Duplex operation in a cellular communication system

ES 2 348 113 T3

DESCRIPTION

Duplex operation in a cellular communication system.

Field of the invention

The invention relates to duplex operation in a cellular communication system and in particular, although not exclusively, to the selection of suitable duplex operation in a 3-cell cellular communication system.^to Generation.

Background of the invention

In a cellular communication system, a geographic region is divided into several cells, each of which is served by a base station. The base stations are interconnected by a fixed network that can communicate data between the base stations. A mobile station is served via a radio link by the base station of the cell within which the mobile station is located.

As a mobile station moves, it can move from the coverage of one base station to the coverage of another, that is, from one cell to another. As the mobile station moves towards a base station, it enters an overlapping coverage region of two base stations and, within this overlapping region, makes a change so that it is supported by the new base station. As the mobile station moves further into the new cell, it continues to be supported by the new base station. This is known as a mobile station handover or handover between cells.

A typical cellular communication system typically extends its coverage over an entire country and comprises hundreds or even thousands of cells supporting thousands or even millions of mobile stations. Communication from a mobile station to a base station is known as an uplink, and communication from a base station to a mobile station is known as a downlink.

The fixed network interconnecting the base stations can be operated to route data between any two base stations, thereby enabling a mobile station in one cell to communicate with a mobile station in any other cell. Additionally, the fixed network comprises gateway functions to interconnect with external networks such as the Public Switched Telephone Network (PSTN), thus allowing mobile stations to communicate with fixed telephones and other communication terminals connected by a fixed line. In addition, the fixed network comprises much of the functionality required to manage a conventional cellular communications network, including functionality to route data, admission control, resource allocation, subscriber billing, mobile station authentication, and so on. .

Currently, the most ubiquitous cellular communications system is the 2nd generation communications system known as the Global System for Mobile communications (GSM). A more detailed description of the TDMA GSM communication system can be found in "The GSM System for Mobile Communications", by Michel Mouly and Marie Bernadette Pautet, Bay Foreign Language Books, 1992, ISBN 2950719007.

Currently, 3rd generation systems are being deployed to further improve the communication services provided to mobile users. One of these systems is the Universal Mobile Telecommunications System (UMTS), which is currently being deployed. In "WCDMA for UMTS", Harri Holma (editor), Antti Toskala (Editor), Wiley & Sons, 2001, ISBN 0471486876, you can find a more detailed description of CDMA and specifically of the CDMA Broadband (WCDMA) mode of UMTS . Third generation cellular communication systems are standardized in the 3rd Generation Partnership Project (3GPP).

In a cellular communication system, user equipment is attached to one (or more) base stations wirelessly. User equipment is attached to base stations according to parameters such as signal quality for the base station, system information signaled from the base station (where the system information may contain parameters such as the identity of the network operator ), handover commands from the network (in which a base station may force user equipment to join a different network due to issues such as relative signal quality, the traffic load on the base stations, etc.), etc.

Fig. 1 illustrates an example of user equipment that is incorporated into base stations of two different networks. The figure further illustrates that the two networks broadcast system information to all user equipment in the geographic area covered by the networks. User equipments are incorporated into base stations, not only based on signal strength, etc., but also based on the network identity that is broadcast in this system information (hence subscribers of the first network only join base stations of the first network and subscribers of the second network only join base stations of the second network). The dashed lines in Fig. 1 illustrate builds between user equipment and base stations.

In 3GPP, a user equipment searching for a cell to join will generally attempt to join the cell from a pre-configured list that meets certain quality criteria (such as signal strength). The user equipment may comprise, for example, a preconfigured list of possible frequencies to

ES 2 348 113 T3 suitable candidate cells (these frequencies can be programmed into a Subscriber Identity Module (SIM) where the SIM allows an operator to customize the user equipment to only search the frequencies that belong to that operator of the net). When a user equipment has identified a suitable cell, it will first camp in it and extract the downlink frequency from the preconfigured list.

The 3GPP specifications specify that, for the 3GPP Frequency Duplex Division (FDD) mode, the uplink and downlink frequencies are paired in an explicit relationship. Uplink frequency signaling methods in downlink messages are also considered for 3GPP extensions to new frequency bands, eg in technical recommendation TR25.889. Thus, if the uplink frequency is known, the uplink frequency is also known.

In 3GPP Time Division Duplex (TDD) mode, only a single frequency is used for the uplink and downlink, and the separation between them is achieved in the time domain. Thus, TDD uses an unpaired spectrum approach, in which the same frequency is used in both directions. In systems of this type, the base stations broadcast system information that contains characteristics of the random access channel and, in particular, this information comprises the number of the time slot in which RACH (Random Access Channel) transmissions are to be sent. , a list of pipeline codes to be used for the RACH, and so on.

For the FDD mode, the transmitted system information comprises information such as the details of the RACH preambles and available signature sequences. When the user equipment wishes to send a random access channel message, it transmits a signature sequence 12 timeslots in length. Upon receipt of an acknowledgment of the preamble, the user equipment then transmits an RACH message having a duration of either 15 time slots or 30 time slots (i.e. it sends an RACH during or one or two full frames).

In cellular communication systems, different duplexing modes can be used. In particular, the following two general classifications can be used:

• Full Duplex (FD) mode. In full duplex mode, the station and user equipment can transmit at the same time. In this way, the uplink and downlink transmissions can occur simultaneously for an individual user equipment. Orthogonality between the uplink and the downlink is achieved by allocating the uplink for transmission on one frequency and the downlink for transmission on another frequency. The full duplex mode therefore uses a spectrum paired approach.

• Half-duplex (HD) mode. In half-duplex mode, transmissions from a base station to a user equipment never occur simultaneously with transmissions from a user equipment to the base station. Therefore, for an individual user equipment, the uplink and downlink transmissions are never simultaneous. Orthogonality between uplink and downlink transmissions can be specifically maintained by assigning uplink transmissions to some time slots and downlink transmissions to other time slots. Half-duplex mode can be used with both paired and non-paired spectrum assignments:

o Unpaired Spectrum. Unpaired spectrum uses a single carrier for both uplink and downlink transmissions and they are separated in time. Both the user equipment and the base station operate strictly in the half-duplex mode, that is, both the user equipment and the base station either transmit or receive on the carrier frequency but do not transmit and receive simultaneously.

o Spectrum with Pairing. The paired spectrum uses a different frequency carrier for the uplink and the downlink. Thus, the uplink and the downlink are separated in the frequency domain and furthermore, for the individual user equipment, they are separated in the time domain by the half-duplex mode of operation. The user equipment operates in a strict half-duplex mode, in which it either transmits or receives. The base station operates in a half-duplex mode with respect to any one user equipment, that is, it either transmits or receives towards each user equipment, but can transmit and receive at the same time. Specifically, the base station can transmit to one user equipment while receiving from another user equipment, but it will never transmit and receive simultaneously for the same user equipment.

The use of different duplexing schemes including paired / unpaired spectrum and half / full duplex modes provides a high degree of flexibility and allows systems to be designed to meet various preferences and requirements. However, conventional systems also have several disadvantages.

For example, base stations and user equipment need to be compatible with each other and therefore use the same duplexing functionality. For example, a base station can transmit system information in a way that is compatible with the duplexing scheme used by the base station, and the same

ES 2 348 113 T3 can be received and decoded by a user equipment using the same duplexing scheme. However, if the user equipment uses a different duplexing scheme, it will not be able to receive the transmissions and therefore will not be able to join the base station.

User equipments are known that can support several different duplexing capabilities. Such a user equipment must monitor all the duplexing schemes that it can support in order to determine a suitable duplexing scheme for the base station it is trying to join. Such an approach is rigid and results in high equipment complexity and complex operation. Furthermore, known approaches do not allow full utilization of the duplexing capabilities of base stations and user equipments. For example, planning by the network may not be able to flexibly accommodate, and select from, a plurality of different duplexing capabilities in order to optimize performance.

Document WO 2004/107606 discloses a system that supports duplex transmission capacity from a UE to a Node B.

Therefore, an improved system would be advantageous and, in particular, a system that allows an increase in flexibility, an improvement in the use of duplexing capabilities, an improvement in adaptation, a reduced complexity, a simplification of the performance, a compatibility improvement and / or a performance improvement.

Summary of the invention

The invention relates to a system, a method and apparatus as set forth in claims 1, 22, 23, 25 and 26.

Accordingly, the invention preferably seeks to mitigate, alleviate or eliminate one or more of the above-mentioned drawbacks individually or in any combination.

The invention makes it possible to improve performance in a cellular communication system. Improved utilization of duplexing capabilities can be achieved. Improved interaction and / or coexistence of equipment having different duplexing capabilities can be achieved. In particular, a simplified incorporation into cells for user equipment can be achieved. For example, a single monitoring of base station duplexing capabilities information can be performed, and the need for individual monitoring of different transmissions for different duplexing modes can be omitted or reduced.

According to an optional feature of the invention, a first mode of the plurality of duplex modes is a paired spectrum duplex mode using paired uplink and downlink frequency carriers and a second mode of the plurality of duplex modes is a unpaired spectrum duplex mode using a single frequency carrier for the uplink and downlink.

The invention may allow improved performance in a system using both paired and unpaired spectrum duplex modes. Improved and / or simplified interaction or coexistence can be achieved between equipment using spectrum duplex mode with pairing and equipment using spectrum duplex mode without pairing. The paired spectrum duplex mode can use one frequency for uplink transmissions and a different paired frequency for downlink transmissions. Unpaired spectrum duplex mode can use the same frequency carrier for both uplink and downlink transmissions.

According to an optional feature of the invention, a first duplex mode out of the plurality of duplex modes is a half duplex mode and a second duplex mode out of the plurality of duplex modes is a full duplex mode.

The invention may allow for improved performance in a system using both half and full duplex modes. Improved and / or simplified interaction or coexistence can be achieved between equipment using half duplex mode and equipment using full duplex mode. In half duplex mode, the uplink and downlink transmissions do not match for an individual user equipment. In full duplex mode, the uplink and downlink transmissions can coincide for the same individual user equipment.

According to an optional feature of the invention, the first and second duplex modes are spectrum duplex modes with matching.

The invention may allow improved performance in communication systems using both half and full duplex paired spectrum communications. For example, some user equipment using paired spectrum communication may be capable of receiving and transmitting simultaneously while other user equipment may not be capable. In such systems, individual optimization can be provided.

ES 2 348 113 T3

According to an optional feature of the invention, the common transmission format is defined by one or more common transmission parameters from the group consisting of:

to. a channel bandwidth;

b. an encoding speed;

c. a modulation scheme;

d. a collation;

and. an encoding scheme; Y

F. a timing.

This can allow for reduced complexity and / or simplified operation. Specifically, in some embodiments, simplified receiving operation for user equipment can be achieved, resulting in reduced complexity and / or reduced processing resource requirements.

According to an optional feature of the invention, the first user equipment comprises: means for receiving the duplex capacity message from the base station; means for determining at least one transmission characteristic to be used in a system access request message in response to the duplex capability message from the base station; and means for transmitting the system access request message to the first base station using the at least one transmission feature.

This can allow for an improvement in performance in a cellular communication system. The feature can allow a user equipment to adapt to the duplexing capacity of the base station. The user equipment can specifically select between different possible duplexing modes by selecting the transmission characteristic accordingly.

According to an optional characteristic of the invention, the means for determining the at least one transmission characteristic are arranged to determine a carrier frequency for the system access request message, as the carrier frequency of the duplex capacity message of the base station if the base station duplex capability message indicates that the first base station supports only unpaired spectrum duplex mode operation, and to determine the carrier frequency as a frequency paired with the carrier frequency of the base station duplex capacity message if the base station duplex capacity message indicates that the first base station supports a paired spectrum duplex mode operation.

This may allow for an improvement in performance and / or a simplification of operation. The feature may provide a practical means of adapting user equipment to the duplexing capabilities of the base station.

According to an optional feature of the invention, the first user equipment comprises: means for determining a duplex capacity of the first base station in response to the duplex capacity message of the base station; and means for evaluating a matching criterion between a duplex capacity of the first user equipment and the duplex capacity of the first base station; and, wherein the first user equipment is only arranged to transmit an access message to the first base station if the matching criterion is met.

The matching criteria can determine, for example, whether the duplex capacity of the first base station and the first user equipment are compatible. The feature can enable improved performance by simplifying the coexistence of equipment with different duplexing capabilities on the same system. For example, the feature can ensure that user equipment is only attached to base stations with which it can communicate using a compatible duplexing mode.

According to an optional feature of the invention, the first user equipment comprises means for transmitting a duplex capacity characteristic of the user equipment to the first base station.

This can improve performance and can allow the base station and fixed network to optimize for, and accommodate, the duplexing capabilities of the first user equipment.

According to an optional feature of the invention, the cellular communication system further comprises a scheduler for scheduling communication with the first user equipment in response to the duplex capability characteristic of the user equipment.

This may allow for an improvement in planning and / or an optimization for the duplexing capabilities of the first user equipment. A scheduling improvement can be achieved which results in an improvement in the utilization of resources and thus an improvement in the performance of the cellular communication system as a whole.

ES 2 348 113 T3

According to an optional feature of the invention, the duplex capability of the user equipment is indicative of an ability of the first user equipment to support a half-duplex mode or a full-duplex mode. Half duplex mode and full duplex mode can be spectrum duplex modes with pairing.

This may allow an improvement in optimization depending on the half-duplex or full-duplex mode capabilities of the user equipment. In particular, the paired spectrum duplex modes can comprise both a half-duplex mode and a full-duplex mode, and performance and, particularly, scheduling performance, can be optimized for the specific mode used at the time.

According to an optional feature of the invention, the scheduler is arranged to schedule a communication subject to an uplink and downlink time orthogonality constraint for the half-duplex mode; and to schedule a communication without any uplink and downlink time orthogonality constraints for full duplex mode.

This allows for improved planning that takes into account the specific limitations of the user equipment, thereby allowing the planning performance to be optimized for current conditions. This can reduce the use of resources and can improve the performance of the communication system as a whole.

According to an optional feature of the invention, the first user equipment is arranged to understand the duplex capability characteristic of the user equipment in an access message.

This can provide a practical, low complexity and / or efficient means of communicating the duplex capability of the user equipment to the first base station. The access message can be, for example, a 3GPP RRC CONNECTION REQUEST message transported on a RACH transport channel or the equivalent message in a system evolved from 3GPP.

According to an optional feature of the invention, the first user equipment is arranged to understand the duplex capability characteristic of the user equipment in a communication confirmation message.

This can provide a practical, low complexity and / or efficient means of communicating the duplex capability of the user equipment to the first base station. The access message can be, for example, a 3GPP RRC CONNECTION SETUP COMPLETE message or the equivalent message in a system evolved from 3GPP.

According to an optional feature of the invention, the cellular communication system further comprises means for supporting a call setup procedure using a common communication scheme for the plurality of duplex modes.

This can allow for an improved and / or simplified call setup. In particular, it can allow a common call setup procedure for different duplex modes, thus allowing specific adaptation to the specific duplex mode to be delayed. The communication scheme may, for example, comply with the common transmission format. Specifically, the user equipment can request or initiate a new call setup using a signaling channel that is common for the plurality of duplex modes.

According to an optional feature of the invention, the first base station is arranged to communicate with the first user equipment during a call setup process using a half-duplex mode of operation until a call feature is received from the first user equipment. duplex capacity.

This may allow for a practical and / or simplified and / or improved call setup procedure.

According to an optional feature of the invention, the first base station is arranged to communicate with the first user equipment during a call setup process using a half-duplex mode of operation; and the first user equipment is arranged to ignore downlink transmissions in time slots used for uplink transmissions from the first user equipment to the first base station.

This can simplify operation and / or reduce complexity.

According to an optional feature of the invention, the cellular communication system is arranged to support communications in accordance with the Technical Specifications of the Association Project of 3^to Generation.

The invention can improve the performance of a 3GPP cellular communication system and systems evolved from 3G.

According to an optional feature of the invention, the cellular communication system is arranged to support communications in accordance with the System Recommendations of the Global System for Mobile Communications.

The invention can improve the performance of a cellular GSM communication system.

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These and other aspects, features, and advantages of the invention will become apparent from and with reference to the embodiment (s) described hereinbelow.

Brief description of the drawings

Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which Fig. 1 shows an illustration of a prior art cellular communication system;

Fig. 2 shows an example of a cellular communication system according to some embodiments of the invention;

Fig. 3 shows an example of frequencies used in a paired spectrum;

Fig. 4 shows an example of frequencies used in an unpaired spectrum;

Fig. 5 shows a method of determining a random access channel for TDD operation;

Fig. 6 shows a method of determining a random access channel for FDD operation;

Fig. 7 shows an example of a base station according to some embodiments of the invention;

Fig. 8 shows an example of a user equipment according to some embodiments of the invention;

Fig. 9 shows a scheduling example for a half duplex type unpaired spectrum duplex mode;

Fig. 10 shows a scheduling example for a full duplex paired spectrum duplex mode;

Fig. 11 shows a scheduling example for a spectrum duplex mode with half-duplex pairing;

Fig. 12 shows a flow chart for exemplary operation of user equipment according to some embodiments of the invention;

Fig. 13 shows a flow chart for exemplary operation of a base station according to some embodiments of the invention;

Fig. 14 shows a signaling sequence according to some embodiments of the invention;

Fig. 15 shows a signaling sequence according to some embodiments of the invention;

Fig. 16 shows a signaling sequence according to some embodiments of the invention; and Fig. 17 shows a signaling sequence according to some embodiments of the invention.

Detailed description of some embodiments of the invention

The following description refers to embodiments of the invention applicable to a 3GPP cellular communication system comprising base stations exhibiting different duplexing capabilities. However, it will be appreciated that the invention is not limited to this application but can be applied to many other cellular communication systems, including, for example, Global System Mobile Communications (GSM).

Fig. 2 illustrates an example of a 3GPP UMTS cellular communication system in which embodiments of the invention can be used.

In the example of Fig. 2, a first user equipment 201 and a second user equipment 203 are in a first cell supported by a first base station 205.

User equipment can be, for example, User Equipment (UE) of 3^to Generation, communication units, subscriber units, mobile stations, communication terminals, personal digital assistants, cell phones, portable computers, integrated communication processors or any physical, functional or logical communication element that is capable of communicating through the air interface of the cellular communication system.

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The first base station 205 is coupled to a first RNC 207. An RNC performs many of the control functions related to the air interface, including radio resource management and routing of data to and from appropriate base stations.

The first RNC 207 is coupled to a core network 209. A core network interconnects RNCs and can be operated to route data between any two RNCs, thereby enabling a user equipment in a cell to communicate with a user equipment in a cell. any other cell. Additionally, a core network comprises gateway functions to interconnect with external networks such as the Public Switched Telephone Network (PSTN), thus allowing user equipment to communicate with landlines and other communication terminals connected by a landline. In addition, the core network comprises much of the functionality required to manage a conventional cellular communications network, including functionality to route data, admission control, resource allocation, subscriber billing, user equipment authentication, and so on.

The core network 209 is further coupled to a second RNC 211 that is coupled to a second base station 213. The second base station 213 supports a third user equipment 215.

In the system of Fig. 1, the base stations have different capabilities. Specifically, some base stations may be arranged to support a TDD mode of operation in which a single carrier frequency is used for both the uplink and the downlink. Other base stations may be arranged to support an FDD mode of operation in which paired spectrum carriers are used for the uplink and downlink. Thus, some base stations can use FDD with paired spectrum while other base stations use unpaired spectrum with TDD operation.

An example of frequencies used in a paired spectrum system is shown in Fig. 3. In this figure, the uplink transmissions are in the 2,550 to 2,560 MHz frequency range and the downlink transmissions are in the 2,670 to 2,680 MHz frequency range. This paired spectrum can be used either in full duplex mode or half duplex mode.

An example of frequencies used in an unpaired spectrum is shown in Fig. 4. In this example, both the uplink and downlink transmissions are in the frequency range 2,595 to 2,605 MHz. This unpaired spectrum can be used in half duplex mode.

A user equipment joining the system will initially attempt to identify the most suitable base station based on suitable criteria such as signal strength, network identity, and so on. Having selected a suitable base station to join, the user equipment then sends a message to the selected base station informing the network of the user equipment's desire to join that base station. This connection request type message is typically sent over a random access channel (RACH). In a 3GPP system, the "RRC CONNECTION REQUEST" message is used for this purpose. This message contains details that affect the connection to be established. The connection request message may comprise, for example, information such as:

- user equipment identity (such as the International Mobile Subscriber Identity: IMSI).

- Signal measurements (such as the levels of the received beacon signals).

The network responds to the communication request message with a connection establishment message. In 3GPP systems, the "RRC CONNECTION SETUP" message can be considered a handshake message. The handshake message may comprise, for example, information such as:

- a temporary identity for the user equipment.

- uplink and downlink radio bearer details.

- details of parameters used for the search (paging).

Next, the user equipment responds to the handshake message with a connection setup completed message. In 3GPP systems, this message may correspond to the "RRC CONNECTION SETUP COMPLETE" message. The completed connection setup message may comprise, for example, information such as:

- User equipment capacity (eg data rate that user equipment can support, functions that user equipment supports, etc.).

- safety-related information.

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In 3GPP systems, a user equipment searching for a suitable serving cell will typically monitor several carrier frequencies stored in a pre-configured list. You will then select the base station that provides the best signal under current conditions.

In 3GPP systems, base stations broadcast system information comprising information of the random access channel to be used. This information is used to select and configure the appropriate random access requests. However, in conventional systems, the different duplexing methods are discussed separately and independently.

Specifically, a user equipment using a TDD unmatched spectrum duplexing mode, decodes this signaling information and uses it to determine the time slot numbers and channelization codes to use for RACH transmissions. The appropriate transmission frequency is determined directly as the same frequency as that used to receive the information from the system.

For a user equipment using a spectrum duplexing mode with FDD matching, the system information comprises information such as the details of the RACH preambles and the available signature sequences to use. When the user equipment wishes to send a random access channel message, it transmits a signature sequence 12 timeslots in length. Upon receipt of an acknowledgment for the preamble, the user equipment then transmits an RACH having a duration of either 15 time slots or 30 time slots (i.e. it sends an RACH or for a or for two complete frames).

Furthermore, the 3GPP specifications explicitly specify a relationship between the uplink and downlink frequencies. In this way, the user equipment can directly calculate the paired uplink frequency from the uplink frequency on which the system information is received.

Fig. 5 illustrates a method of determining a suitable random access channel for TDD operation, and Fig. 6 illustrates a method of determining a suitable random access channel for FDD operation.

In conventional systems, different duplexing modes have different access procedures and the determination of the appropriate RACH characteristics depends on the specific duplexing mode used by the user equipment and the base station. Specifically, a user equipment that is capable of accessing both FDD and TDD base stations must independently search for these base stations. Thus, the user equipment must first monitor for FDD system information and use it to determine a suitable FDD access channel, and then monitor for TDD system information and use the same to determine a suitable TDD access channel. This results in a complex, slow, resource-intensive and cumbersome access approach.

In the system of Fig. 2, the first base station 205 comprises a functionality to transmit a duplex capacity message from the base station to the user equipments 201, 203 using a transmission format that is common for different duplex modes. Specifically, the first base station 205 transmits system information using a transmission format that is the same regardless of whether the first base station 205 is a base station using paired or unpaired spectrum and regardless of whether the base station can support full duplex or half duplex only. Specifically, a TDD and FDD base station can transmit system information on the same frequency and use the same transmission schemes.

The duplex capability message provides information on which duplex modes the first base station 205 supports. Therefore, the duplex capability message can indicate whether the base station can support the paired / unpaired and / or full-duplex spectrum modes. / half duplex. The duplex capability message is transmitted using a signal structure that is common for both paired and non-paired operation.

Figure 7 illustrates the first base station 205 of Fig. 2 in more detail. Base station 205 comprises a duplex data generator 701 that is coupled to a transmit controller 703 which is coupled to a transceiver 705.

The duplex data generator 701 generates duplex information that will be broadcast by the base station 205. The duplex information can specifically identify whether the base station is a base station using paired or unpaired spectrum. If the base station uses paired spectrum, the duplex information further indicates whether the base station can support user equipment in half-duplex mode, user equipment in full-duplex mode, or user equipment in both half-duplex and full-duplex modes.

The duplex data is sent to the transmitting controller 703, which inserts the data into a suitable system information message to be broadcast. The transmitting controller 703 may combine the duplex data with data received from other functional entities and broadcast for other purposes. Therefore, the transmission controller 703 generates a broadcast system information message and controls the transceiver 705 to broadcast this message on a suitable channel.

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The transmission controller 703 specifically controls the transceiver to broadcast a duplex capability message in the form of the system information broadcast message. Transmission controller 703 also controls the transmission format that is used for the message. The same transmission format is used regardless of the duplex capability of the base station. Thus, the transmitting controller 703 controls the transceiver to transmit the duplex capacity message in the same time slots and using the same carrier frequency regardless of the specific duplex capacity of the base station 205. The broadcast message is further transmitted using the same spreading code, modulation scheme, error correction scheme, channel bandwidth, data rate, interleaving scheme, and other transmission parameters.

Consequently, user kits 201, 203 only need to receive a single message with well-known predetermined parameters in order to determine the duplex capability of base station 205.

A first user equipment 201 seeking to join the system can decode the received duplex capacity message and use the resulting information to determine a suitable access channel and access transmission scheme. The first user equipment 201 may further use the received duplex capacity information to determine whether the capacity of the first user equipment 201 is compatible with that of the first base station 205.

Fig. 8 illustrates the first user kit 201 in more detail. The user equipment 201 comprises a transceiver 801. The transceiver 801 can be operated to monitor for the duplex capacity message from the first base station 205. Specifically, the transceiver 801 receives a predetermined carrier frequency at the time intervals. used for the communication channel that carries the duplex capability message. For example, the duplex capability message may be included in a system information message that is monitored and received by the 801 transceiver.

Since the same transmission format is used for different duplexing modes, the transceiver 801 can simply monitor a single channel regardless of which duplexing mode is used by the base station 205. The transceiver 801 is coupled to a compatible processor 803 , and when the transceiver 801 receives the duplex capability message, it is forwarded to the compatibility processor 803.

The compatibility processor 803 is arranged to evaluate a matching criterion in relation to the duplex capabilities of the first user equipment 201 and the first base station 205.

The compatibility processor 803 can specifically determine which duplexing mode the base station uses and can compare this to the duplexing mode (s) that the user equipment 201 can support. If none of the duplexing modes that the base station 205 can support can be supported by the first user equipment 201, the compatibility processor 803 determines that the matching criteria has not been met and causes the user equipment to abandon the first one. base station 205 to search for another suitable base station to join.

If the first user equipment 201 and the first base station 205 can support the same duplexing mode, the compatibility processor 803 causes the user equipment 201 to prepare to join the first base station 205.

For example, the duplex capability message may indicate that base station 205 uses unpaired spectrum. If the first user equipment 201 can only support a paired spectrum, the compatibility processor 803 controls the user equipment 201 to search for another base station as the first base station 205 that the user equipment 201 cannot support. However, if the first user equipment 201 also supports unpaired spectrum, the first base station 205 can support the first user equipment 201, and the compatibility processor 803 prepares the user equipment 201 to access the first base station. 205.

In the example, the compatibility processor 803 is coupled to a RACH feature processor 805. When the compatibility processor 803 has identified a compatible base station, the RACH features processor 805 is informed of this. In response, the RACH feature processor 805 proceeds to determine suitable features to be used in order to access the first base station 205.

Specifically, the RACH feature processor 805 identifies the appropriate RACH channel to use. This includes determining the appropriate frequency and timing to use to access the first base station using the identified duplex format.

In the specific example, the user equipment 201 is a combined TDD and FDD user equipment that can support both paired and non-paired spectrum modes. In the example, the RACH feature processor 805 determines whether the identified base station uses paired or unpaired spectrum. If base station 205 uses a paired spectrum, the carrier frequency to use for any uplink RACH attempt is determined as the carrier frequency of the uplink frequency spectrum that is paired with the carrier frequency used to transmit the uplink information. system in the downlink frequency spectrum. However, if base station 205 uses unpaired spectrum, the carrier frequency for

ES 2 348 113 T3 the uplink RACH attempts are determined as the carrier frequency used for broadcasting information from the downlink system.

It will be appreciated that other parameters and characteristics, for the RACH channel, other than the carrier frequency can be determined. For example, a suitable timing, spreading code, signature or other parameter may additionally or alternatively be determined.

The RACH feature processor 805 is coupled to a RACH transmission controller 807 to which the transmission characteristics determined by the RACH feature processor 805 are supplied for the access message. The RACH transmission controller 807 is coupled to the transceiver 801 and controls the transmission of the access message using the determined transmission characteristic. Specifically, the RACH transmission controller 807 can generate the access message and deliver the same to the transceiver at the appropriate time. Additionally, you can control the transmission parameters to be applied by the transceiver, such as the appropriate carrier frequency.

Therefore, the first user equipment 201 can automatically adapt to the duplexing capacity of the first base station 205 without requiring the first user equipment 201 to support separate monitoring and enrollment for each duplexing mode. Instead, a common process and functionality can be used for any base station, thereby reducing the complexity and processing load of user equipment 201.

In the example of Fig. 8, the first user equipment 201 further comprises a functionality for transmitting information of the duplex capacity of the user equipment 201 to the first base station 205.

Specifically, the RACH transmission controller 807 is coupled to a duplex capacity processor 809 that is arranged to generate duplex data indicative of the duplex capacity of the user equipment 201 and to supply the same to the RACH transmission controller 807 for transmission. towards base station 205.

Specifically, the duplex capacity information can be transmitted to the first base station 205 in the access message itself. Alternatively or additionally, the duplex capacity information may be transmitted in another message in the call setup procedure. For example, the duplex capacity information may be transmitted in a communication completed message transmitted from user equipment 201 to first base station 205 in response to a call setup message from first base station 205.

The duplex capacity information from the first user equipment 201 may specify the duplexing modes that the user equipment 201 can support. Specifically, the duplex capacity information may specify whether the user equipment can support spectrum operation with and / or without pairing. Additionally or alternatively, the duplex capability information may specify whether the user equipment 201 can support half and / or full duplex operation.

As a specific example, the cellular communication system may comprise some user equipment that operates in spectrum paired configurations and is only capable of supporting half-duplex operation, while other user equipment operating in the paired spectrum configuration can support full duplex in which uplink and downlink transmissions can occur simultaneously for an individual user equipment. In systems of this type, the duplex capacity information transmitted from user equipments can indicate whether they can support full duplex mode or if they can only support half duplex mode.

The duplex capacity information received from the user equipment 201 can be used by the system to improve performance and for optimization with respect to the current duplex capabilities of the user equipment. For example, planning for user equipment can be done in such a way that duplex capacity information is taken into account. For example, for user equipment that can only support half-duplex mode, planning can be performed such that the uplink and downlink transmissions do not match for individual user equipment, while planning for user equipment that can supporting full duplex mode can fully utilize all time slots in both directions without any such restriction. This can allow an improvement in planning efficiency and can improve resource utilization resulting in improved performance and increased capacity of the cellular communication system as a whole.

In the following, more details of some embodiments of the invention will be described with specific reference to three different types of base station duplex capability, which can occur frequently in a 3GPP cellular communication system.

The first type of base station is an unpaired half duplex base station that can only support unpaired spectrum communication that inherently must be half duplex (since the uplink and downlink transmissions cannot coincide). The second type is a mode base station

ES 2 348 113 T3 full duplex only, paired, which is a base station that supports paired spectrum but cannot guarantee that uplink and downlink transmissions for the same user equipment do not match. The third type is a paired spectrum base station capable of supporting both half and full duplex user equipment, that is, it comprises a scheduling function that can ensure that uplink and downlink transmissions for a single user equipment. half duplex user mismatch. An exemplary operation for the three different scenarios will be independently described.

Half duplex base station with unpaired spectrum

In this mode of operation, the base station broadcasts a duplex capability message indicating that the base station supports the unpaired mode of operation. Inherently, the no-pairing mode of operation (as used in TDD) results in only half-duplex mode being supported.

The user equipments decode the duplex capability message, and a specific user equipment can configure its transmitter to transmit access messages on the same carrier frequency as the downlink carrier. The access message requesting a communication may also comprise the duplexing capacity information for the user equipment, although this is not essential since the base station knows a priori that only user equipment with half-duplex mode capability will be connected to it. with unpaired spectrum.

The base station receives this message and schedules the user equipment as a half-duplex mode user equipment with unpaired spectrum.

A paired spectrum full duplex mode user equipment cannot respond to the unpaired spectrum half duplex base station (as it cannot transmit on the same carrier as the downlink), and therefore cannot join this base station (therefore it will proceed to search for another base station).

For half-duplex mode user equipment operating in unpaired spectrum, uplink transmissions are scheduled at different times than downlink transmissions. This is inherent in half-duplex operation in an unpaired spectrum. An example of such a planning is illustrated in Fig. 9.

Base station only full duplex spectrum with pairing

A paired spectrum full duplex only base station is considered to be a base station that can only operate in full duplex mode and cannot guarantee that uplink and downlink transmissions for the same user equipment will not occur. simultaneously (for example, due to a system architecture decision during base station design according to which the uplink and downlink schedulers will be totally independent).

In this mode of operation, the base station broadcasts a full duplex capability message indicating that the base station supports only full duplex in a paired spectrum.

User equipment decodes the duplex capability message, and a paired spectrum full duplex mode capable user equipment can configure its transmitter to transmit access messages on the appropriate paired uplink carrier frequency. The access message requesting a communication may further comprise the duplexing capability information for the user equipment, although this is not essential since the base station knows a priori that only user equipment with duplex mode capability will be connected to it. full.

A half duplex mode only user equipment will decode the broadcast signal from the base station and determine that the specific base station is not compatible. Therefore, the half-duplex user equipment does not attempt to join the base station in full-duplex mode only, but proceeds to search for other base stations to join.

Scheduling for a paired spectrum full duplex only base station is done according to full duplex rules (and therefore uplink and downlink scheduling can be completely independent).

Full duplex mode user equipment requires a paired spectrum for operation. Full duplex mode user equipments can be scheduled with separate schedulers on the uplink and downlink, and these uplink and downlink schedulers do not need to be connected (from the perspective of maintaining an orthogonality rule ). Although a full duplex mode user equipment can transmit on the uplink and receive on the downlink at the same time, it is not necessary for the user equipment to transmit uplink and receive downlink at the same time (and hence that to a full duplex user equipment can be assigned merely

ES 2 348 113 T3 an uplink resource, merely a downlink resource or both an uplink and a downlink resource in the same time slot).

An example of planning in a system with full duplex mode user equipment is illustrated in Fig. 10. Fig. 10 illustrates that the base station can operate with independent uplink and downlink schedulers. The figure also illustrates that some user equipments are assigned an uplink only resource in a time slot, some user equipments are assigned an uplink only resource in a time slot, and some user equipments are assigned an uplink only resource in a time slot. allocates both an uplink and downlink resource to them in a time slot.

Half and full duplex, paired spectrum base station

A paired spectrum half and full duplex base station can serve both half duplex mode user equipment and full duplex mode user equipment operating in the paired spectrum mode.

In this mode of operation, the base station broadcasts a duplex capability message indicating that the base station supports both full and half duplex modes in a paired spectrum.

The full-duplex message can be decoded by user equipment with half-duplex without pairing, half-duplex with pairing, or full-duplex with pairing. The paired half-duplex user kits will determine that they are not compatible with the base station and proceed to search for another base station. However, both full duplex and half duplex paired spectrum user equipments can proceed to access the base station.

Specifically, a full or half duplex mode user equipment can configure its transmitter to transmit on the uplink frequency that is paired with the uplink frequency on which the duplex capacity message signal is sent (the link frequency upstream may be known a priori or may be signaled, for example, in the duplex capability message).

When a user equipment (either half or full duplex mode) wants to join the network, it can transmit an access message using the paired uplink carrier frequency. This message may contain (among other things) information about the duplexing capabilities of the user equipment.

Upon receipt of the duplexing capacity information, the base station scheduler schedules user equipments based on whether they are full duplex mode user equipments or half duplex mode user equipments. For half duplex mode user equipment, the scheduler ensures that it never schedules an uplink from a user equipment at the same time as scheduling an uplink to that user equipment. For a full duplex mode user equipment, the scheduler can independently schedule an uplink and a downlink. Therefore, the same base station can serve user equipment in both half-duplex and full-duplex mode.

An example of such a scheduling operation is illustrated in Fig. 11.

It will be appreciated that, in some embodiments, the base station may allocate some time slots to be used exclusively by half-duplex mode user equipment and other time slots to be used exclusively by full-duplex mode user equipment.

In some embodiments, the base station can support a call setup procedure using a communication scheme that is common for more than one duplex mode. Specifically, the base station can receive an access request message on the uplink spectrum with pairing and continue the call setup procedure using half-duplex communication, that is, while ensuring that the uplink and downlink transmissions they do not match for the user equipment. This approach may be particularly suitable for embodiments where the duplex capability of the user equipment is not transmitted to the base station until late in the call setup procedure. In the example, the base station may operate in half duplex mode for a user equipment until the base station receives a duplexing capability message from this user equipment.

In this way, the base station works in essentially two phases from the perspective of a user equipment. In the initial phase of a connection, the base station preferably operates in the strictly half-duplex mode for user equipment until the base station receives information on the duplexing capacity of the user equipment. After the initial phase of connection, the base station operates in either full or half duplex modes for the specific user equipment depending on the duplexing capabilities of the user equipment.

For user equipment in half duplex mode, the base station schedules user equipment in such a way that for any individual user equipment, uplink and downlink resources are never scheduled at the same time. However, the base station can schedule one set of user equipments at time T on the uplink and another set of user equipments at time T on the downlink,

ES 2 348 113 T3 but these user equipment sets must not overlap. However, for full-duplex user equipment, no such restriction is necessary. Thus, the scheduler can schedule a communication subject to uplink and downlink time orthogonality constraint for the user equipments in half-duplex mode, and can schedule communication without uplink and downlink time orthogonality constraint. downlink for user equipment in half duplex mode.

In some embodiments, the base station can operate in full duplex mode during at least part of the call setup procedure for a half duplex user equipment. In such cases, the half-duplex user equipment may ignore the downlink transmissions in the time slots for which an uplink transmission is required.

Fig. 12 illustrates a flow chart for exemplary operation of user equipment capable of supporting both paired and unpaired spectrum according to some embodiments of the invention.

FIG. 13 illustrates a flow chart for an exemplary operation of a base station capable of supporting spectrum duplexing with both half and full duplex matching according to some embodiments of the invention.

In some embodiments, the user equipment may transmit the duplex capability information to the base station in a communication or access request message. In other embodiments, the user equipment may transmit the duplex capacity information to the base station in another message in the call setup procedure. For example, the user equipment may transmit the duplex capability information in a communication confirmation message, which is sent to the base station as confirmation of a handshake message transmitted from the base station to the user equipment.

For brevity, the communication or access request message will be referred to as the CONREQ message, the communication establishment message will be referred to as the CONSETUP message, and the communication confirmation message will be referred to as the CONCOMPLETE message. In a 3GPP system, the CONREQ message can be an RRC CONNECTION REQUEST message and the CONCOMPLETE message can be an RRC CONNECTION SETUP COMPLETE message.

Signaling of the duplex capacity in the CONREQ

When the duplexing capacity of the user equipment is sent in the CONREQ message, it can be sent using a RACH type channel. Preferably, the CONREQ message is sent in a different time interval (ie orthogonal) to the time interval in which the broadcast transmission is sent from the base station, although this is not strictly necessary. An example of such operation is illustrated in Fig. 14.

Alternatively, the CONREQ message can be sent in the same time interval as used for the duplex capacity message from the base station. Such an approach is suitable for a full duplex mode user equipment, although it is somewhat less suitable for a half duplex mode user equipment and requires the half duplex mode user equipment to ignore the decoding of broadcasts from the base station when the CONREQ message is transmitted. An example of such operation is illustrated in Fig. 15.

In this example, the user equipment can send the CONREQ message in the same time interval as the broadcast message, and further can decode the broadcast message even when the CONREQ message is transmitted.

Fig. 16 illustrates the same type of operation for a half-duplex mode user equipment, where the half-duplex mode user equipment does not decode the broadcast signal in the time interval in which it sends the CONREQ message (this type of performance is acceptable when the broadcast information is continually refreshed, and hence the user equipment can decode the lost broadcast information at a future time).

Signaling of the duplex capacity in the CONCOMPLETE

When the duplexing capability is sent in the CONCOMPLETE message, the CONCOMPLETE and CONREQ messages are preferably sent at different time intervals with respect to the broadcast and CONSETUP messages. When different time intervals are used until the CONCOMPLETE message is received by the base station, the base station is essentially adopting half-duplex mode operation until it receives the message detailing whether the user equipment is actually half-duplex. Since a full duplex user equipment can receive downlink by itself or transmit uplink by itself (as well as transmit and receive at the same time), User equipment can be served in both full and half duplex mode until the base station knows the duplexing capability of the user equipment (at which point the base station can transition to serve the user equipment in the optimal mode - full duplex or half duplex). Thus, the base station adopts half-duplex mode operation until it receives a duplexing capability message from the user equipment.

ES 2 348 113 T3

An example of a signaling sequence adopted when using CONCOMPLETE to signal the duplexing capability of user equipment is illustrated in Fig. 17. In the example, the signaling sequence is such that the uplink CONREQ / CONCOMPLETE messages are never in the same time slot as the broadcast or call setup messages from the base station, and hence the sequence signaling is also applicable to user equipment with half-duplex and full-duplex mode capability.

It will be appreciated that the foregoing description, for the sake of clarity, has set forth embodiments of the invention with reference to different functional units and processors. However, it will be appreciated that any distribution of functionality between different functional units or processors can be used without prejudice to the invention. For example, the illustrated functionality intended to be performed by separate processors or controllers may be performed by the same processor or controllers. Therefore, references to specific functional units should be considered only as references to suitable means of providing the described functionality and not as indicative of a strict logical or physical structure or organization.

The invention can be implemented in any suitable format including hardware, software, firmware, or any combination thereof. The invention may optionally be implemented at least partially in the form of computer software running on one or more data processors and / or digital signal processors. The elements and components of an embodiment of the invention can be physically, functionally and logically implemented in any suitable way. In fact, the functionality can be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the invention can be implemented in a single unit or it can be physically and functionally distributed among different units and processors.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the appended claims. Additionally, although a feature may appear to be described in relation to particular embodiments, those skilled in the art will recognize that, in accordance with the invention, various features of the disclosed embodiments may be combined. In the claims, the term "comprise" does not exclude the presence of other elements or steps.

In addition, for example, a single unit or processor may implement a plurality of means, elements, or method steps, even if they are individually listed. Additionally, although individual features may be included in different claims, they may possibly be advantageously combined, and inclusion in different claims does not imply that a combination of features is not feasible and / or advantageous. Furthermore, the inclusion of a feature in one category of claims does not imply a limitation to this category but, on the contrary, indicates that the feature is also applicable to other categories of claim, as deemed appropriate. Furthermore, the order of features in the claims does not imply any specific order in which the features must be put into practice, and in particular, the order of individual steps in a method claim does not imply that the steps must be performed therein. order. Rather, the stages can be performed in any suitable order.