HK1112542A - Default configurations with differential encoding in a wireless communication system - Google Patents

Description

Default configuration and differential encoding in a wireless communication system

Priority as required in accordance with 35 U.S.C § 119

Priority of this patent application for provisional application serial No. 60/601,429 entitled "DefaultConfigurations with Differential Encoding in a Wireless communication system" filed on 8, 12/2004, which is assigned to the assignee hereof and expressly incorporated herein by reference.

Technical Field

The present disclosure relates generally to communication, and more specifically to techniques for configuring and reconfiguring calls in a wireless communication system.

Background

Wireless communication systems are widely deployed to provide various communication services such as voice, video, data, messaging, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and/or transmit power).

A wireless device (e.g., a cellular telephone) may operate in one of several modes, such as an idle mode or a connected mode, at any given moment. In idle mode, the wireless device may monitor a paging channel for paging messages that alert the wireless device to the occurrence of an incoming call and/or overhead messages that carry system information and other information for the wireless device. In connected mode, the wireless device may actively exchange data with one or more base stations in the system for, for example, a voice or data call.

The wireless device may perform configuration when transitioning from idle mode to connected mode and may perform reconfiguration when in connected mode. Configuration refers to setting various parameters for communication. Reconfiguration refers to changing parameters for communication. Reconfiguration may be performed for various reasons, such as to change data rates, to change or add services, to change the quality of service (QoS) of existing services, to switch from one frequency to another (e.g., to balance system load), to change states within a connected mode (e.g., to conserve power of the wireless device), and so forth.

To perform the reconfiguration, the wireless device and the wireless system typically exchange signaling or messages to communicate various parameters for transmission on the downlink and uplink. These parameters may indicate: such as the channel, data rate, coding scheme, data block size, etc. used for each link. The reconfiguration message may be long, especially when there are many parameters to exchange. Typically, long reconfiguration messages, which take a long time to transmit and are likely to require retransmission in order to be successfully received, also consume valuable radio resources and cause long delays in reconfiguration, all of which are undesirable.

Accordingly, there is a need in the art for techniques to more efficiently perform configuration and reconfiguration in a wireless communication system.

Disclosure of Invention

Techniques for efficiently configuring and reconfiguring calls (e.g., voice and/or data calls) are described herein. These techniques use a set of default configurations and differential encoding to reduce the amount of signaling sent to configure or reconfigure a call. The default configuration is a configuration that is known in advance by both the wireless system and the wireless device, and the configuration is a set of values for a set of parameters used for communication. The set of default configurations may be defined in a standard supported by both the wireless system and the wireless device. Differential encoding refers to employing a default configuration and the difference between the selected configuration and the default configuration (if any) to communicate the configuration selected for use.

According to one embodiment of the invention, an apparatus is described that includes a memory and a processor. The memory stores a set of default configurations such that each default configuration is associated with a respective set of parameter values for communication. The processor selects a configuration for communication with the wireless device, determines a difference, if any, between the selected configuration and the default configuration, and sends an identification of the default configuration and the difference, if any, to communicate the selected configuration.

According to another embodiment, a method is provided in which a configuration for communicating with a wireless device is selected. A default configuration is identified from a set of default configurations. A difference, if any, between the selected configuration and the default configuration is determined. The identification of the default configuration and the difference (if any) are sent to communicate the selected configuration.

According to yet another embodiment, an apparatus is described that includes means for selecting a configuration for communicating with a wireless device, means for identifying a default configuration from a set of default configurations, means for determining a difference, if any, between the selected configuration and the default configuration, and means for sending the identification of the default configuration and the difference, if any, to communicate the selected configuration.

According to yet another embodiment, a processor-readable medium is described that stores instructions for: the method includes selecting a configuration for communication with the wireless device, identifying a default configuration from a set of default configurations, determining a difference, if any, between the selected configuration and the default configuration, and transmitting the identification of the default configuration and the difference, if any, to communicate the selected configuration.

According to yet another embodiment, an apparatus is described that includes a memory and a processor. The memory stores a set of default configurations. The processor receives an indication of a change in communication requirements of a wireless device operating in a connected mode, selects a default configuration from a set of default configurations based on the communication requirements, and sends the default configuration to the wireless device.

According to yet another embodiment, a method is provided in which an indication of a change in communication requirements of a wireless device operating in a connected mode is received. A default configuration is selected from a set of default configurations based on communication requirements and transmitted to the wireless device.

According to yet another embodiment, an apparatus is described that includes means for receiving an indication of a change in communication requirements of a wireless device operating in a connected mode, means for selecting a default configuration from a set of default configurations based on the communication requirements, and means for transmitting the default configuration to the wireless device.

According to yet another embodiment, an apparatus is described that includes a memory and a processor. The memory stores a set of default configurations. The processor receives a message containing an identification of the default configuration, obtains the default configuration from the memory based on the identification, determines whether the message contains a difference between the default configuration and the selected configuration, and replaces the value of the default configuration with the difference sent in the message, if any.

According to yet another embodiment, a method is provided in which a message is received that contains an identification of a default configuration. A default configuration is obtained (e.g., from memory) based on the identification. It is determined whether the message contains a difference between the default configuration and the selected configuration. The difference sent in the message (if present) is used to replace the default configuration value.

According to yet another embodiment, an apparatus is described that includes means for receiving a message containing an identification of a default configuration, means for obtaining the default configuration based on the identification, means for determining whether the message contains a difference between the default configuration and a selected configuration, and means for replacing a value of the default configuration with the difference sent in the message (if the difference exists).

According to yet another embodiment, a processor-readable medium storing instructions for performing the following operations in a wireless device is described: receiving a message containing an identification of a default configuration, obtaining the default configuration based on the identification, determining whether the message contains a difference between the default configuration and a selected configuration, and replacing a value of the default configuration with the difference sent in the message, if any.

According to yet another embodiment, an apparatus is described that includes a memory and a processor. The memory stores a set of default configurations. The processor receives a reconfiguration message in response to a change in communication requirements of a wireless device operating in a connected mode, extracts an identification of a default configuration from the reconfiguration message, obtains the default configuration from the memory based on the identification, and uses the default configuration for communication.

According to yet another embodiment, a method is provided in which a reconfiguration message is received in response to a change in communication requirements of a wireless device operating in a connected mode. An identification of the default configuration is extracted from the reconfiguration message. A default configuration is obtained from the memory based on the identification and used for communication.

According to yet another embodiment, an apparatus is described that includes means for receiving a reconfiguration message in response to a change in communication requirements of a wireless device operating in a connected mode, means for extracting an identification of a default configuration from the reconfiguration message, means for obtaining the default configuration from memory based on the identification, and means for using the default configuration for communication.

Aspects and embodiments of the invention will be described in more detail below.

Drawings

Figure 1 shows a UMTS Terrestrial Radio Access Network (UTRAN);

fig. 2 shows a protocol stack defined by 3GPP release 6;

FIG. 3 shows a state diagram of different states and modes of a UE;

FIG. 4 shows a signaling flow for a reconfiguration process;

FIG. 5 illustrates a process for sending reconfiguration messages using default configuration and differential encoding;

FIG. 6 illustrates a process for receiving a reconfiguration message that has been sent using a default configuration and differential encoding;

FIG. 7 illustrates an exemplary reconfiguration message;

fig. 8 shows a block diagram of a UTRAN and a wireless device.

Detailed Description

The word "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as a preferred embodiment or as advantageous over other embodiments.

The techniques described herein may be used for various wireless communication systems such as Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, and so on. A CDMA system may implement one or more CDMA Radio Access Technologies (RATs), such as wideband CDMA (W-CDMA), CDMA2000, and so on. cdma2000 covers IS-2000, IS-856 and IS-95 standards. A TDMA system may implement one or more TDMA RATs, such as Global System for Mobile communications (GSM), digital advanced Mobile Phone System (D-AMP), and so forth. These different RATs and standards are known in the art. W-CDMA and GSM are described in documents from a consortium named "third Generation partnership project" (3 GPP). cdma2000 is described in a document from a consortium named "third generation partnership project 2" (3GPP 2). The 3GPP and 3GPP2 documents are publicly available. For clarity, the techniques herein are described below for a Universal Mobile Telecommunications System (UMTS) utilizing W-CDMA for over-the-air communication transmissions.

Fig. 1 shows a UMTS Terrestrial Radio Access Network (UTRAN)100, which includes a number of base stations that communicate with a number of wireless devices. For simplicity, only three base stations 110 and one wireless device 120 are shown in fig. 1. A base station is a fixed station and may also be referred to as a node B, a Base Transceiver Subsystem (BTS), an access point, or some other terminology. Each base station provides communication coverage for a particular geographic area. A base station and/or its coverage area may be referred to as a "cell" depending on the context in which the term is used. A wireless device may be fixed or mobile and may also be referred to as User Equipment (UE), a mobile station, a terminal, or some other terminology. A wireless device may communicate with one or more base stations on the downlink and/or uplink at any given moment depending on whether the wireless device is active, whether soft handoff is supported, and whether the wireless device is in soft handoff. The downlink (or forward link) refers to the communication link from the base stations to the wireless devices, and the uplink (or reverse link) refers to the communication link from the wireless devices to the base stations. A Radio Network Controller (RNC)130 is connected to and coordinates and controls the base stations 110. In the following description, the wireless device is referred to as a UE, and the network side (e.g., node B and RNC) is referred to as UTRAN.

Fig. 2 shows a protocol stack 200 defined by 3GPP release 6. The protocol stack 200 includes a Radio Resource Control (RRC) layer 210, a Radio Link Control (RLC) layer 220, a Medium Access Control (MAC) layer 230, and a physical layer 240. The RRC layer 21O is a sublayer of the L3 layer. The RLC layer 220 and MAC layer 230 are sublayers of the L2 layer commonly referred to as the data link layer. The physical layer 240 is commonly referred to as the L1 layer.

The RRC layer provides an information transfer service to a non-access stratum (NAS), which is a functional layer supporting traffic and signaling messages between the UE and a core network CN, to which the UTRAN interfaces. The RRC layer is also responsible for controlling the configuration of the L1 and L2 layers. The RLC layer provides reliability of data transmission and performs automatic retransmission of data. In the RLC layer, data is processed as if belonging to a logical channel. The MAC layer maps and/or multiplexes the logical channels onto the transport channels and processes (e.g., encodes, interleaves, and rate matches) the data for each transport channel. The physical layer provides a mechanism for transmitting data of the MAC layer and signaling of higher layers. The physical layer maps transport channels onto physical channels, processes (e.g., channelizes and scrambles) data for each physical channel, and performs power control for each set of physical channels.

On the network side, the physical layer is typically implemented at the node B, and the RLC, MAC and RRC layers are typically implemented at the RNC. The layers of 3GPP are described in various 3GPP documents.

Fig. 3 shows a state diagram 300 of states and modes of a UE in 3 GPP. For simplicity, the state diagram 300 only shows the relevant states and modes, and does not show all possible states and modes. After power on, the UE performs cell selection to find a suitable cell from which to receive service. The UE may then transition to idle mode 310, UTRA RRC connected mode 320, or GSM connected mode 330 depending on whether the UE has any activity and whether the UE is communicating with a UTRAN or GSM/EDGE radio Access network (GERAN). In idle mode, the UE has registered with the network, listens for paging messages, and updates its location to the network if necessary. The UE may perform operations to receive and/or transmit data with the UTRAN in UTRA RRC connected mode and with the GERAN in GSM connected mode, depending on its state and configuration. The UE may transition between UTRA RRC connected mode and GSM connected mode in order to perform a handover between UMTS and GSM.

When in UTRARRC connected mode, the UE may be in one of four possible RRC states: CELL _ DCH state 322, CELL _ FACH state 324, CELL _ PCH state 326, or URA _ PCH state 328, where DCH denotes dedicated transport channel, FACH denotes forward access channel, PCH denotes paging channel, URA denotes UTRAN registration area. Table 1 provides a brief description of the four RRC states. These modes and states are described in detail in 3GPP TS 25.331V 6.2.

TABLE 1

Status of state	Description of the invention
		CELL_DCH	Dedicated physical channels are assigned to the UE for uplink and downlink; and a combination of dedicated and shared transport channels is available to the UE.
CELL_PACH	No dedicated physical channel is assigned to the UE; a default common or shared transport channel on the uplink is allocated to the UE for accessing the network; and the UE continuously monitors signalling such as reconfiguration messages on the FACH on the downlink
		CELL _ PCH and URA _ PCH	No dedicated physical channel is assigned to the UE; the UE periodically monitors the PCH for paging messages; and UE is not allowed to transmit on the uplink

The UE may: (1) transitioning from an idle mode to a CELL _ DCH state or a CELL _ FACH state by performing a procedure of establishing an RRC connection; (2) transitioning from the CELL _ DCH state or the CELL _ FACH state to the idle mode by performing a procedure to release the RRC connection. The UE may: (1) transitioning from the CELL _ DCH state or the CELL _ FACH state to another state in UTRA RRC connected mode by performing a reconfiguration procedure; (2) it is also possible to transition between different configurations in the CELL _ DCH state by performing a reconfiguration procedure. The UTRAN may command the UE to be in one of four states in UTRA RRC connected mode based on the activity of the UE. The connection and reconfiguration procedures are described in 3GPP TS 25.331V 6.2. In fig. 3, the conversion in which reconfiguration is performed is shown by a solid line with a single arrow, and the conversion in which reconfiguration is not performed is shown by a broken line with a single arrow.

The 3GPP defines reconfiguration procedures for Radio Bearer (RB) reconfiguration, transport channel (TrCH) reconfiguration and physical channel reconfiguration. The radio bearer is a service provided by the L2 layer for transferring traffic data between the UE and the UTRAN. One or more radio bearers may be maintained by the UE and a peer entity on layer 2 in the UTRAN. Each radio bearer is associated with a specific configuration of logical channels, transport channels and physical channels. For example, the configuration of each radio bearer may describe the particular channel used, the rate of each channel, the channelization code (OVSF code) of the physical channel, and so on. The configuration of each radio bearer depends on the amount of activity at the UE. For example, (1) if the UE has data to transmit or receive, the UE may be placed in a CELL _ DCH state; or (2) the UE may be placed in the CELL _ FACH state if the UE has no data to transmit or receive. The UE may also change its configuration if the amount of activity changes. The configuration change of the UE is accomplished by performing a reconfiguration procedure.

Fig. 4 shows a signaling flow 400 for a reconfiguration process. The UTRAN initiates the reconfiguration procedure by sending a reconfiguration message, which may include: (1) information about the new configuration, e.g. new parameter values for the transport channels and the physical channels; (2) activation time, which is the time at which reconfiguration is to be applied. The UTRAN may initiate reconfiguration independently or may initiate reconfiguration in response to receiving signaling from the UE. Upon successful reception of the reconfiguration message, the UE performs reconfiguration of the channel being changed. The UTRAN similarly performs reconfiguration of the changed channel. Then, if the reconfiguration is successfully completed, the UE transmits a reconfiguration complete message (as shown in fig. 4), or if the reconfiguration is not successfully completed, the UE transmits a reconfiguration failure message (not shown in fig. 4).

Depending on which reconfiguration procedure is being performed, the UTRAN and the UE may send different messages. For example, a radio bearer reconfiguration message and a radio bearer reconfiguration complete message may be transmitted for radio bearer reconfiguration, a transport channel reconfiguration message and a transport channel reconfiguration complete message may be transmitted for transport channel reconfiguration, and a physical channel reconfiguration message and a physical channel reconfiguration complete message may be transmitted for physical channel reconfiguration. The reconfiguration message and reconfiguration complete message in fig. 4 would be generic messages that may correspond to any of the above-described message pairs or some other message pair.

The reconfiguration message typically contains various Information Elements (IEs) for various parameters related to the communication, as described below. For example, the radio bearer reconfiguration message may include a UE information element, a CN information element, a UTRAN mobility information element, a RB information element, a TrCH information element of downlink and uplink transport channels, and the like. Typically, the reconfiguration message is very large.

The reconfiguration message may be processed at the RLC layer as one or more Protocol Data Units (PDUs) depending on the size of the entire message. Each PDU may be transmitted in one Transmission Time Interval (TTI), where the TTI is used for signaling, typically 40 milliseconds (ms). The UTRAN transmits the entire reconfiguration message at once. The UE sends a Negative Acknowledgement (NAK) for each PDU that was not received correctly, and the UTRAN may retransmit the PDU one or more times until the PDU is received correctly by the UE. Table 2 shows the probability of receiving a reconfiguration message in error for different numbers of PDUs and different numbers of retransmissions. Table 2 assumes that the probability of erroneously receiving any given PDU is 5%, the probability of erroneously receiving any NAK is 5%, and the UE needs to correctly receive all PDUs of the message.

TABLE 2

Number of PDUs of message	0 retransmissions	1 retransmission	2 retransmissions	3 retransmissions
					1	5.00％	0.49％	0.05％	0.00％
2	9.75％	0.97％	0.10％	0.01％
					3	14.26％	1.46％	0.14％	0.01％
4	18.55％	1.94％	0.19％	0.02％
					5	22.62％	2.41％	0.24％	0.02％
6	26.49％	2.89％	0.28％	0.03％
					7	30.17％	3.36％	0.33％	0.03％
8	33.66％	3.83％	0.38％	0.04％

For the example shown in table 2, if the message consists of two or fewer PDUs, the UE will correctly receive the reconfiguration message with a probability of 99% or higher (corresponding to a message error probability of 1% or lower) after one retransmission, and if the message consists of more than two PDUs, the UE will correctly receive the reconfiguration message with a probability of 99% or higher after two retransmissions. Each PDU may be sent in one 40-ms TTI, the delay for retransmission may be 200ms, and the processing time at the UE may be 100 ms. In this case, the total transmission and processing time (with one retransmission) for a message with two PDUs can be calculated as: (2 × 40) for transmission 80ms + retransmission delay 200ms + UE processing time 100ms 380ms total delay. The total transmission and processing time (with two retransmissions) for a message with eight PDUs can be calculated as: (8 × 40) for transmission 320ms + 400ms for two retransmissions + UE processing time 100ms 820ms total delay. The size of the reconfiguration messages of 3GPP release 6 and earlier is commonly referred to as 4 to 8 PDUs.

The reconfiguration takes effect at the activation time indicated in the reconfiguration message. The UTRAN may set the activation time far enough into the future to allow sufficient transmission and retransmission times for the message so that the UE can reach a given expected correct reception probability. If the message is not received correctly after the activation time, the reconfiguration procedure will fail and in some cases (e.g. in case of reconfiguration of a compressed mode pattern) a radio link failure will occur. For the above example, the UTRAN may set the activation time to 380ms in the future if the reconfiguration message consists of two PDUs, or to 820ms in the future if the message consists of eight PDUs. These activation times ensure that the UE will correctly receive the reconfiguration message with a probability of 99% or higher. The activation time may be set further in the future to achieve a higher probability of correct reception (e.g., 99.9%).

The transmission time of the reconfiguration message may be a significant fraction of the total time of the reconfiguration process. For the above example, the transmission time of a short message (with two PDUs) is 380ms and the transmission time of a long message (with eight PDUs) is 820 ms. The difference between the transmission times of the short and long messages is 440 ms. The total time of the reconfiguration process can be reduced by a considerable amount by sending short reconfiguration messages. The above analysis does not take into account the amount of time required to perform asn.1 encoding at the UTRAN and the amount of time required to perform asn.1 decoding at the UE, if both are taken into account, more time reduction can be achieved when comparing the sending of short and long messages. Therefore, shorter reconfiguration messages are highly desirable in order to achieve the goal of minimizing the amount of time required to successfully deliver a message.

A set of default configurations may be defined for configurations that are typically used for communication. Each default configuration may be associated with a unique identification and a specific value for a specific set of parameters or information elements. Identification may also be referred to as an identifier, index, etc. A given default configuration may be efficiently sent in a message by including only the identity of the default configuration in the reconfiguration message (rather than including all information elements). The use of the default configuration can greatly reduce the message size, which can shorten the overall time for reconfiguration.

The set of default configurations may be defined for different classes of services, such as, for example, a session class, a flow class, an interactive class, and a background class. The conversational class is characterized by strict low delay and limited delay variation in order to maintain the temporal relationship between the information entities. Some exemplary applications that carry such traffic are voice, video, and video conferencing. The stream class is characterized by limited delay variation and some exemplary applications carrying this service are fax as well as streaming audio and streaming video. The interactive class is characterized by request/response patterns and retention of payload content (or low packet error rate). An exemplary application that carries such traffic is web browsing. The background class is characterized by a relative insensitivity to delivery time and retention of payload content. An exemplary application that carries such a service is background downloading of e-mail.

In one embodiment, default configurations for the session classes are defined first, as these configurations are typically the most demanding in terms of latency. Default configurations for the flow category, the interactive category, and the background category may then be defined as appropriate. This embodiment may reduce the size of the set of default configurations. In another embodiment, the configurations described in TS 25.993V 6.10 may be checked, and a subset of these configurations may be selected as a set of default configurations. In yet another embodiment, the default configuration set forth in TS 25.331V6.2 listed in Table 3 may be used as the default configuration. In table 3, CS represents circuit switching. The default configuration in TS 25.331V6.2 is conventionally used for: (1) establishing an RRC connection when transitioning from idle mode to connected mode; and (2) handover from GSM to UMTS. Typically, each default configuration is associated with a particular default value for a particular set of information elements. The information elements of the default configuration shown in table 3 and their default values are given in section 13.7 of TS 25.331V 6.2.

Default configuration in Table 3-TS 25.331

Default configuration identification	Description of the invention
		0	4kbps signaling
1	13.6kbps signaling
		2	7.95kbps Speech +3.4kbps Signaling
3	12.2kbps Speech +3.4kbps Signaling
		4	28.8kbps Session CS data +3.4kbps Signaling
5	32kbps Session CS data +3.4kbps Signaling
		6	64kbps conversational CS data +3.4kbps signaling
7	14.4kbps stream CS data +3.4kbps signaling
		8	28.8kbps stream CS data +3.4kbps signaling
9	57.6kbps stream CS data +3.4kbps signaling
		10	12.2kbps voice (multimodal) +3.4kbps signaling
11	10.2/6.7/5.9/4.75kbps speech +3.4kbps signaling
		12	7.4/6.7/5.9/4.75kbps speech +3.4kbps signaling
13	12.65/8.85/6.6kbps speech +3.4kbps signaling

Regardless of which set of default configurations is selected for use, there may be many situations where the configurations selected for use are not included in the default configuration set. In each such case, the selected configuration may be communicated by sending a reconfiguration message containing all the information elements of the configuration. As described above, the transmission time of the reconfiguration message may be long.

In one aspect, differential encoding may be used for selected configurations that are not included in the set of default configurations. Differential encoding allows for efficient transmission of selected configurations that do not exactly match any of the default configurations. This is accomplished by sending (1) an identification of the default configuration that most closely matches the selected configuration and (2) the difference between the selected configuration and the default configuration.

Typically, the selected configuration may be sent using minimal signaling, partial signaling, or full signaling. For minimum signaling, only the identity of the default configuration is sent. For partial signaling, an identification of the default configuration and a difference between the selected configuration and the default configuration are sent. For full signaling, the full selected configuration is sent.

Fig. 5 illustrates an embodiment of a process 500 for sending a reconfiguration message using default configuration and differential encoding. Initially, a configuration for communication is selected (block 512). The configuration may be selected in response to a change in the communication requirements of the UE, which may be caused by: a change in data rate, a change in service, a change in QoS, a change in state within UTRARRC connected mode, a transition from idle mode to UTRA RRC connected mode or GSM connected mode, a handover from one RAT to another RAT (e.g., from GSM to UMTS or UMTS to GSM), etc., or a combination thereof. The configuration may be selected by a radio resource management entity at the UTRAN based on the UE's communication requirements, network load, and/or other factors.

A determination is then made as to whether the selected configuration is one of the default configurations (block 514). If it is determined at block 516 that the selected configuration is the default configuration, then a reconfiguration message is efficiently formed using only the identification of the default configuration and the selected configuration is sent with minimal signaling (block 518).

If the selected configuration is not the default configuration and the result of block 516 is 'No', then the default configuration that most closely matches the selected configuration is identified (block 520). A difference between the selected configuration and the default configuration is determined (block 522). The difference may be one or more information elements. It is then determined whether it is more efficient to differentially encode the selected configuration than to transmit the entire selected configuration (524). If differential encoding is more efficient, a reconfiguration message is formed based on the identification of the default configuration and the determined difference, and the selected configuration is sent with partial signaling (block 526). Otherwise, all information elements of the selected configuration are employed to form a reconfiguration message and the selected configuration is transmitted with full signaling (block 528). The reconfiguration message is then sent to the UE (block 530).

Fig. 5 illustrates a specific process for generating a reconfiguration message using a default configuration and differential encoding. Differential encoding may also be performed in other ways. For example, the default configuration that most closely meets the communication requirements of the UE may be selected from the group of default configurations. The default configuration may be modified as needed to meet communication requirements. The change indicates the difference between the selected configuration and the default configuration and may be sent using partial signaling.

Fig. 6 illustrates an embodiment of a process 600 performed by a UE for receiving a reconfiguration message sent using a default configuration and differential encoding. Initially, a reconfiguration message is received from the UTRAN (block 612). A determination is made as to whether the reconfiguration message contains an identification of a default configuration (block 614). If the answer is 'Yes', a default configuration is obtained based on the identification (e.g., from memory within the UE), and a default value for the information element in the default configuration is determined (block 616). A determination is then made as to whether the reconfiguration message contains any additional information elements (block 618). If the answer is 'No', the selected configuration is sent with minimal signaling and a default configuration is provided as the selected configuration (block 620). Otherwise, if the answer at block 618 is 'Yes', the selected configuration is sent using partial signaling and the information element sent in the reconfiguration message is extracted (block 622). The value of the extracted information element is used to replace the default value of the corresponding information element in the default configuration (block 624). The default values for all other information elements in the default configuration are retained. Returning to block 614, if the default configuration is not sent in the reconfiguration message, the selected configuration is sent with full signaling and the information elements of the selected configuration are extracted from the message (block 626). Regardless of how the selected configuration is sent, the selected configuration is used for communication (block 630).

For the case where the selected configuration is slightly different from the default configuration, the use of the default configuration with differential encoding can greatly reduce the amount of signaling. For example, the UTRAN may select the exact same configuration as the default configuration except for the value of the "RLC Info" information element. In this case, the UTRAN may send to the UE an identification of the default configuration and only the "RLC Info" information element with the required values. The UE will obtain a default configuration based on the identity and will replace or override the contents of the "RLC Info" information element with the value received from the UTRAN. In case of differential encoding, if only a single parameter or a few parameters are changed with respect to the default configuration, only the changed parameters are transmitted instead of the complete configuration.

Fig. 7 illustrates an exemplary reconfiguration message 700 that supports default configuration and differential encoding. For this embodiment, the message 700 includes an information element 710 carrying an identification of the default configuration, an information element 720 carrying UE specific parameters, an information element 730 of the configuration information. A nested message structure may be used in which information elements at a given level may include one or more information elements at a next lower level. The UE-specific parameters are parameters that may vary from UE to UE and therefore may be sent explicitly in the reconfiguration message rather than being overridden by the default configuration. One example of a UE-specific parameter is the OVSF code of the physical channel allocated to the UE. This parameter may be sent explicitly in the reconfiguration message since no two UEs are using the same OVSF code at the same time. The information element 730 may: (1) omitted from the minimum signaling, (2) carry one or more information elements for partial signaling with a difference between the selected configuration and the default configuration, or (3) carry all information elements for the selected configuration for full signaling.

Tables 4, 5 and 6 list various information elements that may be included in the reconfiguration message. These information elements are described in TS25.331, v6.2.0. As shown in tables 4, 5 and 6, many information elements may need to be transmitted with full signaling, while only one or few information elements need to be transmitted with partial signaling, which may significantly shorten the message size.

Table 4-radio bearer information elements

Default configuration identification	Predefined RB configuration	RB information to be affected
			Downlink RLC STATUS information	RAB information	RB information to be reconfigured
PDCP context relocation information	RAB information Post	RB information to be released
			PDCP information	RAB information for setup	RB information to be set
PDCP SN information	RAB information to be reconfigured	RB mapping information
			Polling information	NAS synchronization indicator	RB with PDCP information
Predefined configuration identification	RB activation time information	RLC information
			Predefined configuration state information	RB COUNT-C MSB information	Signaling RB information to be set
Compressed predefined configuration state information	RB COUNT-C information	Transmission RLC discard
			Predefined configuration value tags	RB identification

Table 5-transmission CH information element

Added or reconfigured DLTrCH information	MAC-d flow identification	TFCS cancellation information
			Added or reconfigured MAC-d flows	Power offset information	Transmission channel identification
Added or reconfigured UL	Predefined TrCH information	Transport format combination

Trch information
			CPCH set ID	Quality target	Transport format combination set
Deleted DLTrCH information	Semi-static transport format information	Transport format combination set identification
			Deleted ULTrCH information	TFCI field 2 information	Transport format combination subsets
DL transport channel information common to all transport channels	TFCS explicit configuration	Transport format set
			DRAC static information	TFCS information of DSCH (TFCI Range method)	UL transport channel information common to all transport channels
HARQ information	TFCS reconfiguration/addition information

Table 6-physical CH information element

AC to ASC mapping	CPCH status indication mode	Downlink information per radio link
			AICH information	CSICH Power offset	Downlink information per radio link Post
AICH power offset	Default DPCH offset value	Downlink PDSCH information
			Dispatching cycle information	Downlink channelization codes	Downlink rate matching constraint information
Alpha	Downlink DPCH information common to all RLs	Downlink time slots and codes
			ASC settings	Downlink DPCH information common to all RL Posts	DPCH compression mode information
CCTrCH power control information	Downlink DPCH information common to all rlpre	DPCH compression mode status information
			Cell and channel identification information	Downlink DPCH information per RL	Dynamic persistence level
Cell parameter Id	Downlink DPCH information per RL Post	FPACH information
			Common time slot information	Downlink DPCH power control information	Frequency information
Constant value	Downlink HS-PDSCHInformation	HS-PDSCH Midamble configuration
			Constant value TDD	Downlink information common to all radio links	HS-PDSCH time slot configuration
CPCH persistence level	All radio links Post are common	HS-SCCH information

	Having downlink information
			CPCH set information	Downlink information common to all radio links Pre

An exemplary implementation of a default configuration using asn.1 coding as defined in 3GPP release 6 is shown below, where "R6" and "R6" represent 3GPP release 6.

r6message∷＝SEQUENCE{

CHOICE{defaultConfiguration1，

defaultConfiguration2，

defaultConfiguration3，

…

defaultConfigurationN} OPTIONAL

parametersUEspecific ParametersUEspecific OPTIONAL

r6message-IEs R6message-IEs OPTIONAL

}

R6message-IEs∷＝SEQUENCE{

informationElement1 InformatIonElement1 OPTIONAL，

informatIonElement2 InformatIonElement2 OPTIONAL，

informatIonElement3 InformatIonElement3 OPTIONAL，

…

informatIonElementM InformationElementM OPTIONAL，

}

In the above implementation, "CHOICE" is an information element that can take one of N values of N default configurations, where N > 1. The "parameteruespecific" information element carries user-specific parameters and has a format defined by a "parameteruespecific" structure. The "R6 message-IEs" information element carries the information elements of the selected configuration and has a format defined by the "R6 message-IEs" structure. The "R6 message-IEs" structure is a sequence of M optional information elements having a format defined by the "information element 1" structure through the "information element M" structure.

If the default configuration is not used, the "CHOICE" information element is not included in the reconfiguration message. The normal sending of the reconfiguration message will be used and will include all relevant information elements in the "r 6 message-IEs" information element and may also include the "parameters specific" information element.

If a default configuration is used, the default configuration will be indicated by the "CHOICE" information element, and UE specific parameters will be included in the "parameters specific" information element, if needed. The "r 6 message-IEs" information element may be used to send a value different from the default value of the default configuration. For example, if "informationElement 2" is the only information element that is different from the default configuration, then "informationElement 2" may only be included in the reconfiguration message.

The set of default configurations may change over time for various reasons. For example, some default configurations may not be used by any UTRAN, and it may be desirable to cancel these configurations. As another example, it may be desirable to extend the set of default configurations to include other useful configurations. In one embodiment, the new configuration may be added to the default configuration group to get a new version, but the configurations already included in the group are not cancelled. For this embodiment, the new version of the default configuration group is an extended set of the previous version of the default configuration group and is backward compatible with the previous version of the default configuration group. The fact that the default configuration is "permanent" may be taken into account in selecting the configurations included in the default configuration group. This embodiment may simplify the use of default configurations and may also simplify interoperability testing. In another embodiment, a set of default configurations may be defined for each new version, and a default configuration version may be assigned to the set of default configurations. The UE may store a set of default configurations for the versions supported by the UE. The UTRAN may store different sets of default configurations of different versions supported by the UTRAN, for example in a data structure designed to efficiently store these default configurations. For each UE, the UTRAN uses a default configuration set supported by the UE.

It may be mandatory that only the UE, only the UTRAN, or both the UE and UTRAN support the default configuration and differential coding.

Fig. 8 shows an embodiment of a UTRAN and a wireless device (UE) 120. Each processing unit at the UTRAN may reside at a node B or RNC. On the downlink, a Transmit (TX) data processor 810 at the UTRAN formats, codes, and interleaves signaling and data for UE 120. A Modulator (MOD)812 channelizes/spreads, scrambles, and modulates the output from TX data processor 810 and provides a stream of chips. Processing for signaling and data is described in 3GPP TS 25.321, TS 25.308, TS 25.212, and other 3GPP documents. A transmitter unit (TMTR)814 converts the stream of chips into an analog signal, amplifies, filters, and frequency upconverts the analog signal and generates a downlink signal, which is transmitted via an antenna 816. The UTRAN may transmit signaling and data to multiple UEs simultaneously, but this is not shown in fig. 8 for simplicity.

At UE 120, an antenna 852 receives the downlink signal and provides a received signal to a receiver unit (RCVR) 854. Receiver unit 854 filters, amplifies, frequency downconverts, and digitizes the received signal and provides data samples. A demodulator (DEMOD)856 descrambles, channelizes/despreads, and demodulates the data samples and provides symbol estimates. Demodulator 856 may implement a rake receiver that is capable of processing multiple samples (or multipath components) of the received signal. A Receive (RX) data processor 858 deinterleaves and decodes the symbol estimates, examines the received PDUs, and provides decoded data. The processing by demodulator 856 and RX data processor 858 is complementary to the processing by modulator 812 and TX data processor 810, respectively. The UTRAN and the UE perform a process of downlink transmission according to downlink logical channels, transport channels, and physical channels configured for the UE.

On the uplink, signaling and data are processed by a TX data processor 870, further processed by a modulator 872, conditioned by a transmitter unit 874, and transmitted via antenna 852. At UTRAN, the uplink signals are received by antennas 816, conditioned by receiver units 830, processed by demodulators 832, and further processed by an RX data processor 834 to recover the uplink signaling and data. The UTRAN and the UE perform a process of uplink transmission according to uplink logical channels, transport channels, and physical channels configured for the UE.

Controllers/processors 820 and 860 control operation at the UTRAN and UE, respectively. Memories 822 and 862 store data and codes used by controller/processors 820 and 860, respectively. Fig. 8 illustrates an RRC layer implemented by controllers/processors 820 and 860, an RLC and MAC layer implemented by TX data processors 810 and 870 and RX data processors 834 and 858, and a physical layer (L1 layer) implemented by modulators 812 and 872 and demodulators 832 and 856. In general, these layers may be implemented by any of the processing units shown in FIG. 8.

To perform reconfiguration, the UTRAN transmits a reconfiguration message to the UE. Controllers/processors 820 and 860 may perform reconfiguration at the UTRAN and the UE, respectively. After completing the reconfiguration, the UE transmits a reconfiguration complete message to the UTRAN.

For clarity, techniques using default configurations and differential coding have been described primarily for reconfiguration in UTRAN. In general, these techniques may be used to configure calls, reconfigure calls, and so on. A call may also be referred to as a session or some other terminology. These techniques may also be used for other CDMA networks (which may implement other CDMA standards) and other types of wireless communication networks (e.g., TDMA and FDMA networks).

The techniques described herein may be implemented by various means. For example, these techniques may be implemented in hardware, software, or a combination thereof. For a hardware implementation, the processing units used to configure and reconfigure calls at the network end may be implemented within one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, or a combination thereof. The processing unit at the UE may also be implemented in one or more ASICs, DSPs, processors, and the like.

For a software implementation, the techniques described herein may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit (e.g., memory unit 822 or 862 in fig. 8) and executed by a processor (e.g., processor 820 or 860). The memory unit may be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (48)

1. An apparatus, comprising:

a memory storing a set of default configurations, each default configuration being associated with a respective set of parameter values for communication; and

a processor that selects a configuration for communication with a wireless device, determines a difference between the selected configuration and a default configuration of the set of default configurations if the difference exists, and sends an identification of the default configuration and the difference to communicate the selected configuration if the difference exists.

2. The apparatus of claim 1, wherein each default configuration is associated with a default value for a corresponding set of information elements, the default value being the set of parameter values for the default configuration.

3. The device of claim 2, wherein the processor determines information elements having different values in the selected configuration and the default configuration.

4. The device of claim 3, wherein the processor forms a reconfiguration message with the identification of the default configuration and the information element having a different value.

5. The device of claim 4, wherein the processor further forms the reconfiguration message using at least one parameter specific to the wireless device.

6. The device of claim 1, wherein the processor only sends the identification of the default configuration if there is no difference between the selected configuration and the default configuration.

7. The device of claim 1, wherein if the difference exceeds a threshold, the processor sends the selected configuration without sending the default configuration and the difference.

8. The device of claim 1, wherein the processor selects the configuration in response to a change in communication requirements.

9. The apparatus of claim 8, wherein the change in communication requirements is due to a change in data rate, a change in service, a change in quality of service (QoS), or a combination thereof.

10. The device of claim 1, wherein the processor selects the configuration in response to a change of state in a connected mode.

11. The device of claim 1, wherein the processor selects the configuration in response to a transition from an idle mode to a connected mode.

12. The device of claim 1, wherein the processor selects the configuration in response to a handover from a first radio access technology to a second radio access technology.

13. A method, comprising:

selecting a configuration for communicating with a wireless device;

identifying a default configuration from a set of default configurations, each default configuration associated with a respective set of parameter values for communication;

determining a difference between the selected configuration and the default configuration if the difference exists; and

sending an identification of the default configuration and the difference to communicate the selected configuration if the difference exists.

14. The method of claim 13, wherein the determining the difference comprises determining an information element having different values in the selected configuration and the default configuration.

15. The method of claim 14, further comprising:

forming a reconfiguration message using the identification of the default configuration and the information element having a different value.

16. The method of claim 13, wherein the selecting the configuration comprises selecting the configuration in response to a change in communication requirements due to a change in data rate, a change in service, a change in quality of service (QoS), a change in state in a connected mode, a transition from an idle mode to the connected mode, a handover from a first radio access technology to a second radio access technology, or a combination thereof.

17. An apparatus, comprising:

means for selecting a configuration for communicating with a wireless device;

means for identifying a default configuration from a set of default configurations, each default configuration being associated with a respective set of parameter values for communication;

means for determining a difference between the selected configuration and the default configuration if the difference exists; and

means for sending an identification of the default configuration and the difference to communicate the selected configuration if the difference exists.

18. The apparatus of claim 17, wherein the means for determining the difference comprises

Means for determining an information element having a different value in the selected configuration and the default configuration.

19. The apparatus of claim 18, further comprising:

means for forming a reconfiguration message with the identification of the default configuration and the information element having a different value.

20. A processor-readable medium storing instructions for:

selecting a configuration for communicating with a wireless device;

identifying a default configuration from a set of default configurations, each default configuration associated with a respective set of parameter values for communication;

determining a difference between the selected configuration and the default configuration if the difference exists; and

sending an identification of the default configuration and the difference to communicate the selected configuration if the difference exists.

21. The processor-readable medium of claim 20, further storing instructions to:

determining an information element having different values in the selected configuration and the default configuration; and

forming a reconfiguration message using the identification of the default configuration and the information element having a different value.

22. An apparatus, comprising:

a memory storing a set of default configurations, each default configuration being associated with a respective set of parameter values for communication; and

a processor that receives an indication of a change in communication requirements of a wireless device operating in a connected mode, selects a default configuration from the set of default configurations based on the communication requirements, and sends the default configuration to the wireless device.

23. The method of claim 22, wherein the change in communication requirements is due to a change in state in the connected mode.

24. The apparatus of claim 22, wherein the change in communication requirements is due to a change in data rate, a change in service, a change in quality of service (QoS), or a combination thereof.

25. A method, comprising:

receiving an indication of a change in communication requirements of a wireless device operating in a connected mode;

selecting a default configuration from a set of default configurations based on the communication requirements, each default configuration being associated with a respective set of parameter values for communication; and

transmitting the default configuration to the wireless device.

26. The method of claim 25, wherein the receiving the indication of the change in communication requirements comprises:

receiving an indication of a change in communication requirements due to a change in data rate, a change in service, a change in quality of service (QoS), a change in status in the connected mode, or a combination thereof.

27. An apparatus, comprising:

means for receiving an indication of a change in communication requirements of a wireless device operating in a connected mode;

means for selecting a default configuration from a set of default configurations based on the communication requirements, each default configuration being associated with a respective set of parameter values for communication; and

means for transmitting the default configuration to the wireless device.

28. An apparatus, comprising:

a memory storing a set of default configurations, each default configuration being associated with a respective set of parameter values for communication; and

a processor that receives a message containing an identification of a default configuration, obtains the default configuration from the memory based on the identification, determines whether the message contains a difference between the default configuration and a selected configuration, and replaces parameter values of the default configuration with the difference sent in the message if the difference is contained.

29. The device of claim 28, wherein the message contains the identification and no difference, and wherein the processor uses the default configuration for communication.

30. The apparatus of claim 28, wherein the processor uses the default configuration and the difference for communication.

31. The apparatus of claim 28, wherein each default configuration is associated with a default value for a corresponding set of information elements, the default value being the set of parameter values for the default configuration.

32. The device of claim 31, wherein the processor extracts an information element from the message that contains the difference, replaces a default value of the information element in the default configuration with a value of the extracted information element, and retains the default value of the information element in the default configuration that was not sent in the message.

33. The device of claim 28, wherein the processor receives the message in response to a change in communication requirements.

34. The device of claim 28, wherein the processor receives the message in response to a change in state in connected mode.

35. The device of claim 28, wherein the processor receives the message in response to a transition from an idle mode to a connected mode.

36. The device of claim 28, wherein the processor receives the message in response to a handover from a first radio access technology to a second radio access technology.

37. A method, comprising:

receiving a message having an identification of a default configuration;

obtaining the default configuration from a set of default configurations based on the identification, wherein each default configuration is associated with a respective set of parameter values for communication;

determining whether the message includes a difference between the default configuration and a selected configuration; and

replacing parameter values of the default configuration with the differences sent in the message if the differences are included.

38. The method of claim 37, wherein said replacing parameter values of the default configuration comprises:

extracting an information element containing the difference from the message,

replacing default values of information elements in the default configuration with the extracted values of information elements, and

retaining default values for information elements in the default configuration that are not sent in the message.

39. The method of claim 37, wherein the receiving the message comprises:

receiving the message with the identification of the default configuration in response to a change in communication requirements due to a change in data rate, a change in service, a change in quality of service (QoS), a change in state in a connected mode, a transition from an idle mode to the connected mode, a handover from a first radio access technology to a second radio access technology, or a combination thereof.

40. An apparatus, comprising:

means for receiving a message having an identification of a default configuration;

means for obtaining a default configuration from a set of default configurations based on the identification, wherein each default configuration is associated with a respective set of parameter values for communication;

means for determining whether the message includes a difference between the default configuration and a selected configuration; and

means for replacing a parameter value of the default configuration with the difference sent in the message if the difference is included.

41. The apparatus of claim 40, wherein the means for replacing parameter values of the default configuration comprises:

means for extracting an information element containing the difference from the message,

means for replacing a default value of an information element in said default configuration with the value of the extracted information element, an

Means for retaining a default value for an information element in the default configuration that is not sent in the message.

42. A processor-readable medium storing instructions for performing the following operations in a wireless device:

receiving a message having an identification of a default configuration;

obtaining a default configuration from a set of default configurations based on the identification, wherein each default configuration is associated with a respective set of parameter values for communication;

determining whether the message includes a difference between the default configuration and a selected configuration; and

replacing parameter values of the default configuration with the differences sent in the message if the differences are included.

43. The processor-readable medium of claim 42 further storing instructions to:

extracting an information element containing the difference from the message;

replacing the default value of the information element in the default configuration with the value of the extracted information element; and

retaining default values for information elements in the default configuration that are not sent in the message.

44. An apparatus, comprising:

a memory storing a set of default configurations, each default configuration being associated with a respective set of parameter values for communication; and

a processor that receives a reconfiguration message in response to a change in communication requirements of a wireless device operating in a connected mode, extracts an identification of a default configuration from the reconfiguration message, obtains the default configuration from the memory based on the identification, and uses the default configuration for communication.

45. The device of claim 44, wherein the change in communication requirements is due to a change in status in the connected mode.

46. The apparatus of claim 44, wherein the change in communication requirements is due to a change in data rate, a change in service, a change in quality of service (QoS), or a combination thereof.

47. A method, comprising:

receiving a reconfiguration message in response to a change in communication requirements of a wireless device operating in a connected mode;

extracting from the reconfiguration message an identification of a default configuration, the default configuration being from a set of default configurations and each default configuration being associated with a respective set of parameter values for communication;

obtaining the default configuration from memory based on the identification; and

using the default configuration for communication.

48. An apparatus, comprising:

means for receiving a reconfiguration message in response to a change in communication requirements of a wireless device operating in a connected mode;

means for extracting from the reconfiguration message an identification of a default configuration, the default configuration being from a set of default configurations and each default configuration being associated with a respective set of parameter values for communication;

means for obtaining the default configuration from memory based on the identification; and

means for using the default configuration for communication.