PATENT DOCUMENT

Publication Number: US-8504013-B2
Application Number: US-98701711-A
Country: US
Kind Code: B2

Title: Radio resource management in a mobile device

Abstract:
Managing radio resources between a mobile device and a wireless network includes at least the following. An application processor in the mobile device classifies radio resources available into at least two distinct sets, a first set of active connections and a second set of potential connections. The application processor forms a measurement message that includes information about the measured radio resources and communicates the measurement message to a wireless network through a transceiver. Before receiving an acknowledgement of the measurement message from a radio network subsystem in the wireless network, the application processor determines at least one parameter included in the measurement message requires updating. The transceiver stops transmitting the measurement message in response to commands from the application processor.

Claims:
What is claimed is: 
     
       1. A method, comprising:
 at a mobile wireless device, 
 classifying a plurality of radio resources available to the mobile wireless device into at least two distinct sets, a first set of radio resources used for active connections and a second set of radio resources used for potential connections; 
 measuring a signal quality of at least one radio resource in the plurality of radio resources; 
 transmitting a portion of a first measurement message to a base transceiver station in a wireless network, the first measurement message including information about the at least one measured radio resource; 
 before receiving an acknowledgement to the transmitted portion of the first measurement message from the base transceiver station, detecting a change to the signal quality of the at least one measured radio resource; 
 stopping transmission of the portion of the first measurement message; and 
 transmitting a portion of a second measurement message to the base transceiver station in the wireless network, the second measurement message including updated information about the at least one measured radio resource. 
 
     
     
       2. The method as recited in  claim 1 , wherein the first measurement message includes a transfer request for one of the radio resources in the plurality of radio resources between two of the distinct classification sets. 
     
     
       3. The method as recited in  claim 2 , wherein the first measurement message requests to promote one of the radio resources from the second set of potential connections to the first set of active connections. 
     
     
       4. The method as recited in  claim 2 , wherein the first measurement message requests to demote one of the radio resources from the first set of active connections to the second set of potential connections. 
     
     
       5. The method as recited in  claim 3 , further comprising:
 transferring the one of the radio resources from a third set of unused connections to the second set of potential connections before transmitting the portion of the first measurement message. 
 
     
     
       6. The method as recited in  claim 1 , wherein the first measurement message is a pilot strength measurement message (PSSM). 
     
     
       7. A mobile wireless device, comprising:
 an application processor coupled to a wireless transceiver, the application processor arranged to execute instructions for:
 classifying a plurality of radio resources available to the mobile wireless device into at least two distinct sets, a first set of radio resources used for active connections and a second set of radio resources used for potential connections; 
 forming a measurement message, the measurement message including information about at least one radio resource in the plurality of radio resources measured by the wireless transceiver; 
 transferring the measurement message to the wireless transceiver; 
 determining at least one parameter included in the measurement message requires updating before receiving an acknowledgement of the measurement message from a radio network subsystem in a wireless network; 
 commanding the wireless transceiver to stop transmission of the measurement message; and 
 
 the wireless transceiver arranged to
 transmit at least a portion of the measurement message to the radio network subsystem in the wireless network; and 
 stopping transmission of the measurement message in response to one or more commands received from the application processor. 
 
 
     
     
       8. The mobile wireless device as recited in  claim 7 , wherein the measurement message includes a transfer request for one of the radio resources in the plurality of radio resources between two of the distinct classification sets. 
     
     
       9. The mobile wireless device as recited in  claim 7 , wherein the measurement message includes a radio frequency signal parameter measured by the transceiver in the mobile wireless device. 
     
     
       10. The mobile wireless device as recited in  claim 7 , wherein the measurement message is a layer 3 service data unit transmitted by the transceiver using one or more layer 2 protocol data units. 
     
     
       11. The mobile wireless device as recited in  claim 10 , wherein each layer 2 protocol data unit requires acknowledgement from the wireless network. 
     
     
       12. The mobile wireless device as recited in  claim 11 , wherein the application processor is further arranged to execute instructions for:
 forming a reset message that indicates a reset of layer 2 protocol data unit sequence numbering used by the mobile wireless device to the wireless network; 
 transferring the reset message to the transceiver; and 
 
       the transceiver is further arranged to:
 receive the reset message; and 
 transmit the reset message to radio network subsystem in the wireless network. 
 
     
     
       13. The mobile wireless device as recited in  claim 9 , wherein the measurement message includes a pilot strength measurement message (PSSM). 
     
     
       14. Non-transitory computer program product encoded in a non-transitory computer readable medium for controlling a mobile wireless device connected to a radio network system in a wireless network, the non-transitory computer program product comprising:
 in the mobile wireless device, 
 non-transitory computer program code for classifying a plurality of radio resources available to the mobile wireless device into at least two distinct sets, a first set of radio resources used for active connections and a second set of radio resources used for potential connections; 
 non-transitory computer program code for measuring a signal quality of at least one radio resource in the plurality of radio resources; 
 non-transitory computer program code for transmitting a portion of a first measurement message to the radio network system in the wireless network, the first measurement message including information about the measured at least one radio resource in the plurality of radio resources; 
 non-transitory computer program code for storing the portion of the first measurement message pending receipt of an acknowledgement of the portion of the first measurement message from the radio network system; 
 non-transitory computer program code for determining when at least some of the information included in the first measurement message is out of date; 
 non-transitory computer program code for stopping transmission of any pending portions of the first measurement message; 
 non-transitory computer program code for deleting the stored first measurement message when the first measurement message is out of date and no acknowledgement of the measurement message is received. 
 
     
     
       15. The non-transitory computer program product as recited in  claim 14 , further comprising:
 non-transitory computer program code for transmitting a portion of a second measurement message to the radio network system in the wireless network, the second measurement message including updated information about the measured at least one radio resource in the plurality of radio resources. 
 
     
     
       16. The non-transitory computer program product as recited in  claim 14 , wherein the information included in the first and second measurement messages includes measurements of at least one radio frequency parameter for one or more connections between the mobile wireless device and the wireless network. 
     
     
       17. The non-transitory computer program product as recited in  claim 14 , wherein the first and second measurement messages are layer 3 protocol data units. 
     
     
       18. The non-transitory computer program product as recited in  claim 17 , further comprising:
 non-transitory computer program code for transmitting one or more layer 2 protocol data units derived from the layer 3 protocol data units; 
 non-transitory computer program code for re-transmitting the one or more layer 2 protocol data units when no acknowledgement is received within a pre-determined time interval; and 
 non-transitory computer program code for resetting layer 2 sequence numbers used for transmitting layer 2 protocol data units after deleting the stored first measurement message. 
 
     
     
       19. The non-transitory computer program product as recited in  claim 15 , wherein the updated information includes measurements of the at least one radio resource that exceed a pre-determined threshold. 
     
     
       20. A method for managing radio resources between a mobile wireless device and a wireless network, the method comprising:
 at the mobile wireless device, 
 measuring radio frequency parameters of signals received by the mobile wireless device from one or more radio network subsystems in the wireless network; 
 classifying the measured radio frequency signals into at least two distinct sets, a first set used for active connections and a second set used for potential connections; 
 requesting a promotion of at least one of the radio frequency signals from the second potential set to the first active set by transmitting a measurement message to the wireless network; 
 before receiving a confirmation of the requested promotion from the wireless network, measuring a change in the received signal quality from at least one of the one or more radio network subsystems that exceeds a pre-determined threshold; and 
 cancelling the requested promotion. 
 
     
     
       21. The method as recited in  claim 20 , wherein the promotion request is included in a first measurement message and the cancellation is included in a second measurement message transmitted by the mobile wireless device to the wireless network.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application is related to co-pending U.S. patent application Ser. No. 12/987,012 entitled “CONTROL OF MEASUREMENT MESSAGING IN A MOBILE DEVICE” by Prashant H. Vashi et al., filed concurrently herewith. 
     TECHNICAL FIELD 
     The described embodiments relate generally to wireless mobile communications. More particularly, a method is described for managing radio resources used for communication between a mobile wireless communication device and a wireless communication network. 
     BACKGROUND OF THE INVENTION 
     Mobile wireless communication devices, such as a cellular telephone or a wireless personal digital assistant, can provide a wide variety of communication services including, for example, voice communication, text messaging, internet browsing, and electronic mail. Mobile wireless communication devices can operate in a wireless communication network of overlapping “cells”, each cell providing a geographic area of wireless signal coverage that extends from a radio network subsystem located in the cell. The radio network subsystem can include a base transceiver station (BTS) in a Global System for Communications (GSM) network or a Node B in a Universal Mobile Telecommunications System (UMTS) network. The radio network subsystem can also be referred to as a radio access network in a Code Division Multiple Access (CDMA) network and can include a BTS. 
     The mobile wireless communication device can receive signals transmitted from one or more cells in the wireless communication network. The radio network subsystems in each of the cells can be located at different distances from the mobile wireless communication device, and therefore signals received at the mobile wireless communication device can vary in signal strength and/or signal quality. The mobile wireless communication device can measure and monitor the received signals to determine to which cells a connection can be achieved and maintained. Together with one or more radio network subsystems in the wireless communication network, the mobile wireless communication device can select to which cells to connect and disconnect as the mobile wireless communication device moves throughout the wireless network. 
     Base transceiver stations from which the mobile wireless communication device can receive and measure signals can be classified by the mobile wireless communication device into several different categories and grouped into sets. The mobile wireless communication device can report measurements received and request changes to classification of base transceiver stations or equivalently unique signals that identify the base transceiver stations, such as pilot signals received from base transceiver stations. Changes in classification of pilot signals can require communication with the wireless network through messages exchanged with the radio network subsystem including the base transceiver stations. Message exchange can require repeated transmissions in a noisy environment, and acknowledged transmission of a message can take significant time. In a dynamically varying radio frequency environment, messages undergoing retransmission can become out of date, resulting in unnecessary transmissions and delayed updates to the classification. 
     Thus there exists a need to manage radio resources more effectively between a mobile wireless communication device and a wireless communication network during dynamically changing network conditions. 
     SUMMARY OF THE DESCRIBED EMBODIMENTS 
     The described embodiments relate generally to wireless mobile communications. More particularly, a method and apparatus is described for managing radio resources between a mobile wireless communication device and a wireless communication network. 
     In one embodiment, a method to manage radio resources is performed at a mobile wireless communication device when the mobile wireless device is connected to a radio network subsystem in a wireless network. The method includes at least the following steps. The mobile wireless device classifies two or more radio resources available to the mobile wireless device into at least two distinct sets. A first set of radio resources is used for active connections, and a second set of radio resources is used for potential connections. The mobile wireless device measures a signal quality of at least one radio resource in the two or more radio resources classified into the sets. The mobile wireless device transmits a portion of a first measurement message to the base transceiver station in the wireless network. The first measurement message includes information about the measured radio resource. The mobile wireless device awaits an acknowledgement of the transmitted first measurement message. Before receiving the acknowledgement from the base transceiver station, the mobile wireless device detects a change to the signal quality of at least one of the measured radio resources. The mobile wireless device stops transmitting the portion of the first measurement message and transmits a portion of a second measurement message to the base transceiver station in the wireless network. The second measurement message includes updated information about the measured radio resource. 
     In a further embodiment, a mobile wireless communication device including a wireless transceiver to transmit and receive signals from a radio network subsystem in a wireless network and an application processor coupled to the wireless transceiver is described. The application processor is arranged to execute the following instructions. The application processor classifies two or more radio resources available to the mobile wireless device into at least two distinct sets, a first set of radio resources used for active connections and a second set of radio resources used for potential connections. The application processor forms a measurement message that includes information about at least one radio resource measured by the wireless transceiver. The application processor transfers the measurement message to the wireless transceiver. The application processor determines at least one parameter included in the measurement message requires updating before receiving an acknowledgement of the measurement message from the radio network subsystem in the wireless network. The application processor commands the wireless transceiver to stop transmitting the measurement message. The wireless transceiver is arranged to transmit at least a portion of the measurement message to the radio network subsystem in the wireless network. The wireless transceiver is also arranged to stop transmission of the measurement message in response to one or more commands received from the application processor. 
     In another embodiment, a non-transitory computer program product encoded in a non-transitory computer readable medium for controlling a mobile wireless device connected to a radio network subsystem in a wireless network is described The non-transitory computer program product includes non-transitory computer program code for classifying two or more radio resources available to the mobile wireless device into at least two distinct sets. The two distinct sets includes at least a first set of radio resources used for active connections and a second set of radio resources used for potential connections. The non-transitory computer program product also includes non-transitory computer program code for measuring a signal quality of at least one radio resource in the two or more classified radio resources. The non-transitory computer program product further includes non-transitory computer program code for transmitting a portion of a first measurement message to the radio network system in the wireless network. The first measurement message includes information about the measured at least one radio resource in the two or more radio resources. The non-transitory computer program product yet further includes non-transitory computer program code for storing the portion of the first measurement message pending receipt of an acknowledgement of the portion of the first measurement message from the radio network system. The non-transitory computer program product also includes non-transitory computer program code for determining when at least some of the information included in the first measurement message is out of date. The non-transitory computer program product includes non-transitory computer program code for stopping transmission of any pending portions of the first measurement message. The non-transitory computer program product includes non-transitory computer program code for deleting the stored first measurement message when the first measurement message is out of date and no acknowledgement of the first measurement message is received. 
     In a further embodiment, a method for managing radio resources between a mobile wireless device and a wireless network is described. The method includes, at the mobile wireless device, at least the following steps. The mobile wireless device measures radio frequency parameters of signals received by the mobile wireless device from one or more radio network subsystems in the wireless network. The mobile wireless device classifies the measured radio frequency signals into at least two distinct sets, a first set used for active connections and a second set used for potential connections. The mobile wireless device requests a promotion of at least one of the radio frequency signals from the second potential set to the first active set by transmitting a measurement message to the wireless network. The mobile wireless device measures a change in the received signal quality from at least one of the one or more radio network subsystems that exceeds a pre-determined threshold before receiving a confirmation of the requested promotion from the wireless network. The mobile wireless device cancels the requested promotion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention and the advantages thereof may best be understood by reference to the following description taken in conjunction with the accompanying drawings. 
         FIG. 1  illustrates a mobile wireless communication device located within a wireless cellular communication network. 
         FIG. 2  illustrates a hierarchical architecture for a wireless communication network. 
         FIG. 3  illustrates a communication protocol stack for a mobile wireless communication device used in the wireless communication network of  FIG. 2 . 
         FIG. 4  illustrates a multiple radio access bearer wireless connection including circuit and packet switching. 
         FIG. 5  illustrates a second hierarchical architecture for a wireless communication network. 
         FIG. 6  illustrates a communication protocol stack for a mobile wireless communication device used in the wireless communication network of  FIG. 5 . 
         FIG. 7  illustrates a mobile wireless communication device. 
         FIG. 8  illustrates communication from the mobile wireless communication device to a remote device. 
         FIG. 9  illustrates packet communication with acknowledgements. 
         FIG. 10  illustrates pilot set maintenance in the mobile wireless communication device. 
         FIG. 11  illustrates pilot movement among pilot sets based on changing signal quality. 
         FIG. 12  illustrates a method for measurement message control in a mobile wireless communication device. 
         FIG. 13  illustrates a second method for measurement message control in a mobile wireless communication device. 
         FIG. 14  illustrates a method for radio resource management in a mobile wireless communication device. 
         FIG. 15  illustrates a second method for radio resource management in a mobile wireless communication device. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     In the following description, numerous specific details are set forth to provide a thorough understanding of the concepts underlying the described embodiments. It will be apparent, however, to one skilled in the art that the described embodiments may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the underlying concepts. 
       FIG. 1  illustrates a wireless communication network  100  of overlapping wireless communication cells to which a mobile wireless communication device  106  can connect. Each wireless communication cell can cover a geographic area extending from a centralized radio network subsystem. The mobile wireless communication device  106  can receive communication signals from a number of different cells in the wireless communication network  100 , and each cell can be located at a different distance from the mobile wireless communication device  106 . In a second generation (2G) wireless communication network, e.g. a network following a Global System for Mobile Communications (GSM) protocol, the mobile wireless communication device  106  can connect to a radio network subsystem in the wireless communication network  100  using one radio link at a time serially. For example, the mobile wireless communication device  106  can be connected initially to a radio network subsystem (RNS)  104  in a serving cell  102 . The mobile wireless communication device  106  can monitor signals from radio network subsystems in neighbor cells. The mobile wireless communication device  106  can transfer its connection from the radio network subsystem  104  in the serving cell  102  to a radio network system  108  in a neighbor cell  110  as the mobile wireless communication device moves within the wireless communication network  100 . The mobile wireless communication device  106  can monitor signals from nearby cells and can keep track of signal quality received at the mobile wireless communication device  106  from each of the cells. Information about received signal quality can be communicated by the mobile wireless communication device  106  to the wireless communication network  100  using measurement messages (or more generally management messages or control messages). The wireless communication network  100  can use the information provided in the measurement messages to determine if and when to change the cell to which the mobile wireless communication device  106  can be connected. 
     In a third generation (3G) wireless communication network, such as a network based on a Universal Mobile Telecommunication System (UMTS) protocol, the mobile wireless communication device  106  can be connected to one or more radio network subsystems simultaneously through multiple radio access bearers. Each of the radio access bearers can transport a different communication service independently, such as a voice service on a first radio access bearer and a data service on a second radio access bearer. The mobile wireless communication device  106  can also be connected by multiple radio access bearers simultaneously to the radio network subsystem (RNS  104 ) in the serving cell  102  (if the RNS  104  supports such a simultaneous multiple radio link connection). The mobile wireless communication device  106  can also be connected by a first radio access bearer to the RNS  104  in the serving cell  102  and to a second RNS  108  in the neighbor cell  110  simultaneously. Advanced mobile wireless communication devices  106 , sometimes referred to as “smart” phones, can provide a diverse array of services to the user using a connection with multiple radio access bearers. 
     In a code division multiple access (CDMA) network, the mobile wireless communication device  106  can also be connected through multiple radio links to the wireless communication network  100 , particularly during a procedure known as soft handoff (or soft handover). Continuous access to communication services while the mobile wireless communication device  106  traverses the wireless communication network can require a seamless handoff between different radio network subsystems located in different cells. The mobile wireless communication device  106  can transmit measurement messages to the wireless communication network  100  that can contain measures of signal quality received by the mobile wireless communication device  106  from the one or more different radio network subsystems. Representative measures of signal quality can include received signal code power (RSCP) and an energy per chip to total noise/interference ratio (E c I o ). While the mobile wireless communication device  106  is connected to a base transceiver station in a first cell by a first radio frequency connection, the wireless communication network  100  can add a second radio frequency connection between the mobile wireless communication device  106  and a base transceiver station in a second cell to provide a “soft handoff” before terminating the first radio frequency connection. The mobile wireless communication device  106  can thus be connected to the first base transceiver station in the first cell, then to two base transceiver stations located in two different cells simultaneously, and then to the second base transceiver station in the second cell. A successful soft handoff can maintain a communication link between the mobile wireless communication device  106  and the wireless communication network  100  when the first radio frequency connection deteriorates in signal quality while the second radio frequency connection improves in signal quality. 
     The mobile wireless communication device  106  can be connected to two or more cells simultaneously, and radio frequency signals from each of the cells to which the mobile wireless communication device  106  is connected can be used together to improve call performance. Communication of measurement information gathered at the mobile wireless communication device  106  and provided from the mobile wireless communication device  106  to the wireless communication network  100  can provide critical information for determining to which cells to connect or disconnect, thereby providing improved call stability. As the measurement messages transmitted by the mobile wireless communication device  106  to the wireless communication network  100  can contain critical information, a wireless communication protocol can be used by the mobile wireless communication device  106  that can require that the measurement messages be acknowledged by the wireless communication network  100  to ensure correct reception. When no acknowledgement has been received by the mobile wireless communication device  106  from the wireless communication network during a pre-determined time interval, the mobile wireless communication device  106  can re-transmit the message that has not been acknowledged. This retransmission can be repeated a pre-determined number of times. After a pre-determined number of successive re-transmissions that do not receive acknowledgement from the wireless communication network  100 , the mobile wireless communication device  106  can determine that at least one of the radio frequency connections to the wireless communication network  100  is “defective.” One or more of the radio frequency connections between the mobile wireless communication device  106  and the wireless communication network  100  can then be terminated. Typically all of the radio frequency connections can be terminated resulting in a “dropped” call, as perceived by the user of the mobile wireless communication device  106 . 
       FIG. 2  illustrates a 3G UMTS wireless communication network  200  including UMTS access network elements. The mobile wireless communication device  106  operating in the UMTS wireless communication network  200  can be referred to as user equipment (UE)  202 . (Wireless mobile communication devices  106  can include the capability of connecting to different wireless communication networks that use different wireless radio access network technologies, such as to a GSM network and to a UMTS network; thus the description that follows can also apply to such “multi-network” devices as well.) In a UMTS wireless network, the UE  202  can connect to one or more radio network subsystems (RNS)  204 / 214  through one or more radio links  220 / 222 . The first RNS  204  can include a radio access system, known as a “Node B”  206 , which transmits and receives radio frequency signals. The Node B  206  can connect with a radio network controller (RNC)  208  in the radio network subsystem  204  that manages communication between the Node B  206  and the core network  236 . Similarly the second RNS  214  can include Node B  210  and RNC  212  that also connect to the core network  236 . Unlike a mobile wireless communication device  106  in a 2G GSM network, the UE  202  in the UMTS network can connect to more than one RNS simultaneously. Each RNS can provide a separate connection for a different service to the UE  202 , such as for a voice connection through a circuit switched voice network and for a data connection through a packet switched data network. Each radio link  220 / 222  can also include one or more radio access bearers that transport signals between the UE  202  and the respective RNS  204 / 214 . Multiple radio access bearers can be used for separate services on separate connections or for supplementing a service with additional radio resources for a given connection. 
     The core network  236  can include both a circuit switched domain  238  that can carry voice traffic to and from an external public switched telephone network (PSTN)  232  and a packet switched domain  240  that can carry data traffic to and from an external public data network (PDN)  234 . Voice and data traffic can be routed and transported independently by each domain. Each RNS can combine and deliver both voice and data traffic to mobile wireless communication devices  106 . The circuit switched domain  238  can include multiple mobile switching centers (MSC)  228  that connect a mobile subscriber to other mobile subscribers or to subscribers on other networks through gateway MSCs (GMSC)  230 . The packet switched domain  240  can include multiple support nodes, referred to as serving GPRS support nodes (SGSN)  224 , that route data traffic among mobile subscribers and to other data sources and sinks in the PDN  234  through one or more gateway GPRS support nodes (GGSN)  226 . The circuit switched domain  238  and the packet switched domain  240  of the core network  236  can each operate in parallel, and both domains can connect to different radio access networks simultaneously. 
     The UMTS wireless communication network  200  illustrated in  FIG. 2  can support several different configurations in which the UE  202  connects through multiple radio access bearers to the wireless communication network. In a first configuration, a “soft” handoff of the UE  202  can occur between the first RNS  204  and the second RNS  214  as the UE  202  changes location within the UMTS wireless communication network  200 . A first radio access bearer through the first RNS  204  can be supplemented by a second radio access bearer through the second RNS  214  before deactivating the first radio access bearer. In this case, multiple radio access bearers can be used for enhancing a connection&#39;s reliability, and the UE  202  can typically be using one service through the multiple radio access bearers. In a second configuration, the UE  202  can connect through the first RNS  204  to the packet switched domain  240  to support a packet data connection and simultaneously connect through the second RNS  214  to the circuit switched domain  238  to support a voice connection. In this case, the UE  202  can maintain a different radio access bearer for each service. In a third configuration, a single RNS can support multiple radio access bearers to the same UE  202 , each radio access bearer supporting a different service. For the second and third configurations, it can be preferred that the establishment and release of each radio access bearer be independent as they can be associated with different services simultaneously. 
       FIG. 3  illustrates a layered protocol stack  300  with which a UE  202  can establish and release connections with the UMTS wireless communication network  200  through an exchange of messages. Higher layers  310  in the layered protocol stack  300 , such as a session management layer, can request a connection of the UE  202  to the wireless communication network  200 . The connection request from the session management layer can result in a series of discrete packetized messages known as radio resource control (RRC) service data units (SDU) passed from an RRC processing block  308  in layer 3 of the protocol stack  300  to a radio link control (RLC) processing block  306  in layer 2 of the protocol stack  300 . A layer 3 SDU can represent a basic unit of communication between layer 3 peers at each end of the communication link. Each layer 3 RRC SDU can be segmented by the RLC processing block  306  into a numbered sequence of layer 2 RLC protocol data units (PDU) for transmission over a communication link. A layer 2 RLC PDU can represent a basic unit of data transfer between layer 2 peers at each end of the communication link. Layer 2 RLC PDUs can be transmitted through additional lower layers in the layer protocol stack  300 , namely a media access control (MAC) layer  304  that maps logical channels  314  into transport channels  312  and a physical layer  302  that provides a radio link “air” interface. At the receiving end of the communication link (not shown), the layer 2 RLC PDUs can be reassembled by another RLC processing block to form a complete layer 3 SDU to deliver to a complementary RRC processing block in a remote device (or other termination). 
     The layer 2 RLC protocol can be configured to operate in an acknowledged mode to provide reliable transport of the layer 2 PDUs over a noisy transmission channel, such as a wireless radio link “air” interface between the mobile wireless communication device  106  and the wireless communication network  100 . If a layer 2 PDU is lost during transmission or incorrectly received by the receiving end (for example the radio network subsystem to which the wireless mobile communication device  106  is connected), the layer 2 PDU can be retransmitted by the transmitting layer 2 RLC processing block  306  before the complementary receiving processing blocks reassemble the complete layer 3 SDU. Error checking and retransmission of the layer 2 PDUs can improve the probability of a correctly received and reassembled layer 3 SDU. 
     The layer 2 RLC protocol can use an automatic repeat request (ARQ) function to trigger retransmissions. The transmitting layer 2 RLC processing block  306  can receive a status report from the receiving layer 2 RLC processing block. The status report can be sent in response to a poll from the transmitting end or can be automatically sent by the receiving end. Polling of the receiving end can be accomplished by setting a polling bit in a field of a transmitted layer 2 PDU. For example, when a polling bit can be set in a layer 2 PDU having the last sequence number for a particular layer 3 SDU. The layer 2 processing block at the receiving end can recognize the polling bit and respond to the poll by indicating the highest sequence number layer 2 PDU in the layer 3 SDU for which all layer 2 PDUs equal to or earlier than the highest sequence number have been correctly received. Alternatively, the receiving end can automatically send a status report when a layer 2 PDU is received out of sequence or incorrectly received, thus alerting the transmitting end that a layer 2 PDU has been lost or corrupted during transmission. The transmitting end can respond to the status report by retransmitting any missing layer PDUs. A segmentation and reassembly function with error checking in the RLC layer 2 processing block  306  can ensure that layer 3 RRC SDUs are transmitted and received completely and correctly. 
     As illustrated in  FIGS. 2 and 4 , a UMTS network can include two distinct domains, a circuit switched domain  238  to carry circuit switched traffic (such as voice or transparent data) and a packet switched domain  240  to transport packet data (such as internet connectivity or voice over IP). As shown in  FIG. 4 , the UE  202  can be simultaneously connected to the circuit switched domain  238  by a radio access bearer  402  to carry voice traffic and to the packet switched domain  240  through a radio access bearer  404  to carry data traffic. A radio access bearer can be considered a channel to transport a circuit switched data stream or a packet switched data stream between the UE  202  and the core network  236  through the RNS  204 . The core network  236  can set characteristics of each radio access bearer including data rate and quality of service based on requirements for the data stream transported and on a user&#39;s subscription among other criteria. A packet data protocol (PDP) context  406  can provide a packet data connection between the UE  202  and the gateway GPRS support node (GGSN)  226  to support the exchange of internet protocol (IP) packets using the radio access bearer  404  over the wireless access network portion of the connection. The PDP context  406  can include a PDP address, such as an IP address, for the UE  202 . The PDP context  406  can be activated by the UE  202  at the session management layer  310 , and the radio access bearer  404  can be established and associated with the PDP context  406  to transport data for the UE  202 . Once established, data can be sent as a series of layer 3 SDUs, each layer 3 SDU transported through numbered sequences of layer 2 PDUs as described above for  FIG. 3 . 
       FIG. 5  illustrates a hierarchical network architecture  500  for a CDMA network similar to the hierarchical network architecture shown in  FIG. 2  for a UMTS network. A mobile station (MS)  502  can be connected to one or more radio access networks (RAN)  504 / 514  through radio links  520 / 522 . The radio links  520 / 522  connect the mobile station  502  to the wireless communication network  100  through baseband transceiver stations (BTS)  506 / 510  located in respective RAN  504 / 514 . The BTS  506 / 510  can be controlled by base station controllers (BSC)  508 / 512 . The RAN  504 / 514  can be connected to a mobile switching center (MSC)  528  located in a circuit switched domain  538  that can handle circuit switched traffic, such as voice calls, to interconnect the MS  502  to the public switched telephone network (PSTN)  532 . The RAN  504 / 514  can also be connected to a packet data serving node (PDSN)  524  located in a packet switched domain  540  that can handle packet switched traffic, such as data connections, to interconnect the MS  502  to a public data network (PDN)  534 . 
     As described above for the UE  202 , the MS  502  can be connected simultaneously to more than one RAN  504 / 514  to provide improved performance and seamless handoff between cells. The MS  502  can monitor radio frequency signals received from the BTS  506 / 510  to which the MS  502  can be connected as well as from additional BTS located in other cells to which the MS  502  can also connect. Based on measurements of radio frequency signals received from the BTS, the MS  502  can transmit messages that contain measurement information to the wireless communication network  100  and can receive control messages from the wireless communication network  100  that can add or delete connections to one or more of the BTS monitored. 
       FIG. 6  illustrates a layered protocol stack  600  for the CDMA MS  502  comparable to the layered protocol stack  300  shown in  FIG. 3  for the UMTS UE  202 . A set of higher layers  608  can include separate processing blocks and communication paths for signaling  616  and for voice/data  618 . Communication between a layer 3 signaling layer to a layer 2 link access control (LAC)  606  layer can use discrete signaling messages or packets that will be referred to as layer 3 SDUs just as described above. The layer 2 LAC  606  can divide the layer 3 SDU into multiple layer 2 PDUs that can be transported over logical channels  614  to the layer 2 media access control (MAC)  604  processing layer. The MAC  604  layer can multiplex the layer 2 PDUs onto transport channels  612 , and the layer 1 physical layer (PHY)  602  can format the PDUs into radio frequency transmissions to transmit to the BTS  506 / 510  in the RAN  504 / 514  in the wireless communication network  100 . The reverse processing can then occur at the destination remote device which can decode the received radio frequency transmissions into a series of layer 2 PDUs that can be re-assembled into a layer 3 SDU. Layer 2 PDUs received correctly can be acknowledged, while incorrectly received (or lost or uncorrectable) layer 2 PDUs can be not acknowledged. Note that Layer 2 PDUs can be checked at the RAN  504 / 514  in the access portion of the wireless network  500 . The RAN  504 / 514  can acknowledge correctly received Layer 2 PDUs. The MS  502  can wait for acknowledgement of the Layer 2 PDU by the RAN  504 / 514  before determining that the Layer 2 PDU was received correctly. The layer 2 processing blocks in the MS  502  can retransmit the Layer 2 PDU when no acknowledgement is received. 
     As the MS  502  can periodically monitor received signals, including their signal quality, updated layer 3 messages can be formed and transmitted that can indicate updated signal quality values (or other measurements or calculations made periodically by the MS  502 ). As the radio frequency environment for the MS  502  can change rapidly as the MS  502  moves within the wireless communication network  500 , a more recently formed layer 3 message can contain updated measurements that can supersede an previously formed and transmitted layer 3 message. The older transmitted layer 3 message and particularly one or more of the constituent layer 2 PDUs that can be used to transport the layer 3 message, can be pending acknowledgement of correct reception. 
     When transmission of the older layer 3 message is not complete, including receipt of acknowledgement for each of the layer 3 message&#39;s constituent layer 2 PDUs, the older layer 3 message can be “outdated” and no longer correctly describe the received signal conditions at the transmitting MS  502 . In current implementations, the layer 3 processing blocks can be unaware of the incomplete reception of the layer 3 message. Instead the layer 3 signaling block  616  can transmit a new layer 3 message independent of the previously transmitted layer 3 message. The lower layer processing blocks in the MS  502  can continue to retransmit the layer 2 PDUs for the earlier outdated layer 3 message unnecessarily, which can waste scarce radio frequency bandwidth. In addition, unsuccessful reception of one or more of the layer 2 PDUs, which can include repeat retransmission failures, can ultimately lead to a termination of the radio frequency connection between the MS  502  and the wireless communication network  500 . As will be described below, the layer 3 processing block can instruct the layer 2 processing blocks to purge older “outdated” layer 3 messages and cease transmitting their constituent layer 2 PDUs, rather than continue to send pending layer 3 messages and their constituent layer 2 PDUs that can no longer contain accurate measurement information. The layer 3 processing block can also send a reset message that can indicate to the wireless communication network  100  a reset of layer 2 sequence numbers associated with the layer 2 PDUs transmitted by the mobile wireless communication device  106 . 
       FIG. 7  illustrates processing elements  700  of a mobile wireless communication device  106  including an application processor (AP)  702  and a transceiver (XCVR)  704 . The AP  702  can perform higher layer functions, such as requesting connections and monitoring the performance of radio frequency links. The AP  702  can form messages that contain measurement information gathered from signals received by the mobile wireless communication device  106  through the XCVR  704 . In some embodiments, the layer 3 processing blocks, such as the signaling block  616  shown in  FIG. 6  and the radio resource control  308  block shown in  FIG. 3 , can be executed by the AP  702 . The layer 2 processing blocks, including the link access control  606  and media access control  604  blocks shown in  FIG. 6 , as well as the radio link control  306  and media access control  304  blocks shown in  FIG. 3 , can be executed by the XCVR  704 . In some embodiments, the layer 2 and layer 3 processing blocks can be contained in the same processing unit, and thus the division between the AP  702  and the XCVR  704  can also be achieved by different processing blocks operating within a more general purpose common computing unit. 
       FIG. 8  illustrates communication between processing elements in the mobile wireless communication device  106  and a remote device  814  through a wireless access radio link  808 . The application processor  702  can generate data units  804 , such as voice or data packets for a connection between the mobile wireless communication device  106  and the remote device  814 . The data units  804  can also include signaling messages that can provide the wireless communication network  100  to which the mobile wireless communication device  106  can be connected information regarding the state of the mobile wireless communication device  106  and of the wireless access radio link  808 . The data units  804  can be transferred to the transceiver  704  and be transformed to appropriately sized and formatted signals for transmission over the wireless access radio link  808  to the radio access network  810 . The transformation of data units  804  into wireless transmissions can include dividing layer 3 SDUs into one or more layer 2 PDUs as described above. The application processor  702  can also send commands  802  to the transceiver  704 , which can also include instructions to the transceiver  704  to indicate how data units  804  can be handled. 
     As described above, some data units  804 , such as certain measurement messages can require acknowledgement from a destination point, such as the remote device  814  or from the radio access network  810 , to ensure correct reception. Until acknowledgement is received, the transceiver  704  can repeatedly transmit a data unit  804  up to a maximum number of times set by a pre-determined counter value. In systems using a CDMA2000 communication protocol, an N1m counter value can be established that can indicate the maximum number of transmissions for a layer 2 PDU that requires acknowledgement. An acknowledgement of the transmitted data unit  804  can be received from the remote device  814  through a remote feedback path  806  or from the radio access network  810  through a local feedback path  816 . Until the acknowledgement is received by the mobile wireless communication device  106 , the application processor  702  and the transceiver  704  in the mobile wireless communication device  106  can consider the transmitted data unit  804  to be in transit but to not be confirmed to be received correctly by the remote device  814  or by the radio access network  810 . In a CDMA2000 system, the N1m counter value can be applied to all L2 PDUs that are transmitted. In a dynamically changing radio frequency environment, however, information contained in some of the transmitted L2 PDUs, such as those associated with a radio frequency signal measurement, can change before the L2 PDU is correctly acknowledged. Thus, while retransmission of L2 PDUs that require acknowledgement can ensure proper reception, the retransmission can also result be unnecessary when newer values for the communicated information in the L2 PDUs exist. 
       FIG. 9  illustrates communication  900  of a layer 2 PDU  902  through the communication protocol stack  600  shown in  FIG. 6 . A layer 3 SDU  902  can be generated by the signaling block  616  and transferred to the layer 2 LAC  606 , which can transfer the layer 3 SDU  902  as one or more layer 2 PDUs  904  to the MAC/PHY  602 / 604  layers for radio frequency transmission to the network  908 . An acknowledgement (ACK)  906  of the L2 PDU  904  by an endpoint in the network  908  can be received by the MAC/PHY  602 / 604  and passed to the layer 2 LAC  606 . As a single L3 SDU  903  can require multiple layer 2 PDUs  904  for transmission, each layer 2 PDU  904  can require a separate acknowledgement (and when not acknowledged, each layer 2 PDU  904  can be retransmitted separately). In a CDMA2000 system, each layer 2 PDU  904  can be retransmitted up to N1m times if no acknowledgement is received from the destination point. For each layer 2 PDU in transit and awaiting acknowledgement, the layer 2 LAC  606  can maintain retransmission counters and can declare a retransmission timeout after a number of failed retransmissions. In a typical CDMA2000 system, N1m can be set to 13 and layer 2 PDU retransmissions can be spaced approximately 400 ms apart in time. Thus a complete sequence of retransmissions for a single layer 2 PDU can take more than 5 seconds. By the time the last retransmission occurs, the radio frequency conditions of the wireless communication network  100  as measured by the mobile wireless communication device  106  can have changed substantially. In a CDMA2000 system, the layer 2 LAC  606  can declare a loss of a logical channel  614  on which the layer 2 PDU  904  can be transmitted if no acknowledgement is received after transmitting the layer 2 PDU  904  N1m times. A loss of a logical channel  614  can result in termination of one or more connections between the mobile wireless communication device  106  and the network  908 . 
     An exemplary layer 3 SDU  902  can include a pilot strength measurement message (PSMM) for a CDMA2000 system. The mobile wireless communication device  106  can measure the strength of signals sent on “pilot” channels by the BTS  506 / 510  in radio access network units  504 / 514  located within detectable range of the mobile wireless communication device  106 . The PSMM can include several different information fields including a pseudo-random sequence number (PN) that can represent a sector in a cellular network  100 , and a PN signal to interference strength Ec/Io. Each unique PN can represent a separate radio frequency link through which the mobile wireless communication device  106  can connect to the wireless communication network  100 . The PSMM can also include an indication of how the mobile wireless communication device  106  would like to classify the PN, for example whether to include it in a set of pilots to which the mobile wireless communication device  106  can connect. 
       FIG. 10  illustrates a state diagram  1000  for classifications of pilots that can be maintained by a mobile wireless communication device  106 . Each pilot known by the mobile wireless communication device  106  can be classified into one of three different sets. A neighbor set  1006  can include a set of neighbor base transceiver station pilots to which the mobile wireless communication device  106  can connect if there is sufficient signal strength. A candidate set  1004  can include a set of candidate base transceiver station pilots that satisfy a minimum strength level with which the mobile wireless communication device  106  can connect. An active set  1002  can include a set of active base transceiver station pilots to which the mobile wireless communication device  106  can be actively connected. The number of base transceiver station pilots included in the active set  1002  can be limited by the wireless communication network  100 , typically six pilots or less. The strength of each pilot received by the mobile wireless communication device  106  can be measured periodically, and the mobile wireless communication device  106  can indicate the pilot strength measurements to the wireless communication network  100  by sending pilot strength measurement messages (PSMM). 
     A pilot in the neighbor set  1006  can be added (state transition  1008 ) to the candidate set  1004  by the mobile wireless communication device  106  when the measured pilot signal strength exceeds a pre-determined add threshold for a pre-determined add time period. The mobile wireless communication device  106  can move the pilot from the neighbor set  1006  to the candidate set  1004  and inform the wireless communication network  100  of the pilot movement through a PSMM. The mobile wireless communication device  106  can “add” a pilot to the candidate set  1004  without receiving an explicit command to do so by the wireless communication network  100 . A pilot in the candidate set  1004  can be dropped (state transition  1014 ) to the neighbor set  1006  when measured pilot signal strength falls below a pre-determined drop threshold for a pre-determined drop period. The mobile wireless communication device  106  can move the pilot from the neighbor set  1006  to the candidate set  1004 . The mobile wireless communication device  106  can inform the wireless communication network  100  of the pilot movement through a PSMM, although informing the wireless communication network  100  can be optional and not required. In representative embodiments, movement of a pilot between the candidate set  1004  and the neighbor set  1006  can occur without informing the wireless communication network  100 . The mobile wireless communication device  106  can “drop” a pilot from the candidate set  1004  without receiving an explicit command to do so by the wireless communication network  100 . Movement of pilots between the candidate set  1004  and an active set  1002 , however, can require confirmation commands from the wireless communication network  100 . In representative embodiments, movement of a pilot between the candidate set  1004  and an active set  1002  will always include an exchange of one or more messages with the wireless communication network  100 . 
     The mobile wireless communication device  106  can detect that a pilot in the candidate set  1004  has a signal strength that satisfies a set of performance criteria for a pre-determined period of time (the performance criteria can include signal strength level as well as changes to signal strength over time, such as a slope of a measured signal strength curve). The threshold for a pilot to be promoted from the candidate set  1004  to the active set  1002  can be higher than the threshold for a pilot to be added to the candidate set from the neighbor set  1006 . The mobile wireless communication device  106  can send a PSMM to the wireless communication network  100  requesting to promote (state transition  1010 ) the pilot from the candidate set  1004  to the active set  1002 . The pilot can be promoted to the active set  1002  by the mobile wireless communication device  106  after receiving a handoff confirmation message from the wireless communication network  100 . When no handoff confirmation message is received, the pilot can remain in the candidate set  1004 . 
     Similar to promoting a pilot into the active set  1002 , a pilot can be demoted from the active set  1002  to the candidate set  1004 . The mobile wireless communication device  106  can detect that a pilot in the active set  1002  has a signal strength that falls below a pre-determined threshold level for a pre-determined period of time. The threshold for a pilot to be demoted can be different from the threshold for a pilot to be promoted. The mobile wireless communication device  106  can send a PSMM to the wireless communication network  100  requesting to demote (state transition  1012 ) the pilot from the active set  1002  to the candidate set  1004 . A pilot in the active set  1002  can be demoted to the candidate set  1004  in response to receiving a handoff confirmation message from the wireless communication network  100 . Thus, movement of pilots between the neighbor set  1006  and the candidate set  1004  can occur without confirmation. The mobile wireless communication device  106  can inform the wireless communication network  100  by sending one or more PSMM of the movement of the pilots; however informing the wireless communication network  100  can be optional and is not required. Movement of pilots between the active set  1002  and the candidate set  1004 , however, can require confirmation from the wireless communication network  100  to the mobile wireless communication device  106 . In representative embodiments, confirmation to move the pilots between the active set  1002  and the candidate set will always be sent or the movement will not occur. One or more PSMM can be sent by the mobile wireless communication device  106  to the wireless communication network  100 , and confirmations can be returned from the wireless communication network  100  to the mobile wireless communication device  106 . With a dynamically changing radio frequency environment, particularly during periods of low received signal quality during which PSMM can require multiple retransmissions before an acknowledgement is received by the mobile wireless communication device  106 , a decision to move a pilot can be superseded by a new decision to not move the pilot. In this case, the “old” pilot strength measurement message can be discarded, and a “new” pilot strength measurement message can be sent instead. 
       FIG. 11  illustrates a graph  1100  with movement of two pilots between sets in the mobile wireless communication device  106 . Pilot signal strength can be measured and reported as a signal to noise/interference ratio Ec/Io  1102  as indicated. (Alternative measures such as received signal strength or other signal quality metrics can also be used in place of the Ec/Io  1102  shown herein for illustration.) An add threshold  1104  and a drop threshold  1106  can be set for different levels of Ec/Io  1102 . Initially a first pilot # 1  can have a high Ec/Io  1102  while a second pilot # 2  can have a low Ec/Io  1102 . The first pilot # 1  can be in the active set, while the second pilot # 2  can be in the neighbor set, as shown initially at the left side of the graph  1100 . The second pilot # 2  signal, as received and measured by the mobile wireless communication device  106 , can then be increasing over time and surpass the add threshold  1104 . The mobile wireless communication device  106  can add the second pilot # 2  to the candidate set (CS) from the neighbor set (NS) at time  1108  when the second pilot # 2  measured Ec/Io can surpass the add threshold  1104 . After a pre-determined period of time, during which the second pilot # 2  Ec/Io  1102  can be above the add threshold continuously, the mobile wireless communication device  106  can request to promote the second pilot # 2  to the active set by sending a PSMM to the wireless communication network  100  at time  1110 . In response to receiving a handoff direction message (HDM) from the wireless communication network  100 , the mobile wireless communication device  106  can promote the second pilot # 2  to the active set at time  1112 . Following the promotion of the second pilot # 2 , the first pilot # 1  and the second pilot # 2  can both be in the active set. 
     Signal conditions received at the mobile wireless communication device  106  can subsequently continue to change. With changing signal conditions, the first pilot # 1  can degrade in signal quality while the second pilot # 2  can maintain a relatively high signal quality. This can occur, for example, when the mobile wireless communication device  106  moves closer to the BTS from which the second pilot # 2  emanates and further away from the BTS from which the first pilot # 1  is transmitted. The mobile wireless communication device  106  can continuously measure the Ec/Io for each pilot received to compare the quality of signals received from pilots in the active set. Relatively poorer performing pilots can be demoted when appropriately determined by the mobile wireless communication device  106  and confirmed by the wireless communication network  100 . As shown in  FIG. 11 , at time  1114 , the mobile wireless communication device  106  can request to demote the first pilot # 1  from the active set to the candidate set when the first pilot # 1  falls below a drop threshold  1106  by sending a second PSMM to the wireless communication network  100 . In response to a handoff direction message confirmation from the wireless communication network  100 , the mobile wireless communication device  106 , at time  1116 , can demote the first pilot # 1  from the active set to the candidate set. Subsequently the signal quality of the first pilot # 1  can continue to decline. After measuring the signal quality of the first pilot # 1  falling below a drop threshold  1106  for a pre-determined period of time, the mobile wireless communication device  106  can drop the first pilot # 1  from the candidate set to the neighbor set at time  1118 . 
       FIG. 12  illustrates a representative method  1200  to control measurement messaging in a mobile wireless communication device  106 . The mobile wireless communication device  106  can measure one or more radio frequency (RF) parameters in step  1202 . The radio frequency parameters can be measured based on signals received from one or more different base transceiver stations located in a wireless communication network  100 . In step  1204 , the mobile wireless communication device  106  can transmit a first measurement message to the wireless communication network  100 . The first measurement message can contain information for requesting a set management change based on the measured RF parameters. A request for a set management change can include adding or dropping radio frequency resources in use for communication between the mobile wireless communication device  106  and the wireless communication network  100 . Information in the first measurement message can also include reporting measured signal strength and quality. In step  1206 , the mobile wireless communication device  106  can determine if an acknowledgement has been received from the wireless communication network  100  to the transmitted first measurement message within a pre-determined waiting time period. If an acknowledgement has been received then the process can end. If, however, no acknowledgement has been received within the pre-determined waiting time period, the mobile wireless communication device  106  can determine if one or more of the RF parameters measured in step  1202  have changed after the first measurement message was transmitted. A change in RF parameters can be significantly large that the first measurement message can be no longer valid. If the measured RF parameter change is not significantly large, then in step  1210  the mobile wireless communication device  106  can retransmit the first measurement message and repeat the cycle. If, however, the measured RF parameter change is significantly large then the mobile wireless communication device  106  can stop transmission of the first measurement message to the wireless communication network  100  in step  1212 , as the information in the first measurement message can be no longer valid. Subsequently, in step  1214 , the mobile wireless communication device  106  can transmit instead a second measurement message to the wireless communication network  100  that supersedes the first measurement message. In one embodiment, the first and second measurement messages can be layer 3 SDUs transmitted as a numbered sequence of layer 2 PDUs to the wireless communication network  100 . In one embodiment, after stopping transmission of the first measurement message, a reset message can be sent to reset layer 2 PDU sequence numbers used by the mobile wireless communication device  106 . 
       FIG. 13  illustrates a second representative method  1300  for controlling measurement messaging between a mobile wireless communication device  106  and a wireless communication network  100 . In step  1302  a first measurement message can be transmitted by the wireless communication device  106  to the wireless communication network. In step  1304 , the transmitted first measurement message can be stored in the mobile wireless communication device  106  pending acknowledgement from the wireless communication network  100 . In step  1306 , the mobile wireless communication device  106  can determine if an acknowledgement has been received to the transmitted first measurement message within a pre-determined time period. If yes, then the method can end. If no, then in step  1308 , the mobile wireless communication device  106  can determine if one or more measured radio frequency parameters have changed significantly during the interim waiting period while the first measurement message is pending acknowledgement. If an RF parameter has not changed significantly then the mobile wireless communication device  106  in step  1310  can retransmit the first measurement message. If an RF parameter has changed significantly during the interim period awaiting acknowledgement, the mobile wireless communication device  106  can delete the stored first measurement message in step  1312  and transmit instead a second measurement message in step  1314 . In one embodiment, the first and second measurement messages can be layer 3 SDUs transmitted as a numbered sequence of layer 2 PDUs to the wireless communication network  100 . In one embodiment, after deleting the first measurement message, a reset message can be sent to reset layer 2 PDU sequence numbers used by the mobile wireless communication device  106 . 
     As described in  FIGS. 10 and 11 , a set of radio resources can be managed by the mobile wireless communication device  106  based on measurements of signals received by the mobile wireless communication device  106  from the wireless communication network  100 . The measured radio frequency signals received by the mobile wireless communication device  106  can be divided into at least two distinct sets, a first set used for active connections and a second set used for potential connections. In a representative embodiment, the first set can be an active set  1002  of pilot signals transmitted by base transceiver stations  506 / 510  in the wireless communication network  100 , and the second set can be a candidate of pilot signals. Movement of the signals between the distinct sets can be based on the measurements and on an exchange of messages between the mobile wireless communication device  106  and the wireless communication network  100 . Movement between some of the sets can be based on measurements alone, while movement between some of the sets can require confirmation messages from the wireless communication network  100  to the mobile wireless communication device  106  following a request to move the signals. As the radio frequency environment experienced by the mobile wireless communication device  106  can vary over time, if the exchange of messages to effect a move takes longer than a significant variation in the received signal measurements, a move requested can become out of date and no longer relevant. Retransmission of outdated messages by the mobile wireless communication device  106  can be stopped, and new messages can be formed and transmitted instead. When messages are communicated as numbered sequences, the mobile wireless communication device  106  can send a reset message to the wireless communication network to indicate a reset of the sequence numbering after stopping retransmission of outdated messages. 
       FIG. 14  illustrates a representative method  1400  to manage radio resources by a mobile wireless communication device  106  connected to a wireless communication network  100 . The mobile wireless communication device  106 , in step  1402 , can classify multiple radio resources available to the mobile wireless communication device  106  into at least two distinct sets. The classification can include an active set that includes radio resources that can be actively used for active connections and a candidate set that includes radio resources that can potentially by used for active connections (but are not used when in the candidate set). In step  1404 , the mobile wireless communication device  106  can measure a signal quality of at least one of the radio resources. The measured radio resource can be a pilot signal transmitted by a base transceiver station in a radio network subsystem  104 / 108  of the wireless communication network  100 . The mobile wireless communication device  106  can form a first measurement message that includes information about the measured radio resource and transmit at least a portion of the first measurement message in step  1406 . Additional portions of the first measurement message (if divided into multiple portions) can be subsequently transmitted by the mobile wireless communication device  106  to the wireless communication network  100 . 
     After transmitting each portion of the first measurement message, the mobile wireless communication device  106  can await an acknowledgement that the portion of the first measurement message was received by the wireless communication network  100 . If it is determined that the acknowledgement is received in step  1408 , then the method can end. If, however, it is determined that no acknowledgement to the portion of the first measurement message transmitted to the wireless communication network  100  has been received, then in step  1410 , the mobile wireless communication device  106  can detect whether a signal quality of the measured radio resource has changed. A change can be considered to have occurred if the measured signal quality of the radio resource exceeds a threshold. The threshold can be a dynamic threshold that depends on the signal quality measured and on a recent history of measured values. Alternatively the threshold can be based on parameters and values for those parameters specified by the wireless communication network  100 . When no signal quality change is detected, the mobile wireless communication device  106  can re-check if an acknowledgement to the previously transmitted portion of the first measurement message was received. In step  1412 , the mobile wireless communication device  106  can stop transmission of the unacknowledged portion of the first measurement message. In step  1414 , the mobile wireless communication device  106  can transmit a portion of a second measurement message to the base transceiver station in the radio network subsystem  104 / 108  of the wireless communication network  100 . The second measurement message can include updated information about the measured radio resources. 
     In representative embodiments, the first measurement message can include a transfer request for one of the measured radio resources between two of the distinctly classified sets. The first measurement message can request a promotion of one of the radio resources from a potential set to an active set. Alternatively the first measurement message can request a demotion of one of the radio resources from the active set to the potential set. In addition to the steps shown in  FIG. 14 , the method can further include transferring one of the measured radio resources from a set of unused connections to the set of potential connections based after measuring the radio resources. In a representative embodiment, the first measurement message can be a pilot strength measurement message. In a representative embodiment, the first and second measurement messages can be layer 3 SDUs transmitted as a numbered sequence of layer 2 PDUs to the wireless communication network  100 . In a representative embodiment, after deleting the first measurement message, a reset message can be sent to reset layer 2 PDU sequence numbers used by the mobile wireless communication device  106 . 
       FIG. 15  illustrates a second method  1500  for managing radio resources in a mobile wireless communication device  106  that can be in communication with one or more radio network subsystems  104 / 108  in the wireless communication network  100 . In step  1502 , the mobile wireless communication device  106  can measure radio frequency parameters of signals received from one or more radio network subsystems in the wireless communication network  100 . In step  1504 , the mobile wireless communication device  106  can classify the measured radio frequency signals received from the radio network subsystems into at least two distinct sets. A first set can be used for those signals associated with active connections. A second set can be used for those signals associated with potential connections. Additional sets can be used, such as those for signals that are not potential or active connections. Classification can be based on the measured radio frequency parameters. Representative embodiments of the method can use measured radio frequency parameters that include signal strength (e.g. RSCP received signal code power) and signal quality (Ec/Io signal to interference ratio). Based on the measurements performed in step  1504 , the mobile wireless communication device  106 , in step  1506 , can request promotion of one of the radio frequency signals from the potential set to the active set. The promotion can be included as a request in a measurement message sent to the wireless communication network  100 . The measurement message can be sent as a sequence of one or more protocol data units. The measurement message can require an acknowledgement from the wireless communication network  100 . In some embodiments, the promotion can occur only after the acknowledgement can be received by the mobile wireless communication device  106 . 
     In step  1508 , the mobile wireless communication device  106  can determine if an acknowledgement has been received to the transmitted measurement message. If an acknowledgement has been received, then the method can terminate. If, however no acknowledgement has been received, then the mobile wireless communication device  106  can determine if a measured signal quality from one of the radio resources has changed and exceed a predetermined threshold. If no change to the measured signal quality has occurred, the mobile wireless communication device  106  can repeat the steps of testing for an acknowledgement and a change in signal quality. If a change in signal quality is detected in step  1510 , then in step  1512 , the mobile wireless communication device  106  can cancel the promotion request. The promotion request can be included in a first measurement message, and the cancellation request can be included in a second measurement message sent by the mobile wireless communication device  106  to the wireless communication network  100 . In a representative embodiment, the measurement messages can be formed as layer 3 SDUs and transmitted as numbered sequences of layer 2 PDUs to the wireless communication network  100 . In a representative embodiment, after cancelling the promotion, a reset message can be sent to the wireless communication network  100  to reset layer 2 PDU sequence numbers used by the mobile wireless communication device  106 . 
     Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line used to fabricate thermoplastic molded parts. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, DVDs, magnetic tape, optical data storage devices, and carrier waves. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. Thus, the foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings. 
     The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.

Metadata:
Filing Date: 20110107
Publication Date: 20130806
Grant Date: 20130806
Priority Date: 20110107
Inventors: VASHI PRASHANT H.
NUKALA GAURAV R.
GARG SHARAD
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W72/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L1/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L1/188", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W24/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L1/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L1/188", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W24/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L1/1887", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L1/1887", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 46455655