Method and arrangement in a telecommunication system
Abstract
A method of allocating communications resources in a telecommunication system, in which the assignments of communications resources to user equipment are transmitted in a plurality of Physical Downlink Link Control Channels, PDCCH, the PDCCHs that are comprised in a control zone of each downlink subframe, the method comprising: split (36) the PDCCHs into at least one common subset of the PDCCHs and a plurality of group subsets of the PDCCHs, allowing each user equipment to decode the common subset of the PDCCHs and only a group subset of the PDCCHs, into where a respective group subset of the PDCCHs to be decoded by a user equipment is determined by the account module of a Temporary Radio Network Identifier, RNTI, of the user equipment.

Term
2.1 yearsto projected expiry
Projected expiry 7 November 2028, counted from filing; an application has no term until it is granted.
- Priority
- Filed
- Published
- Today
- Projected expiry
20 claims: 10 independent, 10 dependent
- 1ES 2 359 482 T3 REIVINDICACIONES 1. Un método de asignación de los recursos de comunicaciones en un sistema de telecomunicación, en el que las asignaciones de los recursos de comunicaciones a los equipos de usuario se transmiten en una pluralidad de Canales de Control del Enlace Descendente Físico, PDCCH, los PDCCH que están comprendidos en una zona de control de cada subtrama del enlace descendente, el método que comprende:dividir (36) los PDCCH en al menos un subconjunto común de los PDCCH y una pluralidad de subconjuntos de grupo de los PDCCH, permitiendo a cada equipo de usuario descodificar el subconjunto común de los PDCCH y solamente un subconjunto de grupo de los PDCCH, en donde se determina un subconjunto de grupo respectivo de los PDCCH que va a ser descodificado por un equipo de usuario mediante el módulo de cuenta de un Identificador Temporal de Red Radio, RNTI, del equipo de usuario.
- 2Un método como se reivindica en la reivindicación 1, en donde el comprende los PDCCH en el nivel de agregación más alto disponible. subconjunto común de los PDCCH
- 3Un método como se reivindica en la reivindicación 1, en donde el comprende todos los PDCCH posibles en un nivel de agregación. subconjunto común de los PDCCH
- 4Un método como se reivindica en la reivindicación 3, en donde el subconjunto común de los PDCCH comprende todos los PDCCH posibles en el nivel de agregación más alto disponible.
- 5Un método como se reivindica en cualquier reivindicación precedente, en donde cada subconjunto de grupo de los PDCCH comprende los PDCCH en uno o más niveles de agregación que cubren un subconjunto de elementos del canal de control.
- 6Un método como se reivindica en la reivindicación 5, en donde cada subconjunto de grupo de los PDCCH comprende todos los PDCCH posibles en todos los niveles de agregación que cubren un subconjunto de elementos del canal de control.
- 7Un método como se reivindica en cualquier reivindicación precedente, que además comprende:transmitir los mensajes de difusión en al menos un PDCCH que forma parte del subconjunto común de los PDCCH.
- 8Un método como se reivindica en cualquier reivindicación precedente, que además comprende:transmitir (38) un mensaje de asignación de recursos para un equipo de usuario en al menos un PDCCH que forma parte del subconjunto de grupo respectivo de los PDCCH.
- 9Un método como se reivindica en cualquier reivindicación precedente, que además comprende:transmitir (38) un mensaje de asignación de recursos para un equipo de usuario en al menos un PDCCH que forma parte del subconjunto común de los PDCCH.
- 10Un método como se reivindica en cualquier reivindicación precedente, que además comprende transmitir (38) un mensaje en un PDCCH que comprende un número más grande de elementos del canal de control que el requerido para el mensaje.
- 11Un método de funcionamiento de un equipo de usuario para determinar los recursos de comunicaciones asignados al mismo en una sistema de telecomunicación, en el que las asignaciones de los recursos de comunicaciones a los equipos de usuario se transmiten en una pluralidad de Canales de Control del Enlace Descendente Físicos, PDCCH, los PDCCH que están comprendidos en una zona de control de cada subtrama del enlace descendente, el método que comprende:determinar una división de los PDCCH en al menos un subconjunto común de los PDCCH y una pluralidad de subconjuntos de grupo de los PDCCH;determinar (56) un subconjunto de grupo pertinente de los PDCCH a partir de la pluralidad de los subconjuntos de grupo de los PDCCH;y descodificar (58) los PDCCH que forman el subconjunto común de los PDCCH o cada subconjunto común de los PDCCH, y descodificar solamente los PDCCH del subconjunto de grupo pertinente de los PDCCH;en donde el paso de determinar (56) el subconjunto de grupo pertinente de los PDCCH comprende el módulo de cuenta de un Identificador Temporal de Red Radio, RNTI, del equipo de usuario.
- 12Un método como se reivindica en la reivindicación 11, en donde el paso de determinar la división de los PDCCH en al menos un subconjunto común de los PDCCH y una pluralidad de los subconjuntos de grupo de los PDCCH comprende:ES 2 359 482 T3 determinar (50) un número de elementos del canal de control en cada subtrama;y determinar (52) a partir de dicho número de elementos del canal de control en cada subtrama si se ha hecho una división en dos o más subconjuntos de grupo de los PDCCH.
- 13Un nodo de red (10) para un sistema de telecomunicación, en el que las asignaciones de los recursos de comunicaciones a los equipos de usuario se transmiten en una pluralidad de Canales de Control del Enlace Descendente Físicos, PDCCH, los PDCCH que están comprendidos en una zona de control de cada subtrama de enlace descendente, el nodo de red que se adapta para asignar los recursos de comunicaciones:dividiendo los PDCCH en al menos un subconjunto común de los PDCCH y una pluralidad de los subconjuntos de grupo de los PDCCH, que permiten a cada equipo de usuario descodificar el subconjunto común de los PDCCH y solamente un subconjunto de grupo de los PDCCH;en donde se determina un subconjunto de grupo respectivo de los PDCCH que va a ser descodificado por un equipo de usuario mediante el módulo de cuenta de un Identificador Temporal de Red Radio, RNTI, del equipo de usuario.
- 14Un nodo de red (10) como se reivindica en la reivindicación 13, en donde el subconjunto común de los PDCCH comprende los PDCCH del enlace descendente en el nivel de agregación más alto disponible.
- 15Un nodo de red (10) como se reivindica en la reivindicación 13 o 14, en donde cada subconjunto de grupo de los PDCCH comprende los PDCCH en uno o más niveles de agregación que cubren un subconjunto de elementos del canal de control.
- 16Un nodo de red (10) como se reivindica en la reivindicación 13, 14 o 15, adaptado además a:transmitir los mensajes de difusión en al menos un PDCCH que forma parte del subconjunto común de los PDCCH.
- 17Un nodo de red (10) como se reivindica en la reivindicación 13, 14, 15, o 16, adaptado además a:transmitir un mensaje de asignación de recursos para un equipo de usuario en al menos un PDCCH que forma parte del subconjunto común de los PDCCH.
- 18Un nodo de red (10) como se reivindica en una de las reivindicaciones 13 a 17, en donde el nodo de red (10) es un eNodoB de una Red de Acceso Radio Evolucionada.
- 19Un equipo de usuario (14) en un sistema de telecomunicación, en el que las asignaciones de los recursos de comunicaciones a los equipos de usuario (14, 16, 18) se transmiten en una pluralidad de Canales de Control del Enlace Descendente Físicos, PDCCH, los PDCCH que están comprendidos en una zona de control de cada subtrama del enlace descendente, el equipo de usuario (14) que se adapta para determinar los recursos de comunicaciones asignados al mismo por un método que comprende:determinar una división de los PDCCH en al menos un subconjunto común de los PDCCH y una pluralidad de subconjuntos de grupo de los PDCCH;determinar un subconjunto de grupo pertinente de los PDCCH a partir de la pluralidad de subconjuntos de grupo de los PDCCH;y descodificar los PDCCH que forman el subconjunto común de los PDCCH o cada subconjunto común de los PDCCH, y descodificar solamente los PDCCH del subconjunto de grupo pertinente de los PDCCH;y el equipo de usuario que se adapta además a determinar el subconjunto de grupo pertinente de los PDCCH mediante el módulo de cuenta de un Identificador Temporal de Red Radio, RNTI, del equipo de usuario (14).
- 20Un equipo de usuario (14) como se reivindica en la reivindicación 19, en donde en el paso de determinar la división de los PDCCH en al menos un subconjunto común de los PDCCH y una pluralidad de subconjuntos de grupo de los PDCCH comprende:determinar un número de elementos del canal de control en cada subtrama;y determinar a partir de dicho número de elementos del canal de control en cada subtrama si se ha hecho una división en dos o más subconjuntos de grupo de los PDCCH.
Independent claims20
70 paragraphs in 9 sections, as filed
ES 2 359 482 T3
DESCRIPTION
Method and adaptation in a telecommunication system.
FIELD OF THE INVENTION
This invention relates to a method and adaptation in a telecommunication system, and in particular to a method for assigning downlink control channels to user equipment.
BACKGROUND
Evolved UTRAN (E-UTRAN), sometimes also known as LTE (Long Term Evolution), is a new radio access technology being standardized by the 3-year Cooperation Project.<sup>S</sup> Generation (3GPP). Only the packet switched domain (PS) will be supported in E-UTRAN, that is, all services will be supported in the PS domain. The standard will be based on OFDM (Orthogonal Frequency Division Multiplexing) on the downlink and SC-FDMA (Single Carrier Frequency Domain Multiple Access) on the uplink.
In the time domain, a 1 ms long subframe is divided into 12 or 14 OFDM (or SC-FDMA) symbols, depending on the configuration. An OFDM (or SC-FDMA) symbol consists of a series of subcarriers in the frequency domain, depending on the configuration and bandwidth of the channel. An OFDM (or SC-FDMA) symbol on a subcarrier is known as a Resource Element (RE).
Dedicated data channels are not used in E-UTRAN; instead, shared channel resources are used on both the downlink and uplink. These shared resources, DL-SCH (Downlink Shared Channel) and UL-SCH (Uplink Shared Channel) are controlled by one or more schedulers who allocate different parts of the shared downlink and uplink channels to the UEs for the reception and transmission respectively.
The assignments for DL-SCH and UL-SCH are transmitted in a control area that covers a few OFDM symbols at the beginning of each downlink subframe. The DL-SCH is transmitted in a data area that covers the remaining OFDM symbols in each subframe of the downlink. The size of the control area is either one, two, three or four OFDM symbols and is set per subframe.
Each assignment for the DL-SCH or UL-SCH is transmitted on a physical channel called PDCCH (Physical Downlink Control Channel). There are multiple PDCCHs typically in each subframe and UEs will be required to monitor that the PDCCHs are capable of detecting the assignments addressed to them.
The groups of resource elements that can be used for the transmission of the control channels are known as Control Channel Elements (CCE), and a PDCCH is assigned to a series of CCEs. For example, a PDCCH consists of an aggregation of 1, 2, 4, or 8 CCEs. A PDCCH consisting of one CCE is known as an aggregation level 1 PDCCH, a PDCCH consisting of two CCEs is known as an aggregation level 2 PDCCH, and so on. Each CCE can only be used at one aggregation level at a time. The variable size achieved by the different levels of aggregation is used to adapt the coding speed to the level of the block error rate (BLER) required for each UE. The total number of CCEs available in a subframe will vary depending on various parameters, such as the number of OFDM symbols used for the control zone, the number of antennas, the system bandwidth, the size of the PHICH (HARQ Indicator Channel Physical), etc.
Each CCE consists of 36 RE. However, to achieve time and frequency diversity for PDCCHs, each CCE and its REs are spread, both in time over the OFDM symbols used for the control zone, and in frequency over the configured bandwidth. This is accomplished through a series of operations including interpolation, and cyclical shifts, etc. These operations are however predefined, and are fully known by the UEs. That is, each UE knows which resource elements make up each CCE, and is therefore capable of decoding the relevant resource elements to decode any desired PDCCH.
The existing system has the disadvantage that, since the UEs have no knowledge of where the PDCCHs specifically addressed to them are located, each UE has to decode the entire set of possible PDCCHs, ie the entire PDCCH space. The entire PDCCH space includes all CCEs at all aggregation levels. This would mean that considerable UE resources are consumed in decoding a large number of PDCCHs, of which only a few were actually addressed to them. This will use up the limited battery power of the UE and hence reduces the standby time of the UE.
Motorola's 3GPP Contribution Document R1-073373 describes a way to limit the scope of the search that a UE examines without sacrificing system performance. The CCEs of a control area can be formed into smaller sets of CCEs of maximum size K each where the sets are designated as candidate PDCCH search spaces with some amount of possible overlap between two search spaces.
ES 2 359 482 T3
Motorola's 3GPP contribution document R1-060378 proposes a control channel structure for the OFDMA downlink with the goal of minimizing control header oversizing while ensuring reliable decoding performance. The control information is divided into two parts dedicated and shared control. The dedicated control information is sent with the data at the beginning of the resource area assigned to the UE.
ABSTRACT
According to a first aspect of the present invention, there is provided a method of assigning communication resources in a telecommunication system, in which the assignments of communication resources to user equipments are transmitted on a plurality of Channels. Physical Downlink Control Panel, PDCCH. The PDCCHs are comprised in a control area of each downlink subframe. The downlink control channels, i.e. PDCCHs, are divided into at least one common subset of downlink control channels and a plurality of group subsets of downlink control channels, thereby allowing each team to decode the common subset and only a subset of the group. Additionally, the subset of the respective group of PDCCHs to be decoded by a user equipment is determined by the account module of a Radio Network Temporary Identifier, RNTI, of the user equipment.
According to a second aspect of the present invention, there is provided a method of operating a user equipment for determining the communications resources allocated to it in a telecommunication system, wherein the allocations of the communications resources to the equipment user data are transmitted on a plurality of Physical Downlink Control Channels, PDCCHs. The PDCCHs are comprised in a control area of each downlink subframe. A division of the PDCCHs into at least one common subset of the PDCCHs and a plurality of group subsets of the PDCCHs is determined, and a relevant group subset is determined from the plurality of group subsets. The PDCCHs that make up the common subset or each common subset of the PDCCHs are decoded, and only the PDCCHs of the relevant group subset of the downlink control channels are decoded. Additionally, the step of determining the relevant group subset of the PDCCHs comprises the counting module of a Radio Network Temporary Identifier, RNTI, of the user equipment.
According to a third aspect of the present invention, there is provided a network node for a telecommunication system, in which the assignments of the communication resources for the user equipments are transmitted on a plurality of Downlink Control Channels. Physicists, PDCCH. The PDCCHs are comprised in a control area of each downlink subframe. The network node divides the PDCCH into at least one common subset of the PDCCHs and a plurality of group subsets of the PDCCHs, allowing each user equipment to decode the common subset and only one group subset. Additionally, a respective group subset of the PDCCHs to be decoded by a user equipment is determined by the account module of a Radio Network Temporary Identifier, RNTI, of the user equipment.
According to a fourth aspect of the present invention, there is provided user equipment in a telecommunication system, in which the communications resource assignments for the user equipment are transmitted on a plurality of Downlink Control Channels. Physicists, PDCCH. The PDCCHs are comprised in a control area of each downlink subframe. The user equipment is adapted to determine the communications resources allocated to it by determining a division of the PDCCHs into at least a common subset of the downlink control channels and a plurality of the group subsets of the PDCCHs; and determining a relevant group subset from the plurality of group subsets. The user equipment is further adapted to decode the PDCCHs that form the common subset or each common subset of the downlink control channels, and decodes only the PDCCHs of the relevant group subset of the PDCCHs. Additionally, the user equipment is adapted to determine the relevant group subset of the PDCCHs by the account module of a Radio Network Temporary Identifier, RNTI, of the user equipment.
This has the advantage that the number of possible PDCCHs that have to be decoded by each UE is small. This is achieved by dividing the PDCCH space into a series of subsets where each UE only has to decode the PDCCHs from certain subsets.
A subset is defined as a specific set of possible PDCCHs. A common subset is a subset that all UEs will attempt to decode. A group subset is a subset that only a limited group of UEs will attempt to decode. The exact number of subsets of each type might differ. Also, as these subsets are formed with respect to the indices of the CCEs, and a level of aggregation of the CCEs in the PDCCHs, could differ.
A potential problem that could arise from introducing subsets of the control channels, and requiring each UE to decode only a subset is that some messages from the PDCCHs would be broadcast to all UEs in the cell, for example the SIB (Information Block System) sent on the BCCH (Broadcast Channel). To
In ES 2 359 482 T3 broadcast messages, the same DL-SCH allocation would have to be sent in each subset to reach all UEs. This would mean a waste of the resources of the PPAs.
Another problem with subsets is that the gain from pooling with a large set of SCCs is lost when resources are divided into a number of subsets. If all UEs are assigned to a subset during a subframe, the resources of CCEs in other subsets are lost and the system data flow could suffer.
However, according to the present invention, the disadvantage of the prior art is at least partially obviated, and these new potential disadvantages are not introduced. It is thus the basic idea of the present invention to reduce the number of PDCCHs that a UE has to decode without introducing severe restrictions leading to the problems described above. This is accomplished by dividing the entire set of possible PDCCHs into a series of group and common subsets respectively. Each group subset is decoded by a limited group of 0, 1 or more UEs, while the common subset, preferably there is only one, is decoded by each unique UE. The formation of the subsets is done in such a way that neither the resources of the CCEs have to be expended in case of diffusion nor that the CCEs are virtually lost for group subsets where the resources of the CCEs are not used.
The present invention therefore makes it possible to save the battery power of the UE without preventing the eNodeB from using the entire space of the CCEs. Furthermore, the invention allows efficient use of CCEs in case of broadcast messages.
Other objects, advantages, and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic diagram showing a representation of a part of a mobile communication network operating in accordance with one aspect of the present invention.
Figure 2 illustrates a possible division of a downlink subframe in time and frequency.
Figure 3 is a first flow chart, illustrating a method performed at a network node in accordance with one aspect of the present invention.
Figure 4 is a second flow chart, illustrating a method performed on user equipment in accordance with one aspect of the present invention.
Figure 5 is a schematic diagram, illustrating a division of the PDCCH space.
DETAILED DESCRIPTION
Figure 1 shows a part of a mobile communication network operating in accordance with one aspect of the present invention. This illustrated embodiment refers to a network operating in accordance with the Evolved UMTS Terrestrial Radio Access (E-UTRA) standards defined by the 3GPP organization. However, it will be appreciated that the invention can be applied to any network that involves allocation of shared resources on a system downlink.
Specifically, Figure 1 shows a base station, or eNodeB, 10 in a cell of a cellular network in the form of an Evolved Radio Access Network. In the illustrated embodiment of the invention, the network operates according to a standard based on OFDM (Orthogonal Frequency Division Multiplexing) on the downlink and SCFDMA (Single Carrier Frequency Domain Multiple Access) on the uplink. . Figure 1 also shows four UEs 12, 14, 16, 18 located within the cell served by the eNodeB 10.
Specifically, Figure 1 illustrates the general shape of the eNodeB 10. The eNodeB 10 has radio frequency (RF) interface circuitry 102, connected to an antenna 104, for transmitting and receiving signals over a wireless interface for UEs. Furthermore, there is a central network interface (CN) 106, to connect the eNodeB10 to the central network of the mobile communication network. Radio frequency interface circuitry 102 and core network interface 106 operate under the control of a processor 108. This is generally well understood, and will not be described further herein. In particular, processor 108 is responsible for allocating signals to available communication resources, which in this illustrative network comprise resources on particular frequency subcarriers during particular time periods. Processor 108 is also responsible for transmitting resource allocation messages to UEs. One aspect of such control is relevant to an understanding of the present invention, and is described in more detail below.
Figure 1 also illustrates the general shape of a UE 12, it being understood that the other UEs are generally similar. UE 12 has radio frequency interface circuitry 122, connected to an antenna 124, for transmitting and receiving signals over the wireless interface to eNodeB 10. Radio frequency interface circuitry 122 operates under the control of a processor 126. This is generally done understand well, and will not be described further here
ES 2 359 482 T3 inside. In particular, processor 126 is responsible for controlling RF interface circuitry 122, to ensure that intended signals are decoded, and that signals for transmission are applied to allocated communication resources.
Figure 2 illustrates the shape of a subframe. As is well known, a 1ms duration subframe is divided into 12 or 14 OFDM symbols (or SC-FDMA), depending on the configuration, and in this example the subframe is divided into 14 OFDM symbols. In the frequency domain, the available bandwidth is divided into subcarriers, depending on the configuration and the bandwidth of the channel. An OFDM (or SC-FDMA) symbol on a subcarrier is known as a Resource Element (RE). Certain predefined Resource Elements are used to transmit the reference symbols 20.
Shared channel resources are used on both the downlink and uplink, and these shared resources, DL-SCH (Downlink Shared Channel) and UL-SCH (Uplink Shared Channel), are each controlled by a scheduler that allocates different parts of the shared downlink and uplink channels to different UEs for reception and transmission respectively.
The assignments for the DL-SCH and UL-SCH are transmitted in a control area that covers a few OFDM symbols at the beginning of each downlink subframe. The size of the control area is either one, two, three or four OFDM symbols and is set per subframe. The size of the control area for a specific subframe is indicated by the Control Format Indicator (CFI) which is carried over the Physical Control Format Indicator Channel (PCFICH) in the first OFDM symbol of the same subframe. In the illustrated example shown in Figure 2, the control area covers the first three OFDM symbols in the subframe. The DLSCH is transmitted in a data area that covers the rest of the OFDM symbols in each subframe of the downlink. Thus, in this example, the data region covers the last eleven OFDM symbols in each subframe of the downlink.
Each assignment for the DL-SCH or UL-SCH is transmitted on a physical channel called PDCCH (Physical Downlink Control Channel). There are typically multiple PDCCHs in each subframe and UEs 12, 14, 16, 18 will be required to monitor the PDCCHs to be able to detect the assignments addressed to them.
A PDCCH is assigned to a series of CCEs (Control Channel Elements). A PDCCH consists of an aggregation of 1, 2, 4, or 8 CCEs. These four distinct alternatives are referred to herein as aggregation levels 1, 2, 4, and 8 respectively. Each CCE can only be used at one aggregation level at a time. The variable size achieved by the different levels of aggregation is used to adapt the encoding speed to the level of BLER required for each UE. The total number of CCEs available in a subframe will vary depending on various parameters, such as the number of OFDM symbols used for the control zone, the number of antennas, the system bandwidth, the size of the PHICH (Physical HARQ Indicator Channel ), etc.
Each CCE consists of 36 RE. However, to achieve time and frequency diversity for the PDCCHs, each CCE and its REs are spread, both in time over the OFDM symbols used for the control zone and in frequency over the configured bandwidth. This is accomplished through a series of operations including interpolation, and cyclical shifts, etc. These operations are however fully known to the UEs.
In the preferred embodiment of the invention, the PDCCH space can be divided, as will be described in more detail below.
Figure 3 is a flow chart, illustrating a process performed at the eNodeB, to determine whether to divide the PDCCH space into multiple group subsets. The advantage of dividing the PDCCH space into two or more group subsets is most notable when a large number of CCEs are available. This is for two reasons. First of all, it is mainly when there are a large number of SCCs that will be a capacity problem in the UE. That is, when there are a large number of CCEs, there are many combinations of CCEs that, with an undivided PDCCH space, would need to be decoded by the UE, placing a large load on the UE. Second, it is preferable to avoid resource fragmentation when there are few CCEs.
In this way, the process is advantageously carried out whenever the number of CCEs can change. At startup or reconfiguration the bandwidth, and hence the number of subcarriers in the system, could change, which is one of many parameters that determines the amount of CCE and hence the total amount of PDCCH. possible.
Furthermore, the size of the control area, that is, the number of OFDM symbols used for it, is also an important parameter in determining how many PDCCHs are possible in total. Since this could vary from one subframe to another, the PDCCH space division should also preferably vary on a subframe basis. This can be achieved by running the entire process once per subframe. Alternatively, if the number of possible splits other than the PDCCH space is not too large, the possible splits could be determined at eNodeB startup and then stored for all combinations of control area size and bandwidth, and any other relevant parameters.
ES 2 359 482 T3
In this way, in step 30 of the process illustrated in Figure 3, the number of available CCEs is determined and, in step 32, this number is compared with a threshold number. If the number of available CCEs does not exceed the threshold number, the process proceeds to step 34, in which it is determined that an undivided PDCCH space should be used. For example, the threshold number of CCEs, below which the undivided PDCCH space is used, for example can be set to about 10 or 15 CCEs. In this case, for example, each UE must decode every possible PDCCH. In step 35, the eNodeB is then able to transmit the PDCCHs to the UEs, for example containing the resource allocation messages, using this undivided PDCCH space.
If it is determined in step 32 that the number of available CCEs exceeds the threshold number, the process proceeds to step 36, in which it is determined that a divided PDCCH space should be used, as will be described in more detail below.
Following the division of the PDCCH space, the eNodeB will be able to transmit the PDCCHs, for example containing the resource allocation messages, to the UEs as shown in step 38, again as will be described in more detail below. .
Figure 4 is a flow chart, illustrating a process performed in a UE, preferably in each subframe, to determine which part of the PDCCH space to decode.
Thus, in step 50 of the process illustrated in Figure 3, the number of available CCEs is determined. Specifically, the UE should calculate the number of CCEs for each subframe. The number of CCEs in each subframe can be easily calculated from the PCFICH indicator, the configured bandwidth, the size and duration of the PHICH, the number of antennas, etc. All of these, except the PCFICH, are supposed to be semi-statically configured.
In step 52, the UE determines from the calculated number of CCEs in each subframe whether or not the group subsets are used. For example, as described above with reference to Figure 3, the number of CCEs in each subframe can be compared to a threshold number. This threshold number of course must be the same as the threshold number used by the eNodeB in step 32. The threshold number can be predefined, and stored in the eNodeB and UE, or it can be signaled from the eNodeB to the UE, for example in RRC signaling.
If the group subsets are not used, the process proceeds to step 54, in which it is determined that the UE should decode every possible PDCCH.
If it is determined in step 52 that the group subsets are being used, the process proceeds to step 56, where the UE determines which group subset to decode. More specifically, the UE should know by some implicit assignment or signaling which group subset to decode. There are several direct methods that could be used to achieve an implicit assignment. An example is the UE's Radio Network Temporary Identifier (RNTI) counting module to determine the initial location for the group subset. Of course, the UE must use the same method that was used in the eNodeB to assign the UEs to the group subsets.
In step 58, the UE decodes the PDCCHs in the relevant group subset determined in step 56, and in the common subset.
As mentioned above, when the number of available CCEs is above a threshold value, and it is decided to divide the PDCCH space, there are at least two group subsets. It may be advantageous for the number of group subsets that are used to grow beyond two with an increase in the total number of available CCEs, although the number of group subsets may not grow in direct proportion to the total number of available CCEs.
However, neither the details regarding the number of group subsets nor the details about how a UE is assigned to a certain group subset are essential to the invention.
Figure 5 shows the CCE resources available at a particular time, using the example. Thus, there are a number of CCEs, each having a respective CCE index, as shown alongside the horizontal axis in Figure 5. These CCEs can be combined with different levels of aggregation, as is known. Thus, Figure 5 shows the 70 CCEs with the lowest aggregation level of 1, but also shows the CCEs in 72 aggregations with an aggregation level of 2, in the 74 aggregations with an aggregation level of 4, and in aggregations 76 with the highest aggregation level of 8. As is known, the PDCCH space includes all CCEs at all aggregation levels.
According to an exemplary embodiment, a common subset is defined, in addition to the group subset mentioned above. This subset of the PDCCHs is then mandatory for all UEs to be decoded.
In the example shown in Figure 5, the common subset is defined to contain certain CCEs at a certain level of aggregation. The common subset can be advantageously formed to cover the PDCCH size plus
ES 2 359 482 T3 large possible, ie 8 CCE in the example shown in Figure 5. Defining the common subset as all possible PDCCHs at aggregation level 8, the entire CCE space can be more or less covered with a small PDCCH set, and thus all CCEs are enabled for use by any UE without forcing each UE to decode a large number of PDCCH candidates. By instead defining the common subset to include possible PDCCHs at the lower aggregation levels, more decodes would be required by the UE to cover a certain CCE space.
Group subsets can be formed for example to cover a certain set of CCE resources corresponding to certain CCE indices. The possible PDCCHs within each group subset are then defined by the possible aggregations on the PDCCHs from the CCE indices defined as resources for that group subset. All possible PDCCHs at all levels of aggregation (ie, 1, 2, 4, and 8) for all CCE indices in the group can then be defined to be part of that specific group subset.
In this way the common subset or each common subset will be decoded by each UE, and each group subset will be decoded only by a limited group of UEs.
In the example shown in Figure 5, a group subset is defined to cover all possible PDCCHs at all levels of aggregation (i.e. 1, 2, 4, and 8) for all CCE indices in the range from i1 to iN. This group subset therefore covers certain CCE indices, namely from the CCE index i1a iN, at each of the aggregation levels 1, 2, 4, and 8.
Alternatively, a group subset can be defined such that it contains the CCEs at one aggregation level that does not overlap with the CCEs at a different aggregation level. For example, a group subset can be defined to cover a first set of CCEs at aggregation level 8 that spans the first half of the interval from i1 to iN (that is, from i1 to i [N / 2] ) and a second set of SCCs at aggregation level 4 that extends over the upper half of the interval from i1 to iN (that is, from i [N / 2 + 1] to iN)
Thus, to avoid the need to send the PDCCHs for broadcast messages in all group subsets, a common subset is used for broadcast messages. Since, in the illustrated embodiment, the common subset includes the PDCCHs that contain the largest number of CCEs, these are well suited for broadcast messages that typically need to cover the entire cell. Using the common subset for broadcasting, enormous savings are achieved in terms of CCE resources, since the same allocation would otherwise have to be sent in many different group subsets and each of them probably occupies a large number of CCEs. to cover the cell.
The definition of the common subset allows messages to be assigned to PDCCHs in an efficient way. In the case where the majority of users at any given time are using the same group subset, then the more expensive PDCCHs, i.e. PDCCHs that contain many CCEs, can be moved to PDCCHs that are part of the subset common. By doing this, several smaller PDCCHs, that is, PDCCHs consisting of only a few CCEs, are made free. In this way unwanted skewed distributions, with respect to the number of users using the different subsets of the group, can be handled in an efficient way where the entire PDCCH resource can still potentially be used. For example, where a message, to be sent to a specific UE, requires many CCEs, that message can be sent on a PDCCH in the common subset. This will still ensure that the specific UE will decode the message, and will allow the PDCCHs in the group subset to be used to send smaller messages to the UEs that will decode that group subset.
To make the solution even more flexible, an optional update of PDCCHs occupying less CCE per PDCCH compared to PDCCHs in the common subset is introduced. This means that the number of CCEs per PDCCH can be increased to a level of aggregation above what is necessary to adapt to the link. As a result, PDCCHs, regardless of the required size in terms of number of CCEs, can be upgraded to an aggregation level corresponding to 8 CCEs (or whatever is the largest aggregation level set in the standard) for a PDCCH. Hence, any PDCCH, regardless of the level of aggregation required or which UE it is targeting, can potentially be moved to cover any CCE index.
For example, in the case where a group subset is defined in such a way that it contains the CCEs at an aggregation level that does not overlap with the CCEs at a different aggregation level, and in the situation where you want to transmit a PDCCH that requires a low aggregation level (for example aggregation level 2) but all possible PDCCHs at that low aggregation level are busy, then that PDCCH can be transmitted at a higher aggregation level (eg aggregation level 4) using different CCEs within the group subset.
There is thus disclosed a method for allocating communication resources.
The present invention may, of course, be carried out in other ways than those specifically set forth hereinafter without departing from the essential characteristics of the invention as defined in the
ES 2 359 482 T3 appended claims. The present embodiments are to be considered in all respects as illustrative and not restrictive.
Contents9
5 sheets
Sheet 1 Sheet 2 Sheet 3 Sheet 4 Sheet 5
63 members in 13 offices
Priority claims3
| Document | Office | Kind | Date |
|---|---|---|---|
| 1534707 | United States of America | P | |
| 1534707 | United States of America | P | |
| US20070015347P | – | – | – |
Members63
| Document | Office | Kind | |
|---|---|---|---|
| US2009161618A1 | United States of America | A1 | |
| CA2710155A1 | Canada | A1 | |
| CA3077668A1 | Canada | A1 | |
| CA3171892A1 | Canada | A1 | |
| WO2009082332A1 | World Intellectual Property Organization (WIPO) | A1 | |
| EP2208384A1 | European Patent Office (EPO) | A1 | |
| KR20100106504A | Republic of Korea | A | |
| CN101897227A | China | A | |
| EP2208384B1 | European Patent Office (EPO) | B1 | |
| AT495646T | Austria | T | |
| ATE495646T1 | Austria | T1 | |
| DE602008004574D1 | Germany | D1 | |
| JP2011508510A | Japan | A | |
| PT2208384E | Portugal | E | |
| ES2359482T3This record | Spain | T3 | |
| JP4988934B2 | Japan | B2 | |
| JP2012165452A | Japan | A | |
| DE202008018344U1 | Germany | U1 | |
| MY150312A | Malaysia | A | |
| US8837379B2 | United States of America | B2 | |
| JP5600136B2 | Japan | B2 | |
| JP2014239527A | Japan | A | |
| US2014376507A1 | United States of America | A1 | |
| CN101897227B | China | B | |
| CN105071910A | China | A | |
| KR101572856B1 | Republic of Korea | B1 | |
| KR20150139618A | Republic of Korea | A | |
| JP5865453B2 | Japan | B2 | |
| JP2016106462A | Japan | A | |
| KR101651195B1 | Republic of Korea | B1 | |
| KR20160102094A | Republic of Korea | A | |
| JP6022668B2 | Japan | B2 | |
| HK1217836A | Hong Kong, China | A | |
| HK1217836A1 | Hong Kong, China | A1 | |
| JP2017041895A | Japan | A | |
| KR101717156B1 | Republic of Korea | B1 | |
| KR20170031263A | Republic of Korea | A | |
| US9699782B2 | United States of America | B2 | |
| US2017280449A1 | United States of America | A1 | |
| KR101808671B1 | Republic of Korea | B1 | |
| KR20170140417A | Republic of Korea | A | |
| CN105071910B | China | B | |
| JP2018157581A | Japan | A | |
| KR20180108875A | Republic of Korea | A | |
| KR101930670B1 | Republic of Korea | B1 | |
| KR20190132583A | Republic of Korea | A | |
| JP6622169B2 | Japan | B2 | |
| JP6634472B2 | Japan | B2 | |
| JP2020058059A | Japan | A | |
| KR102167647B1 | Republic of Korea | B1 | |
| KR20200120764A | Republic of Korea | A | |
| KR102190849B1 | Republic of Korea | B1 | |
| JP6867468B2 | Japan | B2 | |
| JP2021119672A | Japan | A | |
| KR102301714B1 | Republic of Korea | B1 | |
| KR20210113440A | Republic of Korea | A | |
| US11432281B2 | United States of America | B2 | |
| KR102442447B1 | Republic of Korea | B1 | |
| KR20220129663A | Republic of Korea | A | |
| CA3077668C | Canada | C | |
| US2023055661A1 | United States of America | A1 | |
| JP7232860B2 | Japan | B2 | |
| CA2710155C | Canada | C |
Numbers
- Publication
- 2359482
- Publication, DOCDB
- 2359482
- Publication, EPODOC
- ES2359482T
- Application
- 8863667
- Application, DOCDB
- 08863667
- Application, EPODOC
- ES20080863667T
Titles2
- Spanish
- METODO Y APLICACION DE UN SISTEMA DE TELECOMUNICACION.
- English
- METHOD AND APPLICATION OF A TELECOMMUNICATION SYSTEM.
Classification
- CPC, 11
- H04L5/0037
- H04W72/23
- H04W72/0446
- H04L5/0053
- H04W48/12
- H04L1/0038
- H04L1/009
- H04L1/0091
- H04L5/0007
- H04W52/0222
- Y02D30/70
- IPC, 1
- H04W72 04