RU2384948C2 - Interruption of use of frequency level convergence circuit - Google Patents

Abstract

FIELD: physics, communications.

SUBSTANCE: present invention is aimed at interrupting use of a frequency level convergence circuit which supports selection of a cell with the preferred frequency for a multiaddress service. A mobile terminal connected to the multiaddress service having the preferred frequency uses a frequency level convergence circuit for repeated cell selection. The frequency level convergence circuit supports selection of the cell on the preferred frequency level. However, use of the frequency level convergence circuit is interrupted if there is a motive.

EFFECT: potential increase in efficiency of a wireless communication system in cases when operating terminals cannot support a separate frequency.

47 cl, 12 dwg, 1 tbl

Description

FIELD OF THE INVENTION

[1] The present invention relates to cell selection in a wireless communication system and, more specifically, to discontinuing use of a frequency level convergence circuit, which favors cell selection at a preferred frequency associated with multicast service.

State of the art

[2] Recently, mobile communication systems have received significant development, however, with respect to the transfer of large amounts of information, the characteristics of mobile communication systems do not yet reach the characteristics of wired communication systems. Accordingly, technical developments are underway within the framework of IMT-2000 - a communication system that provides the transfer of large amounts of information, and standardization of this technology is actively carried out in various companies and organizations.

[3] The UMTS universal mobile telecommunication system is a third-generation mobile communication system, which was the result of the evolution of the European standard, known as the global GSM mobile communication system. The goal of the UMTS universal mobile telecommunication system is to provide high-quality mobile communications services based on the GSM core network and code division multiple access (W-CDMA) technology as a wireless communication technology.

[4] In December 1998, the European Telecommunications Standards Institute (ETSI) in Europe, the Radio Industry Association and the Communications Technology Committee (ARIB / TTC) in Japan, the U.S. Institute of Standards Institute T1 and the South Korean Telecommunications Technology Association (TTA) organized The project on cooperation on third-generation systems (3GPP) for the development of detailed specifications for the technology of the universal mobile communications system "UMTS".

[5] In order to ensure the fast and efficient technical development of the UMTS mobile communication system within the framework of the 3GPP project, five TSG groups were created to standardize the universal UMTS mobile communication system taking into account the independent nature of the network elements and their operation .

[6] Each TSG team develops, approves and monitors standard specifications within its respective field. Among these groups, the Network Radio Communications Group (TSG-RAN) is developing standards for functions, required elements and the UTRAN universal terrestrial radio access network interface, which is a new radio access network to support code division multiple access (W- CDMA) in the universal mobile communication system “UMTS”.

[7] FIG. 1 illustrates an example of a basic network structure of a conventional universal mobile communications system “UMTS”. As shown in FIG. 1, the UMTS universal mobile communication system is simplified into terminal 10 or UE user equipment, UTRAN universal terrestrial radio access network 100, and CN core network 200.

[8] The UTRAN universal terrestrial radio access network 100 includes one or more subsystems 110, 120 of the RNS radio network. Each of the subsystems 110, 120 of the radio network "RNS" contains a controller 111 of the radio network "RNC" and many base stations 112, 113 - "Node B", controlled by the controller 111 of the radio network "RNC". An RNC radio network controller 111 controls the distribution of radio resources and controls the radio resources, and also acts as an access point with respect to the core network 200.

[9] Base stations 112 "Node B" receive information sent by the physical layer of the subscriber (terminal) on the uplink, and transmit data to the subscriber on the downlink. Base stations 112, 113 act as access points to the UTRAN for the terminal.

[10] The main function of the UTRAN universal terrestrial radio access network 100 is to create and support the RAB broadband radio channel (hereinafter, the RAB radio channel) for organizing communication between the terminal and the core network 200. The core network 200 makes requirements for the RAB radio channel end-to-end QoS quality of service, and the RAB radio channel supports QoS quality of service requirements established by core network 200. Since UTRAN universal terrestrial radio access network 100 itself forms and supports the RAB radio channel, quality requirements condition yy “QoS” end-to-end connections are satisfied. The services of the RAB radio channel are divided into the services of the broadband radio interface Iu bearer and the services of the broadband radio channel. The services of the Iu broadband radio interface support the reliable transfer of user data between the boundary nodes of the UTRAN universal terrestrial radio access network 100 and the core network 200.

[11] The core network 200 includes a mobile switching center 210 "MSC" and a gateway switching center 220 mobile communications "GMSC" connected to each other to support circuit-switched services "CS", as well as node 230 "SGSN" - a serving packet switching support node in a mobile network (GPRS) (hereinafter, a serving SGSN node 230) and a GGSN node 240 — a mobile packet network switching support node (GPRS) (hereinafter, a GGSN gateway 240) ) connected to each other to support the service with packet switching "PS".

[12] The services provided to a particular terminal may be a circuit switched service “CS” or a packet switched service “PS”. For example, regular voice telephony is a CS-switched service, and Internet access through an Internet connection is considered a PS-switched service.

[13] To support circuit switched services, the RNC radio controllers 111 are connected to the MSC mobile switching center 210 of the core network 200, and the MSC mobile switching center 210 is connected to the GMSC mobile switching center 220, which manages connections to other networks.

[14] To support packet switching services, the RNC radio controllers 111 are connected to the support SGSN 230 and the GGSN gateway 240 of the core network 200. The SGSN 230 serves as a packet communication with the RNC radio controllers 111 ”, And the GGSN gateway 240 controls the connection to other packet-switched networks, such as the Internet.

[15] There are various interfaces between network components that enable communication between these components to exchange data. The interface between the RNC radio network controllers 111 and the core network 220 is defined as the Iu interface. In particular, for packet-switched networks, the interface between the RNC radio network controllers 111 and the core network 200 is defined as “Iu-PS”, and for the circuit-switched networks, the interface between the RNC radio network controllers 111 and the core network 200 is defined as “Iu -CS. "

[16] FIG. 2 shows a protocol structure of a radio communication interface between the terminal and the UTRAN universal terrestrial radio access network based on 3GPP subscriber radio standards.

[17] As shown in FIG. 2, the horizontal radio interface protocol includes a physical layer, a data link layer and a network layer, and vertically includes a user plane (U-plane) for transmitting user data, and control plane (C-plane), which serves to transmit control signals.

[18] The user plane is the area where the user’s information flow (traffic) is processed, for example, voice or IP packets, while the control plane is the area where control information is processed to interface with the network, support calls and call control, etc.

[19] The protocol layers in FIG. 2 can be divided into a first layer (L1), a second layer (L2) and a third layer (L3) based on the three lower layers of the standard Open System Interconnection (OSI) model. Each of the layers of the radio protocol is described in more detail below.

[20] The first level (L1), namely the physical layer, provides services for the transmission of information to higher layers using various radio transmission technologies. The physical layer is connected to the upstream layer, which is called the MAC access control layer, using the transport channel. Data exchange between the MAC access control layer and the physical layer is carried out through this transport channel.

[21] The second level (L2) includes a MAC access control layer, an RLC radio control layer, a Navy broadcast / multicast control level, and a PDCP packet data convergence protocol level.

[22] The medium access control layer “MAC” provides the assignment of parameters of the medium access control layer “MAC” for the distribution and redistribution of radio resources. The MAC access control layer is connected to an upstream layer called the RLC radio channel control layer via a logical channel.

[23] Depending on the type of information transmitted, various logical channels are provided. As a rule, when transmitting information to the control plane, a control channel is used. When transmitting user plane information, a traffic channel (information exchange channel) is used. The logical channel may be a shared channel or a dedicated channel, depending on whether it is a shared (multiplexed) channel. The logical channels include a dedicated information channel "DTCH", a dedicated control channel "DCCH", a common information channel "STCH", a common control channel "CCCH", a broadcast control channel "BCCH" and a paging control channel "RCCH" or a shared control channel channel "SHCCH". The BCCN broadcast control channel transmits information including data used by the terminal to access the system. The RCCN paging control channel is used by the UTRAN universal terrestrial radio access network to access the terminal.

[24] A multimedia broadcast / multicast service (“MBMS” or “MBMS service”) refers to a method for providing streaming or background services to multiple terminals using a broadband downlink dedicated multimedia broadcast / multicast service channel “MBMS” that uses at least either a broadband radio channel of multipoint communication of one subscriber with several or a broadband radio channel of direct communication. One MBMS service consists of one or more sessions, and MBMS multimedia broadcast / multicast data is transmitted to multiple terminals over the MBMS multimedia broadcast / multicast service broadband channel only during a session.

[25] According to the name, the MBMS multimedia broadcast / multicast service can be provided in broadcast mode or in multicast mode. A broadcast mode is the transmission of multimedia information to all “UEs” in the broadcast area, that is, in the area where broadcast is possible. The multicast mode is the transmission of multimedia information to a specific group of users in the field of multicast transmission, for example, in the area where multicast transmission is possible.

[26] For MBMS multimedia broadcast / multicast services, additional traffic and control channels exist. For example, the channel "MSSN" (multi-point control channel of the multimedia broadcast / multicast service "MBMS") is used to transmit control information of the multimedia broadcast / multicast service "MBMS", while the channel "MTSN" (multi-point control channel of the graph of the multimedia broadcast / multicast service "MBMS) ") Is used for data transmission services multimedia broadcast / multicast service" MBMS ".

[27] The various existing logical channels are listed below:

[28] The MAC access control layer is connected to the physical layer by transport channels and, in accordance with the type of transport channel being controlled, is divided into the broadcast media access control sublayer - “MAC-b” (hereinafter, the “MAC-” broadcast channel control sublayer b "), the sub-level of access control for the medium of the dedicated channel -" MAC-d "(hereinafter, the sub-level of control of the access of the dedicated channel" MAC-d "), the sub-level of access control of the medium of the shared and shared channels -" MAC-c / sh "( further sublevel control of the shared and shared channels “MAC-c / sh”) and the sub-level of access control to the shared channel environment - “MAC-hs” (hereinafter, the sub-level of control of the shared channel “MAC-hs”).

[29] The MAC-b broadcast channel control sublayer controls the BCH broadcast channel, which is a transport channel that broadcasts system information. The MAC-d dedicated channel control sublayer controls the dedicated DCH channel, which is a dedicated transport channel for a particular terminal. Accordingly, the UTRAN dedicated terrestrial radio access network dedicated MAC-d control sublayer is located in the serving SRNC radio network controller that controls the corresponding terminal, and in addition, one dedicated MAC-d dedicated control sublayer is present in each from the terminals "UE".

[30] The MAC-c / sh shared and shared control sublayer controls a shared transport channel, such as a direct access channel FACH or a downlink shared channel DSCH that is shared by several terminals, or an uplink subscriber radio channel "RACH" (random access channel). In the UTRAN universal terrestrial radio access network, the MAC-c / sh shared and shared channel control sublayer is located in the CRNC radio network control controller. Since the MAC-c / sh shared and shared channel control sublayer controls the channel that is shared by all terminals in the cell, each cell area has a single MAC-c / sh shared and shared channel control sublayer. In addition, one MAC-c / sh shared and shared channel control sublayer is present in each of the UEs. FIG. 3 shows a possible mapping between logical channels and transport channels for a “UE” terminal. FIG. 4 shows a possible mapping between logical channels and transport channels for the UTRAN universal terrestrial radio access network.

[31] The “RLC” radio channel control layer supports reliable data transmission and performs the functions of segmentation and congatenation of a plurality of service data blocks of the radio channel control layer, “RLC SDU”, transmitted from an upstream layer. When the RLC radio channel control level receives the service data blocks of the RLC SDU radio channel control level from a higher level, the RLC radio channel control level adjusts the size of each service data block of the RLC SDU radio channel control level accordingly taking into account processing performance and then creates certain data blocks with header information added to them. Then, the created data blocks, called Protocol Data Units - “PDUs”, are transferred to the MAC access control layer through the logical channel. The radio channel control level “RLC” includes a buffer of the radio channel control level “RLC” for storing service data units of the radio channel control level - “RLC SDU” and / or protocol data units of the radio channel control level - “RLC PDU”.

[32] The Navy broadcast / multicast control layer plans to transmit broadcast messages for a cell (hereinafter referred to as "CB messages") received from the core network and broadcasts "CB messages" to UEs located in specific cell (s). The Navy Broadcast / Multicast Control Layer generates a Navy Broadcast / Multicast Control message with the addition of information such as a message identifier, serial number, coding scheme, and transmits a level message to the CB message received from the upstream layer “Naval Forces” to the RLC radio channel control level. Messages of the “Naval Forces” level are transmitted from the “RLC” radio channel control level to the “MAC” medium access control level via a logical channel, that is, through a common STSN traffic channel. The logical channel "STSN" is displayed on the transport channel, that is, the direct access channel "FACH", which is displayed on the physical channel, that is, the auxiliary common physical control channel "S-CCPCH".

[33] The packet data convergence protocol layer “PDCP” is an upper layer for the “RLC” radio link control layer and allows efficient data transmission using a network protocol (such as “IPv4” or “IPv6”) over a relatively narrow bandwidth radio interface. To achieve this, the packet data convergence protocol layer “PDCP” has the function of reducing the necessary control information used in the wired network, a function of this type being called header compression.

[34] The Radio Resource Control (RRC) layer is located at the very bottom of the L3 layer. The radio resource control level “RRC” is defined only in the control plane; it manages the logical channels, transport channels and physical channels with respect to tuning, reconfiguring and releasing or canceling the RB radio channels. Radio channel service refers to the service provided by the second L2 layer for data transmission between the terminal and the UTRAN terrestrial radio access network. In general, setting up a radio channel (RB) refers to regulating protocol levels and channel characteristics needed to deliver specific services, as well as setting appropriate parameters and operating methods.

[35] The RLC radio control layer may belong to a user plane or a control plane depending on the type of level connected to the upper layer for the RLC radio control layer. That is, if the RLC radio control layer receives data from the RRC radio resource control layer, the RLC radio control layer belongs to the control plane. Otherwise, the RLC radio control layer belongs to the user plane.

[36] In principle, display options between broadband radio channels and transport channels are in fact not always possible. “UE” / “UTRAN” determines the possible mappings depending on the status of the “UE” terminal and the procedure performed by the “UE” / “UTRAN”. Various states and modes are explained in detail below.

[37] Different transport channels are mapped to different physical channels. For example, the transport channel "RACH" - an uplink channel for subscriber radio communications (random access channel), is mapped to some physical subscriber channel "PRACH", a dedicated channel "DCH" can be mapped to a physical dedicated channel "DPCH", a direct access channel "FACH" and the “PCN” paging channel can be mapped to the “S-CCPCH” channel - an auxiliary common physical control channel, the downlink shared channel “DSCH” is mapped to the physical downlink shared channel “PDSCH”, etc. The configuration of the physical channels is determined by the exchange of signals of the radio resource control levels "RRC" between the radio network controller "RNC" and the terminal "UE".

[38] The operation mode of the radio resource control level “RRC” describes whether there is a logical connection between the radio resource control level “RRC” of the terminal and the radio resource control level “RRC” of the universal terrestrial radio access network “UTRAN”. If the connection exists, it is considered that the terminal is in the "RRC connection" mode. If there is no connection, the terminal is considered to be in standby (inactivity) mode. Since there is an “RRC connection” for terminals in a mode with connected RRC radio resource control levels, the UTRAN can determine the location of a specific terminal to the cell accuracy. For example, the UTRAN universal terrestrial radio access network can determine the cell or group of cells where the terminal with the connected RRC radio resource control levels is located and which physical channel the UE listens on. Thus, the terminal can be effectively controlled.

[39] In contrast, the UTRAN cannot detect the presence of a standby terminal. The availability of standby terminals can only be determined by the core network. Specifically, the core network can detect the presence of standby terminals only within an area larger than a cell, for example, in a settlement or routing area. Thus, the availability of standby terminals is determined in large areas. In order to receive information from mobile communication services, such as speech or data, the terminal must move from standby mode or switch to the “RRC connection” mode. Possible transitions between modes and states are shown in FIG. 5.

[40] A UE in RRC Connection mode. may be in various states, for example, state "CELL_FACH", state "CELL_PCH", state "CELL_DCH" or state "URA_RCN". Depending on its state, the UE listens on various channels. For example, a terminal “UE” in the “CELL_DCH” state will try to listen (among others) for transport channels of the dedicated channel type “DCH”, which contains a dedicated graphics channel - “DTCH” and a dedicated control channel - “DCCH”, and which can be mapped to a specific physical dedicated channel "DPCH". The terminal "UE" in the state "CELL_FACH" will listen to several transport channels direct access "FACH", mapped to a specific auxiliary common physical control channel "S-SSRSN. Terminal 2 “UE” in the “CELL_PCH” state will listen on the “PICH” channel and the “PCH” channel, which are mapped to a specific auxiliary common physical control channel “S-CCPCH”.

[41] The UE also performs various actions depending on its state. For example, based on various conditions, the UE terminal in the CELL_FACH state starts the CELL Update cell update procedure each time the UE terminal moves from the coverage area of one cell to the coverage area of another cell. The UE terminal starts the CELL Update cell update procedure by sending a message about the Cell Update cell update to the Node-B base station to indicate that it has changed its location. Then the UE terminal starts listening to the direct channel “FACH” access. This procedure is also used when the terminal goes from any state to the “CELL_FACH” state and does not have a temporary radio network identifier of the “C-RNTI” cell (s), for example, when the terminal goes to the specified state from the state "CELL_PCH" or state " CELL_DCH ", or when the terminal is in the CELL_PCH state, is outside the cell range.

[42] In the CELL_DCH state, dedicated resources are provided to the UE, and the terminal can also use shared radio resources. This gives the terminal the ability to have a high data rate and efficiently exchange data. However, radio resources are limited. The UTRAN universal terrestrial radio access network has the task of distributing radio resources among network subscribers so that these resources are used efficiently and to ensure that subscribers receive the required quality of service.

[43] The UE in the CELL_FACH state does not have allocated assigned radio resources and can only communicate with the UTRAN over the shared radio channels. Thus, the terminal consumes a small amount of radio resources. However, the available data rate is too limited. In addition, the terminal must constantly monitor the shared channels. Thus, the battery consumption of the terminal increases if the terminal does not transmit.

[44] The “UE” terminal in the “CELL_PCH” / “URA_PCH” states can only monitor the paging channel in specially defined cases and thus minimizes battery consumption. However, if the network needs to access the terminal, it must first indicate this intention during the paging session. After that, the network can access the terminal, but only if the terminal responded to the page request. In the future, the terminal can gain access to the network only after performing the Cell Update cell update procedure, which introduces additional time losses when the terminal wants to send data to the UTRAN universal terrestrial radio access network.

[45] The main system information is received through the BCCN broadcast control logical channel mapped to the R-SSRSN primary physical control channel. Specific blocks of system information can be transmitted on the direct access channel "FACH". When transmitting system information via the direct access channel “FACH”, the terminal receives the configuration of the direct access channel “FACH” either through the BCCH broadcast control channel received on the R-SSRCN primary physical control channel or through a dedicated channel. Transmission on the primary common physical control channel "R-SSRSN" is carried out using the same scrambling code that is used in the channel "P-CPICH" (primary common pilot channel), this code is the main (primary) cell scrambling code.

[46] Each channel uses extensible code, as is usually done in WCDMA code division multiple access systems. Each code is characterized by its coefficient of expansion "SF", which corresponds to the capacity of the code. For a given expansion coefficient, the number of orthogonal codes is equal to the code length. For each expansion coefficient, a predetermined set of orthogonal codes, as defined in the UMTS universal mobile telecommunication system, is numbered from “0” to “SF-1”. Each code is thus identified by assigning it a bit depth (i.e., an expansion coefficient) and a code number. Extensible code. used by the R-SSRSN primary physical control channel, always has a fixed expansion coefficient of 256, and the code number is 1. The terminal learns about the primary scrambling code either from the information transmitted by the network along with the system information of adjacent cells that the terminal read or from messages received by the terminal via the dedicated DCCH control channel, or by searching for the primary common pilot channel P-CPICH, which are transmitted using the fixed spreading factor SF = 256 and the number extensible code equal to "0", and which conveys a specific set of characters.

[47] The system information contains information about adjacent cells, about the configuration of the random access transport channels “RACH” and direct access “FACH”, and about the configuration of the multicast control channel “MCHN”, which is a channel dedicated to the MBMS multimedia broadcast / multicast service ". After the terminal selects a cell (in the CELL_FACH, CELL_PCH, or URA_PCH states), the terminal checks the validity of the received system information.

[48] System information is organized into SIB system information blocks, MIB basic information blocks, and planning blocks. The basic information block “MIB” is sent quite often and provides information on the synchronization of planning blocks and various blocks of system information “SIB”. For “SIB” system information blocks linked to a marker value, the “MIB” block / blocks of basic information also contains information about the latest version of a part of the “SIB” system information blocks. SIB system information blocks that are not tied to marker values are tied to an expiration timer (pointer). SIB system information blocks tied to an expiration timer (pointer) become invalid and require re-reading if the last read time of the SIB system information block is longer than the value indicated by the expiration timer. SIB system information blocks associated with marker values are valid if they have a marker value similar to the marker value sent in the MIB basic information blocks. Each block has a limit zone, it can be, for example, a cell, public land mobile network - “PLMN” or its equivalent, which shows in which cell the system information block “SIB” is valid. The “SIB” system information block, having a “Cell” size coverage area, is valid only for the cell in which it was read. Block / blocks of system information “SIB” having a coverage area of size “PLMN” is valid in the entire public land mobile communication network. The SIB system information unit having a coverage area of the size of the “PLMN equivalent” is valid in all of this PLMN public land mobile network and in the equivalent of this public land mobile network.

[49] According to the 3GPP system standard, the LJE terminal, in the CELL_PCN, URA_RCN, CELL_FACH or standby state, must constantly attempt to select / reselect a suitable cell (for non-emergency calls) or acceptable cells (for emergency calls). In standby mode, when the UE has selected a cell, the UE is usually called a “call waiting” in the cell. In “RRC connection” mode, when the “UE” terminal is in the “CELL_PCH”, “URA_PCH” or “CELL_FACH” state, the “UE” terminal is usually called the “selector” cell.

[50] In order to facilitate cell reselection, the network transmits lists of neighboring cells as part of the system information. Lists of neighboring cells identify available cells whose characteristics the UE should measure and compare with the cell that the UE has currently selected, or with the cell in which the UE is waiting for a call. Available cells can operate at the same frequency, at different frequencies, or based on other RAT radio access technologies, such as GSM. As a candidate for selecting a cell, a list of cells is used, as well as random cells that the UE detects on its own.

[51] One element of the cell selection / reselection process is based on quality measurements of various cells that are on the list of neighboring cells that are candidates for cell selection. A cell may or may not belong to the hierarchical structure of cells - “HCS”. This is defined in the system information of a given cell. In the case of a hierarchical cell structure, each cell has a given priority. The cell selection procedure varies depending on whether or not the cell is part of the hierarchical structure of the cells.

[52] In order to decide which of the candidate cells to select, the UE measures the quality of service in neighboring cells. The “UE” terminal uses the above formula to set the ranking criterion - “R” for all candidate cells. The formula is based on measurements of channel quality — the common pilot channel “CPIH” / primary common physical control channel “R-SSRSN” and on the information received as part of the system information of the candidate cell. The criterion "R" is equal to a positive or negative value. The value of "R" can be calculated as follows, where "R _S " is the value of the ranking criterion for the serving cell, "R _n " is the value of the ranking criterion for neighboring cells:

R _S = Q _{meas, s} + Qhyst _s + Qoffmbms R _n = Q _{meas, n} + Qoffset _{s, n} + Qoffmbms-TO _n * (1-L _n ) Ton = TEMP_OFFSETn * W (PENALTY_TIME _n -T _n ) L _n = 0 if HCS_PRIO _n = HCS_PRIO _s L _n = 1 if HCS_PRIO _n <> HCS_PRIO _s W (x) = 0 for x <0 W (x) = 1 for x> = 0

[53] The reported QoS value - “Qoffmbms” refers only to cells (serving or adjacent) that belong to the preferred frequency for the MBMS multimedia broadcast / multicast service (that is, where a frequency convergence scheme is used). “Qmeas” gives the quality value of the received signal obtained from the average “Ec / No” of the common pilot channel “CPIH”, or from the power of the received code signal “RSCP” of the common pilot channel “CPICH” for the cells in the “FDD” mode - (duplex communication with frequency division of channels), from the average power of the received RSCP code signal of the primary common physical control channel R-CCRSN for cells in TDD mode - (duplex communication with time division) and from the average power level of the received signal for GSM cells . For cells in the "FDD" mode, the measurement that is used to obtain the quality value is indicated in the system information.

[54] The parameters “Qhyst”, “Qoffsets, n”, “Qoffmbms”, “TEMP_OFFSET” and “PENALTY_TIME” are indicated in the system information. For each cell, the timer “T” starts and stops, depending on the quality of the radio communication in the cell.

[55] If the hierarchical cell structure of “HCS” is used, then the criterion “H” is defined (hierarchical). Criterion “H” has a positive or negative value and is calculated based on the information transmitted as part of the system information and on the measurements from the common pilot channel “CPIH” / primary common physical control channel “R-SSRSN” of the candidate cell. A cell in a hierarchical cell structure can have different priorities. Criterion "H" is calculated in accordance with the following formula:

H _s = Q _{meas, s} -Qbcs _s H _n = Q _{meas, n} -Qhcs _n -TO _n * L _n

[56] “TO _n ” and “LN”, “Q _{meas, s} ” and “Q _{meas, n} ” are defined similarly to the above definition. The purpose of such a cellular structure is to reach users of one area with low mobility, as well as users with high mobility. To optimize capacity, small cells are preferred so that the number of cells is as large as possible. Accordingly, this makes it possible to have the maximum number of users in this area.

[57] However, for fast-moving users, it is preferable to have large cells, which will reduce the number of transitions between cells when moving the terminal "UE". To distinguish between large cells and small cells, the cell is assigned different priorities. The UE terminal tries to select the cells with the highest priority. This usually corresponds to a small cell, except when the UE is moving fast. The 3GPP standard uses the “H” criterion to take priority into account. However, when the “UE” terminal detects that it is moving fast (that is, having detected frequent completion of the cell reselection procedure by the “UE” terminal), the “UE” terminal stops using the “H” criterion and no longer takes into account the cell priority. It is further believed that the UE is in a “high mobility state”.

[58] The selection criterion “S” checks whether the obtained quality of the candidate cell is sufficient. To do this, the “UE” terminal measures the “Q _qualmeas ” value - the measured channel quality, which expresses “E _c / N _o ” of the common pilot channel “CPICH” of the candidate cell (only for cells in the “FDD” mode - duplex communication with frequency division of channels). In addition, the terminal measures the Q _rxlevmeas value, which estimates the power of the received RSCP code signal of the common pilot channel CPICH of the candidate cell for the cells in FDD mode and the primary common physical control channel P-SSRC of the candidate cell for cells in TDD mode - duplex communication with time division. The UE terminal uses these values together with the information received as part of the system information of the candidate cell in the algorithm to calculate the S value. If the “S” value is greater than 0, the “S” criterion for selecting a cell is satisfied. Otherwise, it fails.

[59] In addition to the above criteria “R”, “H” and “S”, the selection of a cell by the terminal “UE” may be determined by other criteria. Information about these criteria is given to the UE terminal in the form of "cell access restrictions", which are transmitted in broadcast mode as part of system information.

[60] One of the typical examples of restricting access to a cell may be “closed cells”. Each UE uses a parameter called an Access Class, which gives the UE some kind of priority. There are access groups in the range from 0 to 15. For each of the access groups in the system information, it can be indicated whether the cell is closed or not. A cell can also be closed altogether.

[61] Another typical pattern of restricting access to a cell is when the cell is “reserved for use by the operator”. The system information may indicate whether or not a cell is reserved for use by the operator. Depending on whether the group of the UE terminal is operator or not, and whether the UE makes an emergency call or not, the UE can select a cell that is reserved or not reserved for use by the operator during the re-selection process.

[62] Further, access to the cell may be limited since it is “reserved for future expansion”. The system information may indicate whether or not a cell is reserved for future expansion.

[63] Cell access may be limited due to the public land mobile network “PLMN”. Each cell belongs to one or more PLMN public land mobile networks. When the UE is turned on, it selects the PLMN public land mobile network, and can only change the PLMN public land mobile network using special signal exchange. When the UE makes a cell selection / reselection, it checks to see if the selected public land mobile network “PLMN” of the network “PLMN” of the cell. The UE may use the list of “equivalent public land mobile networks" PLMN ", where the" equivalent PLMN "is considered identical to the selected public land mobile networks" PLMN. "A terminal" UE "that does not attempt to perform an emergency the call may select / reselect such cells that belong to the selected PLMN or the PLMN equivalent to the selected PLMN.

[64] In addition, a “cell reselection indicator within the frequency” is transmitted as part of the system information, which prohibits the UE from selecting a cell if the cell that the UE has selected is closed to reselect another cell on the same frequency.

[65] Accordingly, the aforementioned “cell access restriction” attributes limit the number of candidate cells that the UE may consider when selecting / reselecting a cell. Figure 6 illustrates the decision-making process when reselecting cells.

[66] The main objective of the RNC radio network controller is radio resource management (RRM). To optimize the use of available radio resources, the standard of the universal mobile telecommunication system “UMTS” provides for various states of the radio resource control level, further, “RRC states”, different transport channels and different physical channels.

[67] The main method of distributing RRM radio resources is the transition of the "RRC state" between the states "CELL_FACH", "CELL_DCH". “CELL_PCH” and “URA_PCH”. Together with these states, when communication is possible at different frequencies, the RNC radio network controller in general can control the number of UEs using this frequency. However, in accordance with the above, in the “CELL_FACH”, “CELL_PCH” and “URA_PCH” states, the “UE” terminal can initiate, based on measurements and various rules, the transition from a cell at a given frequency to a cell at a different frequency. The transition is based either on the usual measurement and cell selection / reselection rules, or on the use of a convergence scheme of frequency levels.

[68] When the UE transitions from the CELL_DCH state to another state, the UE selects a cell to wait for a call or to connect. In general, the UE terminal considers cells at all frequencies, except when the RNC radio network controller indicates the preferred frequency in the IE information element, “Frequency Info”. In this case, the UE preferably selects a cell at a preferred frequency if a suitable cell at a preferred frequency exists.

[69] When the “UE” terminal is in the “CELL_FACH” state, the “RNC” radio network controller may recommend that the “UE” terminal select a cell on a different frequency as the preferred frequency by transmitting a message containing the “IE” information element to the “UE” terminal ! - "Frequency Info". Then, the UE will attempt to select a cell at a preferred frequency.

[70] The 3GPP system provides an MBMS multimedia broadcast / multicast service. The TSG SA technical group - (aspect of the system and services) of the 3GPP project defines the various system elements and their functions necessary to support the MBMS multimedia broadcast / multicast services. The cell broadcast service within the framework of traditional technology is limited to the service where short text messages are broadcast in a particular area. However, the MBMS multimedia broadcast / multicast service is a more advanced service, which provides multicast multimedia information to the UE terminals, which have become subscribers of the corresponding service in addition to multimedia broadcasting.

[71] The MBMS multimedia broadcast / multicast service is provided only in a downlink and is a streaming or background service provided to multiple terminals using a shared or dedicated downlink. The provision of multimedia broadcast / multicast services "MBMS" occurs in the broadcast or multicast mode. The MBMS multimedia broadcast / multicast service broadcast mode transmits multimedia information to each user located in the multicast broadcast area, while the MBMS multicast multicast / multicast service broadcast mode transmits multimedia information to a specific group of users. located in the multicast area. A broadcast area denotes an area where a broadcast service is provided, and a multicast area denotes an area where a multicast service is provided.

[72] FIG. 7 shows a process for providing a specific MBMS multimedia broadcast / multicast service using a multicast mode. The procedure can be divided into two types of actions - transparent and opaque for the universal terrestrial radio access network “UTRAN”, the process of providing the multimedia broadcast / multicast service “MBMS” is shown.

[73] Transparent actions are described as follows. A user who is about to receive the MBMS multimedia broadcast / multicast service must first become a subscriber in order to be able to receive the MBMS multimedia broadcast / multicast service, receive information about the MBMS multimedia broadcast / multicast service, and join to use the specific a set of services multimedia broadcast / multicast service "MBMS". A service announcement provides the terminal with a list of services provided and other related information. Then the user can join the use of these services. By this connection, the user indicates that he is going to receive information related to the services of which the user has become a subscriber, and is included in the group of users of the multicast service. When a user loses interest in a given MBMS multimedia broadcast / multicast service, he leaves the use of this service, that is, leaves the group of users of the multicast service. These actions can be taken using any means of communication, that is, these actions can be taken using SMS (short messages) or the Internet. These actions do not have to be performed using the UMTS universal mobile telecommunications system.

[74] In order to receive a service for which a user is a member of a multicast group, the following actions are performed. Opaque to the UTRAN universal terrestrial radio access network. The Serving Node “SGSN” informs the radio network controller “RNC” of the beginning of the session. Then, the radio network controller "RNC" notifies the terminal "UE" of the multicast group that the provision of this service has begun to initiate the reception of this service. After the necessary actions for the “UE” terminal are transmitted in broadcast mode and, as a result, the broadband multipoint radio channels of communication of one subscriber with several for this service are configured, the transmission of information begins. When the session is terminated, the serving SGSN informs the radio network controller “RNC” of the termination of the session. The RNC radio network controller, in turn, initiates a session termination. Service transfer from the “SGSN” serving node means for the “RNC” radio network controller the provision of a broadband radio channel service for transmitting MBMS multimedia broadcast / multicast service data.

[75] After the notification procedure between the “UE” terminal, the “RNC” radio network controller and the “SGSN” serving node, other procedures can be initiated to ensure data transfer, for example, establishing an “RRC connection”, establishing a connection in the packet switching area “PS ”, Convergence of frequency levels and counting.

[76] The reception of the MBMS multimedia broadcast / multicast service can be performed in parallel with the reception of other services, for example, voice or video communications, in the field of CS channel switching (CS domain), SMS transmission, in the CS channel switching area ”Or“ PS ”packet switching area (PS domain), data transmission in the PS packet switching area or any signals associated with the UTRAN universal terrestrial radio access network,“ PS ”packet switching area or“ CS ”channel switching area.

[77] In contrast to the multicast service, for broadcast, as shown in FIG. 7, only the announcement of the service should be transparently made. Neither subscription nor joining the use of the service is required. Then the actions transparent to the RNC radio network controller are the same as for multicast services.

[78] FIG. 9 shows a typical sequence of operations from the UTRAN. As shown in the drawing, the service node "SGSN" informs the radio network controller "RNC" about the beginning of the communication session (step 1). After that, the “RNC” radio network controller can perform a counting procedure, which causes some “UE” terminals to connect to the packet switching area - “PS connection” (step 2). Therefore, the establishment of an “RRC connection” for the “UE” terminals is initiated. This allows the RNC radio network controller to estimate the number of UE terminals in this cell who are interested in the service. When the UE has established a PS connection, the serving SGSN initiates the Iu interface connection procedure, which provides the RNC radio network controller with a list of multicast services to which the UE has joined.

[79] For terminals "UE2, established an" RRC connection ", interested in this service multimedia broadcast / multicast service" MBMS ", but not connected to the packet switching area" PS ", the radio network controller" RNC "transmits to the terminals" UE " A special message that prompts them to establish a “PS connection” (step 3). When the UE has established a PS connection, the serving SGSN initiates an Iu interface connection procedure, which provides the RNC with a list of multicast services to which the UE has joined. For UE terminals that are not in the CELL_DCH state, the frequency level convergence scheme allows the RNC radio network controller to prompt the UE terminals to change the frequency they are listening to (step 4).

[80] Depending on the radio resource distribution scheme “RRM,” the radio network controller “RNC” creates broadband multipoint radio channels (point-to-point-point - “PtM”) or direct-link radio channels (point-to-point - “PtP”) to provide multimedia broadcast / MBMS multicast service (actions 5a or 5b). The radio network controller "RNC" delivers the data received from the serving node "SGSN" to the terminals "UE", which are members of the multicast user group. After data transfer, the serving SGSN node informs the RNC radio network controller about the end of the session (step 6). Then, the “RNC” radio network controller releases the “PtP” direct-link radio channel or the “PtM” multipoint radio channel used to transmit the MBMS multimedia broadcast / multicast service (steps 7a or 7b).

[81] Typically, for “UE” terminals in “RRC connection” mode, there are two possibilities. The terminal “UE” either has an established connection with the packet switching area “PS” (РММ-connection mode), or does not have an established connection with the packet switching area “PS” (РММ-standby (inactivity) mode). When there is no established connection with the packet switching area “PS”, the terminal “UE” typically has a connection with the channel switching area “CS”. In other cases, the UE is not in the RRC connection mode.

[82] Two additional control channels have been introduced for the MBMS multimedia broadcast / multicast service. This channel "MSSN" (multi-point control channel multimedia broadcast / multicast service "MBMS"), hereinafter multimedia control channel "MSSN", and channel "MICH" (channel indicator notification multimedia broadcast / multicast service), hereinafter multimedia channel notification indicator "MICH ". As previously explained, the MCCH multimedia control channel is mapped to the FACH direct access channel. The multimedia channel of the notification indicator “MICH” is a new physical channel used to notify users of the need to read the multimedia control channel “MCCH”. The multimedia channel of the MICH notification indicator is intended to allow the user to execute the DRX discontinuous reception scheme. The intermittent reception scheme allows users to reduce the battery consumption of the terminal and at the same time allows them to be aware of any service for which a communication session has been started. The multimedia channel of the notification indicator “MICH” can be used to inform the user about a change in the convergence frequency, about a configuration change of the broadband multipoint radio channel “PtM”, about the switching between the multipoint radio channel “PtM” and the broadband direct communication channel “PtP”, which is necessary for reading multimedia control channel "MSSN"

[83] The multimedia control channel "MSSN" periodically transmits information about existing services, the configuration of the multi-point traffic channel of multimedia broadcast / multicast service "MBMS" (hereinafter, the multi-point channel of multimedia traffic "MTSN"), frequency convergence data, etc. . The user reads the information provided by the multimedia control channel "MSSN" in order to obtain the services to which he is subscribed, based on various starting schemes. For example, the terminal “UE” can be activated after selecting / reselecting a cell, when the terminal receives a notification about this service on the multimedia channel of the notification indicator “MICH”, or when the terminal receives a notification on the dedicated control channel “DCCH”. The configuration of the multimedia control channel "MSSN" is transmitted in the broadcast mode as part of the system information. The configuration of the multimedia channel of the MICH notification indicator (that is, an extensible code, a scrambling code, an expansion coefficient, and other information) is either fixed in the standard or is given as part of the system information.

[84] The UMTS universal mobile telecommunication system standard makes it possible to use various frequency ranges for data transmission. The frequency range in the UMTS universal mobile telecommunications system is usually indicated by “UARFCN” (the total number of radio frequencies of the universal terrestrial radio access network channel), which determines the frequency range used. This public land mobile communications network “PLMN” may use different frequencies.

[85] When the network uses different frequencies, the UE in this area selects one or more frequencies in accordance with the quality measured at that frequency. The UE may also select a frequency in accordance with other parameters transmitted as part of the system information, as explained above. To adjust the load at different frequencies, the UE terminals are distributed at different frequencies. If the MBMS multimedia broadcast / multicast service is then transmitted over the PtM broadband multipoint radio channel to reach the UE terminals at all frequencies, the transmission must be performed at all frequencies.

[86] To increase the efficiency, it is desirable that the data transfer is carried out on only one frequency, and that all UE terminals interested in this service re-select a cell on this frequency. Accordingly, such a function is called “frequency convergence”. The frequency level to which the UE must transition is called the “PFL”, the preferred frequency level. As shown in FIG. 9, a typical MBMS multimedia broadcast / multicast service session includes a “frequency convergence” period (step 4).

[87] When a frequency convergence process is used for a given service, information regarding the preferred frequency for each service is transmitted in messages either via the MCCN multimedia control channel or as part of system information. To initiate a transition to a different frequency, there are various possibilities. One of the possibilities is to encourage the UE terminal to select a cell at a preferred frequency and prohibit all cells at other frequencies from participating in cell selection / reselection.

[88] Another possibility is to change the cell reselection requirements. This can be done by adding an offset to the “R” criterion, the “S” criterion, or the “H” criterion in one of the formulas needed to determine whether to select a cell. An offset can be added for cells at a preferred frequency, or for all cells at frequencies other than the preferred. Other possibilities may be used to cause the UE to reselect a preferred frequency.

[89] In a hierarchical cell structure, the UE preferably re-selects the cell with the highest priority. If a frequency convergence scheme is used, it is understood that the UE should be allowed to select a cell at a preferred frequency, regardless of the priority of the preferred frequency. Accordingly, the use of a frequency convergence scheme may imply that the hierarchical cell structure should no longer be used.

[90] The physical subscriber channel “PRACH” is an uplink communication channel shared by various “UEs”. When the UE is about to transmit data on the uplink physical subscriber channel PRACH, there is a special mechanism to prevent the simultaneous transmission of data by the various UEs. This mechanism is called “collision avoidance” and is implemented in the universal mobile telecommunication system “UMTS” based on the segmented system “Aloha”. Figure 10 describes the transmission of a message on a physical subscriber channel "PRACH".

[91] Prior to transmitting via the physical subscriber channel “PRACH”, the terminal “UE” transmits preliminary information to the base station “Node B”. The preliminary information contains a code (signature) that the UE selects randomly among the available signatures and transmits via a special physical channel called the “RACH” subchannel. The UE terminal repeats this transmission several times until it receives a positive or negative confirmation indicator or until it exceeds this number of retransmissions. The base station "Node B" listens on all subchannels and tries to detect the presented signatures transmitted by the terminals "UE" who want to access the channel. When the base station “Node B” has accepted the signature, it confirms reception on the special physical channel of the access indication “AICH” by transmitting a code that indicates the terminal “UE” whether or not the terminal “UE” is allowed access to the physical channel of the subscriber communication “PRACH”. Accordingly, the simultaneous transmission by several terminals "UE" on the physical channel of subscriber communication "PRACH" is prevented.

[92] When the terminal UE receives a message about the lack of acknowledgment of receipt of "NACK", or when the terminal "UE" does not receive any message confirming the receipt of "ACK" or the absence of confirmation of receipt of "NACK" on the access indication channel "AICH", the UE determines whether it is allowed to restart the collision avoidance process. If another collision avoidance process is allowed according to a fixed algorithm, the UE determines the wait time before the start of the next collision avoidance process. When the UE terminal receives an ACK acknowledgment after the collision avoidance process, that is, when the UE terminal is granted access to the physical PRACH subscriber link, the UE terminal transmits a set of blocks through the physical subscriber channel PRACH (data).

[93] In accordance with the above, the frequency convergence scheme optimizes the use of radio resources by concentrating all “UE” terminals interested in a given service at a given frequency. As a result, some UEs may select a cell at a preferred frequency because they are subscribers of this MBMS multimedia broadcast / multicast service, even when UEs do not have to select a cell at a preferred frequency if they have not joined the service MBMS multimedia broadcast / multicast service.

[94] A “UE” terminal selecting a cell on a preferred frequency of an MBMS multimedia broadcast / multicast service for receiving an MBMS multimedia broadcast / multicast service potentially has a poor quality of service. This is because potentially many UEs will select a cell or cells of a preferred frequency to receive an MBMS multimedia broadcast / multicast service at a preferred frequency. Therefore, the loading of a cell or cells at this frequency increases. In addition, the radio quality of the selected cell at a preferred frequency may be worse than the radio quality at a different frequency.

[95] When the UE is about to make a call or transmit data on the uplink, depending on the state / mode in which the UE is located, the UE needs to perform various actions in accordance with the current standard, as shown in Table 1.

[96] Table 1 New challenge Data transfer (control plane or user plane) Standby (Sleep) Transmission on the RACH channel of the message "RRC Connection Request" Transmission on the RACH channel of the message "RRC Connection Request" Connection Mode /
"CELL_PCH" Transmission of the "Cell Update" message on the RACH channel Transmission of the "Cell Update" message on the RACH channel Connection Mode /
"URA_PCH" Transmission on the channel "RACH! Cell Update messages Transmission of the "Cell Update" message on the RACH channel Connection Mode /
CELL_FACH Transmission of the “Initial Direct Transfer” message via the “RACH” channel Transmission on the RACH channel of data / or message "measurement report" Connection Mode / CELL_DCH Transmission on a dedicated transport channel of the message "Initial Direct Transfer" Data transmission on a dedicated transport channel

[97] In accordance with the above, a UE using a frequency convergence scheme because it has joined the MBMS multimedia broadcast / multicast service will potentially encounter difficulties in transmitting data on a physical subscriber channel “PRACH” due to congestion cell or poor quality radio. Thus, to overcome these difficulties, a special mechanism is needed.

[98] The frequency convergence mechanism may also conflict with the preferred frequency information transmitted by the RNC radio network controller when switching from the CELL_DCH state to the CELL_FACH state, or when the RNC radio network controller indicates to the UE terminal located in the CELL_FACH state, re-select a cell at a given frequency. Accordingly, the efficiency of the system is potentially reduced, since the current UEs cannot support a single frequency.

SUMMARY OF THE INVENTION

Technical solution

[99] The present invention seeks to interrupt the use of frequency level convergence schemes, which favors cell selection at a preferred frequency associated with a multicast service.

[100] Additional features and advantages of the invention will be presented in the description below, and in part will become apparent to those skilled in the art from the description or may be learned during the practice of the invention. The objectives and other advantages of the present invention can be realized and achieved through the structure specifically discussed in the description and claims, as well as in the accompanying drawings.

[101] To solve these problems and achieve other advantages, as well as in accordance with the purpose of the present invention, which is disclosed and described in detail in this document, the present invention is embodied in a method for selecting a cell by a mobile terminal in a wireless communication system, a method that includes joining a multicast service having a preferred frequency, using a frequency level convergence scheme to select a cell, where frequency level convergence schemes support cell selection at preferred natural frequency, and interruption of the use of the scheme of convergence of frequency levels upon the occurrence of some motive reason. Preferably, the multicast is an MBMS multimedia broadcast / multicast service.

[102] In one aspect of the invention, the motivation for interrupting the use of the frequency level convergence scheme is a network-initiated procedure that fails if the frequency level convergence scheme is used. Preferably. a network procedure involves connecting to a CN core network domain. The core network domain “CN” is at least one of the following: packet switched area “PS” and channel switched area “CS”.

[103] In another aspect of the invention, a network procedure includes at least a PRACH physical access channel procedure, an RRC radio resource control procedure for transmitting information to a network, a MAC medium access control procedure for transmitting data to the network and the cell selection procedure at a given frequency in accordance with the instructions received from the network.

[104] In yet another aspect of the invention, the motive for interrupting the use of the frequency level convergence circuit includes receiving a message initiating a reconfiguration procedure. Alternatively, the motivation for interrupting the use of the frequency level convergence scheme involves initiating a cell selection procedure at a given frequency in accordance with an indication received from the network.

[105] Preferably, the interruption of the use of the frequency level convergence circuit continues until the timer expires. The timer starts when the frequency level convergence scheme is stopped for the first time, when the network-initiated procedure for accessing the physical subscriber communication channel “PRACH” fails, when the network access control procedure “MAC” initiated for network transmission of data to the network fails, or when the network-initiated cell selection procedure at a given frequency fails in accordance with the instruction received from the network.

[106] The timer should be received from the network in a message with system information. Alternatively, the duration of the timer is a fixed value.

[107] Preferably, the method further includes selecting a cell at a frequency other than the preferred frequency. Further, the method further includes initiating a procedure by the network and continuing to interrupt the use of the frequency level convergence circuit until the end of the network-initiated procedure. Furthermore, the method further includes initiating a procedure by the network and disconnecting from the domain of the core network “CN” at the end of the procedure initiated by the network.

[108] In yet another embodiment of the present invention, a mobile terminal for selecting a cell in a wireless communication system includes means for connecting to a multicast service having a preferred frequency, means for using a frequency level convergence circuit to select a cell where frequency level convergence circuit provides cell selection at the preferred frequency, and means for interrupting the use of the convergence scheme of the frequency levels upon the occurrence of some motive reason. Preferably, the multicast service is an MBMS multimedia broadcast / multicast service.

[109] In one aspect of the invention, the motivation for interrupting the use of the frequency level convergence scheme is a network-initiated procedure that fails when using the frequency level convergence scheme. Preferably, the network procedure includes a connection to the core network domain “CN”. The core network domain “CN” is at least one of the following: packet switched area “PS” and channel switched area “CS”.

[110] In yet another aspect of the invention, a network procedure includes at least a PRACH physical access channel procedure, an RRC radio resource control procedure for transmitting information to a network, a MAC medium access control procedure for transmitting data to the network and the cell selection procedure at a given frequency in accordance with the instructions received from the network.

[111] In yet another aspect of the invention, the motive for interrupting the use of a frequency level convergence circuit includes receiving a message initiating a reconfiguration procedure. Alternatively, the motivation for interrupting the use of the frequency level convergence scheme involves initiating a cell selection procedure at a given frequency in accordance with an indication received from the network.

[112] Preferably, the interruption of the use of the frequency level convergence circuit continues until the timer expires. The timer starts when the frequency level convergence scheme is stopped for the first time, when the network initiated procedure for accessing the physical subscriber channel “PRACH” fails, when the network access control procedure “MAC” initiated for network transfer to the network fails, or when the network-initiated cell selection procedure at a given frequency fails in accordance with the instruction received from the network.

[113] The timer should be obtained from the network in a message with system information. Alternatively, the duration of the timer is a fixed value.

[114] Preferably, the mobile terminal further includes means for selecting a cell at a frequency other than the preferred frequency. Further, the mobile terminal further includes means for initiating the network procedure and means for continuing to interrupt the use of the convergence scheme of the frequency levels until the end of the network-initiated procedure. In addition, the mobile terminal further includes means for initiating the network procedure and means for disconnecting from the domain of the core network "CN" at the end of the network initiated procedure.

[115] It should be understood that the foregoing general description and the following detailed description of the present invention are illustrative and explanatory and are intended to further clarify the claims.

Brief Description of the Drawings

[116] The accompanying drawings, which are included to better understand the invention and form part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the present invention. The properties, elements and aspects of the invention, identically indicated in the various drawings, represent the same, equivalent or similar properties, elements or aspects in accordance with one or more implementations.

[117] Figure 1 shows a block diagram of the network structure of a conventional universal mobile telecommunications system "UMTS".

[118] Figure 2 shows a block diagram of the structure of a radio interface protocol between a terminal and a network according to 3GPP radio access network standards.

[119] Figure 3 shows the mapping of logical channels to transport channels in a mobile terminal.

[120] Figure 4 shows the mapping of logical channels to transport channels in a network.

[121] Figure 5 shows the possible transitions between modes and states in the network of the universal mobile telecommunications system "UMTS".

[122] FIG. 6 illustrates a decision process for selecting a cell.

[123] FIG. 7 illustrates a process for providing a specific multicast service using a multicast mode.

[124] On Fig shows the process of providing services in the broadcast mode.

[125] FIG. 9 shows a flow of a session from a network perspective.

[126] Figure 10 shows a diagram of a message transmission on a physical subscriber channel "PRACH".

[127] FIG. 11 illustrates an interruption in the use of a frequency level convergence circuit in accordance with one embodiment of the present invention.

[128] FIG. 12 illustrates an interruption in the use of a frequency level convergence circuit using a timer in accordance with one embodiment of the present invention.

Preferred Embodiments

[129] The present invention relates to a “UE” terminal that has joined a service for which a “preferred frequency” (preferred radio frequency) is defined, but the UE does not, under certain conditions, use a “frequency level convergence” scheme. For example, the frequency level convergence scheme should not be used when the UE is trying to make a new call or when the UE is unable to access the network at the preferred frequency using a method that facilitates the preferred frequency of the MBMS multimedia broadcast / multicast subscription service ".

[130] There are several ways to determine whether a UE should stop using a method that facilitates cell selection at a given “preferred frequency”. Preferably, when the use of the frequency level convergence scheme for the preferred frequency is interrupted, the use of this scheme should be discontinued for any service for which the preferred frequency is the predetermined frequency.

[131] According to a first embodiment of the present invention, the UE terminates the use of the frequency level convergence scheme when a certain situation occurs as a result of the use of the frequency level convergence scheme. Preferably, during the PRACH physical access channel procedure, when the UE receives a notification of the MAC access control layer that the collision avoidance process has failed at the physical level, or when the UE receives a message that there is no acknowledgment of receipt of “NACK” on the access indication channel “AICH”, or does not receive any from all base stations of “Nodes B”, or when the procedure of the MAC access control layer for data transmission on the preferred frequency ended in failure as a result of the use by the UE terminal of the frequency level convergence scheme, the UE terminal ceases to use this scheme.

[132] According to a second embodiment of the present invention, the UE terminates the frequency level convergence scheme when the UE needs to perform a certain procedure, for example, when the UE tries to make an emergency call. Another specific procedure occurs when the “NAS” levels (levels not directly related to providing medium access) instruct the “AS” level (level related to providing medium access) of the “UE” terminal to establish a connection with the core network domain “CN "For a specific purpose, for example," Initiating a Dialogue Call "," Initiating a Streaming Call "," Initiating an Interactive Call "," Initiating a Background Call "," Initiating a Call to Transfer Subscriber Traffic "," Terminating Dialogue Call, Stop Streaming Call, End Call Interactive, End Call Background, Emergency Call, re-select a cell between different radio access technologies, “Indicate a cell change between different radio access technologies”, “Registration”, “ Interruption of connection ”,“ Initiation of the Exchange of High Priority Signals ”. “Initiating the Exchange of Low Priority Signals”, “Repeat Call”, “Terminating the Exchange of High Priority Signals”, “Terminating the Exchange of Low Priority Signals”, “Terminating Communication for an Unknown Reason” or for any subset of these purposes.

[133] According to a third embodiment of the present invention, the UE terminates the frequency level convergence scheme when the UE receives a cell selection request at a given frequency while in the CELL_FACH, CELL_PCH, URA_PCH state or standby time.

[134] When the UE terminates the use of the frequency level convergence circuit for one of the above reasons, it also becomes necessary to determine a method for restarting the frequency level convergence circuit. Preferably, the motive for restarting the frequency level convergence circuitry may be when the procedure that initiated the interruption of the frequency level convergence circuitry is completed with or without success. Alternatively, at the time of interruption of the use of the convergence scheme of the frequency levels, the UE terminal may start the timer “T _{freq_conv_int} .”. At the end of the timer, the use of the convergence scheme of the frequency levels resumes. Accordingly, this limits the interruption of the use of the convergence scheme of the frequency levels. Preferably, the timer is broadcast in the system information.

[135] FIG. 11 illustrates a method for making an emergency call by a UE with respect to a frequency level convergence circuit. Initially, the UE terminal in the CELL_FACH, CELL_PCH, URA_PCH or standby state starts using the frequency level convergence circuit (step 1). This allows the UE to re-select the preferred frequency. Then, when the “NAS” level instructs the “AS” level that a connection to the core network domain “CN” is to be established, a value corresponding to a specific reason is transmitted to the UE (step 2).

[136] Depending on the reason, the UE may stop using the frequency level convergence scheme (step 3). Accordingly, when the “UE” terminal stops using the frequency level convergence circuit, the “UE” terminal changes the method for determining the quality of neighboring cells. If the UE needs to establish a connection with the core network domain when the UE is in standby (sleep) state, CELL_FACH, CELL_PCH, or URA_PCH, it means that the UE must send a message for example, “Cell Update”, “Request for an RRC connection” and / or “Initial Direct Transfer”, via the physical subscriber channel “PRACH” of the base station “Node B” (step 4).

[137] When the current cell or cells at the current frequency are loaded, access to the physical PRACH subscriber channel at the current frequency may fail (step 5). In the end, the UE will re-select the cell at a different frequency as the preferred frequency, since the convergence scheme of the frequency levels is no longer used (step 6). After the cell is re-selected, access to the physical PRACH subscriber channel will have a better chance of success, since the best cell is selected (step 7).

[138] Upon completion of the call, the connection to the core network domain “CN” is terminated (step 8). Then, the “UE” terminal restarts the use of the scheme of convergence of the frequency levels, if this use is also allowed (step 9).

[139] FIG. 12 illustrates a method for interrupting the use of a frequency level convergence circuit by a timer based UE. First, the UE terminal in the CELL_FACH, CELL_PCH, URA_PCH or standby state starts using the frequency level convergence circuit (step 1). This allows the UE to re-select the preferred frequency.

[140] Further, any of several events may occur (action 2). For example, the “NAS” level may indicate to the “AS” level that a connection to the core network domain “CN” should be established, and a value corresponding to a specific reason is transmitted to the “UE” terminal. Or, the RRC radio resource management procedure is launched, which requires uplink transmission. In addition, an uplink data transmission procedure may be started. Or the UE may be instructed to select a cell at a given preferred frequency.

[141] Accordingly, the UE terminates the use of a frequency level convergence circuit. When the “UE” terminal stops using the frequency level convergence circuit, the “UE” terminal changes the method for determining the quality of neighboring cells. In addition, upon terminating the use of the circuit, the UE starts the timer T _{freq_conv_int} . The duration of the timer can be fixed, or the terminal "UE" can use the value read in the system information.

[142] Then, the “UE” terminal transmits data to the base station to “Node B” via the physical PRACH subscriber communication channel (step 4). When the current cell or cells at the current frequency are loaded (s), access to the physical PRACH subscriber channel at the current frequency may fail (step 5).

[143] An alternative to starting the timer “T _{freq_conv_int} ” in _step 3 is to start it at the moment when the first procedure for accessing the physical subscriber channel “PRACH” failed (step 6). The procedure for accessing the physical subscriber channel “PRACH” may fail due to receiving a message that there is no confirmation of receipt of “NACK”, not receiving a response message, or if the mechanism for repeating the level of access control to the MAC medium expires, resulting in a transmission data further becomes impossible. The duration of the timer can be fixed, or the terminal "UE" can use the value read in the system information.

[144] As a result, the UE will re-select the cell at a different frequency as the preferred frequency, since the convergence scheme of the frequency levels is no longer used (step 7). After the cell is re-selected, access to the physical PRACH subscriber channel will have a better chance of success, since the best cell is selected (step 8).

[145] When the timer "T _{freq_conv_int} " _expires and after the call ends, the connection to the core network domain "CN" is disconnected (step 9). Then, the UE terminal restarts the use of the frequency level convergence scheme, if its use is also allowed (step 10).

[146] Accordingly, the present invention ensures that a UE that has joined the MBMS multimedia broadcast / multicast service has the same or similar chances of success in establishing a new call / emergency call or transferring data such as the same terminal "UE", which has not joined the multimedia broadcast / multicast service "MBMS".

[147] Although the present invention has been described in the context of mobile communications, it can also be used in many wireless communication systems using mobile devices, such as PDAs and laptops equipped with wireless features. In addition, the use of certain terms to describe the present invention should not limit the scope of the present invention to certain type of wireless communication systems, such as the UMTS universal mobile communication system. The present invention is also applicable to other wireless communication systems using various wireless interfaces and / or physical layers, for example TDMA (time division multiple access), CDMA (code division multiple access), FDMA (frequency division multiple access), WCDMA (broadband multiple access with channel separation), etc.

[148] Preferred embodiments of the present invention can be implemented as a method, device, or industrial product using standard programming and / or hardware, for the production of software, firmware, hardware, or any combination thereof. The term “industrial product” as used herein refers to firmware or logic elements embedded in hardware logic (eg, integrated circuit, user programmable gate array (FPGA), application specific integrated circuit (ASIC), etc.) or computer storage media (e.g. media with magnetic storage media (e.g. hard drives, floppy disks, tape drives, etc.), optical storage devices (compact discs (CD-ROMs), optical disks, etc.), volatile and non-volatile dependent memory devices (for example, EEPROM - electronically reprogrammable read-only memory), ROM (read-only memory (ROM)), PROM (programmable read-only memory (ROM)), RAM (random access memory (RAM)), DRAM (dynamic RAM), SRAM (static RAM), firmware, programmable logic, etc.).

[149] Firmware on a computer-readable medium is accessible to the processor and can be executed by it. Embedded programs in which preferred embodiments of the present invention are implemented can be accessed through a transmission medium or through a network file server. In such cases, an industrial product that uses computer programs may contain a transmission medium, such as a network transmission line, wireless means of communication, propagation of signals through space, radio waves, infrared signals, etc. Of course, a person skilled in the art will recognize that many modifications can be made in this configuration without departing from the scope of the present invention, and that the industrial product may contain any storage medium known in the art.

[150] The above embodiments and advantages are merely examples and do not limit the present invention. The presented principle can be easily applied to other types of equipment. The description of the present invention is illustrative and does not limit the scope of the claims. For qualified professionals, many options and modifications will be apparent. In the claims, the paragraphs formulating the means and functions encompass the structure described herein as performing the considered function, and not only structural equivalents, but also equivalent structures.

Claims (47)

1. The method of interrupting the use of the circuit convergence of the frequency levels in a wireless communication system, including:
receiving a notification of a multicast service having a preferred frequency;
using a convergence scheme of frequency levels to select a cell, wherein the convergence scheme of frequency levels supports cell selection at a preferred frequency, and
interruption of the use of the scheme of convergence of frequency levels after receiving a message about the initiation of the reconfiguration procedure. 2. The method of claim 1, wherein the multicast service is an MBMS multimedia broadcast / multicast service. 3. The method according to claim 1, further comprising interrupting the use of the frequency level convergence circuit after the network-initiated procedure using the frequency level convergence scheme fails. 4. The method according to claim 3, where the procedure in the network includes connecting to the domain of the core network "CN". 5. The method according to claim 4, where the domain of the core network "CN" is at least one of the following:
area with packet switching "PS"; and a circuit switched area “CS”. 6. The method according to claim 3, where the network procedure includes at least one of the following:
the procedure for accessing the physical subscriber channel “PRACH”;
RRC radio resource management procedure for transmitting information to the network;
MAC access control procedure for transmitting data to the network; and
cell selection procedure at a given frequency in accordance with the instructions received from the network. 7. The method according to claim 1, where the reconfiguration procedure includes selecting a cell at a given frequency in accordance with an indication received from the network. 8. The method according to claim 1, where the interruption of the use of the circuit convergence of the frequency levels continues until the timer expires. 9. The method of claim 8, wherein the timer starts when the use of the frequency level convergence circuit is interrupted for the first time. 10. The method of claim 8, where the timer starts when the network-initiated procedure for accessing the physical subscriber communication channel “PRACH” fails. 11. The method of claim 8, where the timer starts when the network-initiated MAC access control procedure for transmitting data to the network fails. 12. The method of claim 8, where the timer starts when the network-initiated cell selection procedure at a given frequency fails in accordance with an indication received from the network. 13. The method of claim 8, where the value for the duration of the timer is obtained from the network in a message with system information. 14. The method of claim 8, where the value for the duration of the timer is a fixed value. 15. The method according to claim 1, further comprising selecting a cell at a frequency other than the preferred frequency. 16. The method according to claim 1, in which the use of the circuit convergence of the frequency levels is interrupted only if the mobile terminal is not in the CELL-DCH state. 17. A mobile terminal for interrupting the use of the scheme of convergence of the frequency levels in a wireless communication system, including:
means for receiving notification of a multicast service having a preferred frequency;
means for using the convergence scheme of the frequency levels to select a cell, where the convergence of the frequency levels involves selecting a cell at a preferred frequency; and
means for interrupting the use of the convergence scheme of the frequency levels after receiving a message about initiating the reconfiguration procedure. 18. The mobile terminal of claim 17, wherein the multicast service is a MBMS multimedia broadcast / multicast service. 19. The mobile terminal of claim 17, further comprising interrupting the use of the frequency level convergence scheme when the network-initiated procedure using the frequency level convergence scheme fails. 20. The mobile terminal according to claim 19, where the procedure in the network includes establishing a connection with the domain of the core network "CN". 21. The mobile terminal according to claim 20, where the domain of the core network "CN" is at least one of the following:
area with packet switching "PS"; and the circuit switched area "CS";. 22. The mobile terminal according to claim 19, where the network procedure includes at least one of the following:
the procedure for accessing the physical subscriber channel “PRACH”;
RRC radio resource management procedure for transmitting information to the network;
MAC access control procedure for transmitting data to the network; and
cell selection procedure at a given frequency in accordance with the instructions received from the network. 23. The mobile terminal according to 17, where the condition for interrupting the use of the convergence scheme of the frequency levels includes receiving a message initiating the reconfiguration procedure. 24. The mobile terminal of claim 17, wherein the reconfiguration procedure includes selecting a cell at a predetermined frequency in accordance with an indication received from the network. 25. The mobile terminal according to 17, where the interruption of the use of the circuit convergence of the frequency levels continues until the timer expires. 26. The mobile terminal of claim 25, wherein the timer starts when the use of the frequency level convergence circuit is interrupted for the first time. 27. The mobile terminal according A.25, where the timer starts when the network-initiated procedure for accessing the physical subscriber communication channel “PRACH” fails. 28. The mobile terminal of claim 25, wherein the timer starts when the network-initiated MAC access control procedure for transmitting data to the network fails. 29. The mobile terminal of claim 25, wherein the timer starts when the network-initiated cell selection procedure at a predetermined frequency fails in accordance with an indication received from the network. 30. The mobile terminal of claim 25, wherein the value for the timer action time is received from the network in a message with system information. 31. The mobile terminal according A.25, where the value for the duration of the timer is a fixed value. 32. The mobile terminal of claim 17, further comprising means for selecting a cell at a frequency other than the preferred frequency. 33. The mobile terminal according to claim 17, wherein means for interrupting the use of the frequency level convergence scheme interrupt the use of the frequency level convergence scheme only if the mobile terminal is not in the CELL-DCH state. 34. A method for allowing a mobile terminal to interrupt the use of frequency level convergence schemes in a wireless communication system, including:
transmitting a notification of a multicast service having a preferred frequency, wherein said preferred frequency refers to the selection by a mobile terminal of a cell using a frequency level convergence circuit supporting cell selection at a preferred frequency; and
transmitting a message initiating a reconfiguration procedure for the mobile terminal to cause interruption in the use of the frequency level convergence scheme of the mobile terminal. 35. The method according to clause 34, in which the multicast service is a multimedia broadcast / multicast service "MBMS". 36. The method according to clause 34, further comprising initiating the execution by the mobile terminal of the procedure while the mobile terminal uses the frequency level convergence scheme. 37. The method according to clause 36, in which the specified procedure of the mobile terminal includes establishing a connection with the domain of the core network "CN". 38. The method according to clause 37, in which the domain of the core network "CN" is at least one of the following:
area with packet switching "PS"; and a circuit switched area “CS”. 39. The method according to clause 36, in which the procedure with the mobile terminal includes at least one of the following:
the procedure for accessing the physical subscriber channel “PRACH”;
RRC radio resource management procedure for transmitting information to the network;
MAC access control procedure for transmitting data to the network; and
cell selection procedure at a given frequency in accordance with the instructions received from the network. 40. The method according to clause 34, further comprising transmitting an indication to the mobile terminal, the indication informing the mobile terminal to select a cell at a predetermined frequency during the reconfiguration procedure. 41. The method according to clause 34, further comprising transmitting system information to the mobile terminal, the system information including a timer value relating to the duration of the interruption of the use of the frequency level convergence scheme. 42. The method according to paragraph 41, in which the value for the timer is a fixed value. 43. A network that allows a mobile terminal to interrupt the use of frequency convergence schemes in a wireless communication system, comprising:
a transmitter for transmitting messages to the mobile terminal;
a controller for controlling said transmitter to transmit to the mobile terminal a message indicating a multicast service having a preferred frequency and a reconfiguration message to initiate a reconfiguration procedure for the mobile terminal,
wherein the preferred frequency refers to the selection by the mobile terminal of a cell using a frequency level convergence scheme supporting cell selection at a given frequency, the reconfiguration message causing interruptions in the use of the frequency terminal level convergence scheme of the mobile terminal. 44. The network of claim 43, wherein the multicast service is an MBMS multimedia broadcast / multicast service. 45. The network of claim 43, wherein said controller further initiates execution of the procedure with the mobile terminal, while the terminal uses a frequency level convergence scheme. 46. The network according to item 45, in which the specified procedure is performed with the mobile terminal, includes establishing a connection with the domain of the core network "CN". 47. The network according to item 46, in which the domain of the core network "CN" represents at least one of the following:
area with packet switching "PS"; and
CS-switched area.

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