of those systems, in a variety of combinations and configurations, and such variations are contemplated and within the scope of the invention.  
         [0032]    The invention has been described in relation to particular embodiments which are intended in all respects to be illustrative rather than restrictive. Alternative embodiments will become apparent to those skilled in the art to which the invention pertains without departing from its scope.  
         [0033]    From the foregoing, it will be seen that this invention is one well adapted to obtain all of the ends and objects set forth above, together with other advantages which are obvious and inherent to the system and method. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims.