Channel state information reference signals
Abstract
A wireless communications method, comprising: identifying a plurality of resource elements, RE, of data available in a subframe; and assigning data RE from the plurality of data RE available for data transmission to a wireless device in groups of a predetermined number of RE, so that all data REs assigned within a group are within a predetermined number of respective symbols in the time domain, and within a second predetermined number of respective subcarriers in the frequency domain, characterized in that the plurality of available data REs comprise data REs not assigned to one of a channel status information reference signal RE, CSI-RS and a silenced CSI-RS RE, the predetermined number of symbols is zero, so that all data REs in a group are in the same OFDM symbol, the second default number of subcarriers is one or two, the pool is limited to data RE within the same resource block, the predetermined number of data REs depends on the number of transmission antenna ports used for the transmission of a common reference signal, CRS, and the groups of the predetermined number of data REs comprise pairs of space-frequency block code, SFBC, or space-time block code transmitted using an Alamouti transmission diversity scheme.
Term
4.4 yearsto projected expiry
Projected expiry 23 February 2031, counted from filing; an application has no term until it is granted.
- Priority
- Filed
- Published
- Today
- Projected expiry
13 claims: 4 independent, 9 dependent
- 1ES 2 586 666 T3 REIVINDICACIONES 1. Un procedimiento de comunicaciones inalámbricas, que comprende:identificar una pluralidad de elementos de recurso, RE, de datos disponibles en una subtrama;y asignar RE de datos de la pluralidad de RE de datos disponibles para la transmisión de datos a un dispositivo inalámbrico en grupos de un número predeterminado de RE, de modo que todos los RE de datos asignados dentro de un grupo están dentro de un número predeterminado de símbolos respectivos en el dominio de tiempo, y dentro de un segundo número predeterminado de subportadoras respectivas en el dominio de frecuencia, caracterizado porque la pluralidad de RE de datos disponibles comprenden RE de datos no asignados a uno de entre un RE de señal de referencia de información de estado de canal, CSI-RS y un RE de CSI-RS silenciado, el número predeterminado de símbolos es cero, de modo que todos los RE de datos de un grupo están en un mismo símbolo OFDM, el segundo número predeterminado de subportadoras es de uno o dos, la agrupación está limitada a RE de datos dentro del mismo bloque de recursos, el número predeterminado de RE de datos depende del número de puertos de antena de transmisión usados para la transmisión de una señal de referencia común, CRS, y los grupos del número predeterminado de RE de datos comprenden parejas de código de bloque de espacio-frecuencia, SFBC, o de código de bloque de espacio-tiempo transmitidas usando un esquema de diversidad de transmisión de Alamouti.
- 2El procedimiento según la reivindicación 1, en el que la asignación de RE de la pluralidad de RE de datos disponibles para la transmisión de datos da como resultado al menos un RE no agrupado.
- 3El procedimiento según la reivindicación 2, que comprende además asignar el al menos un RE no agrupado a otras transmisiones hacia otros dispositivos inalámbricos.
- 4El procedimiento según la reivindicación 2, que comprende además usar el al menos un RE no agrupado para una transmisión que no es de datos hacia el dispositivo inalámbrico.
- 5El procedimiento según la reivindicación 2, que comprende además impedir el uso del al menos un RE no agrupado en las transmisiones.
- 6El procedimiento según la reivindicación 5, que comprende además silenciar las transmisiones de CSI-RS en un patrón de silenciamiento predeterminado.
- 7El procedimiento según la reivindicación 2, que comprende además usar el al menos un RE no agrupado para la transmisión al dispositivo inalámbrico usando un esquema de transmisión diferente al uso para las transmisiones de datos hacia el dispositivo inalámbrico en los RE agrupados.
- 8Un aparato de comunicaciones inalámbricas, que comprende:medios para identificar una pluralidad de elementos de recurso (RE) de datos disponibles en una subtrama;y medios para asignar RE de datos de la pluralidad de RE de datos disponibles para la transmisión de datos a un dispositivo inalámbrico en grupos de un número predeterminado de RE, de modo que todos los RE de datos asignados dentro de un grupo están dentro de un número predeterminado de símbolos respectivos en el dominio de tiempo, y dentro de un segundo número predeterminado de subportadoras respectivas en el dominio de frecuencia, caracterizado porque la pluralidad de RE de datos disponibles comprenden RE de datos no asignados a uno de entre un RE de señal de referencia de información de estado de canal, CSI-RS y un RE de CSI-RS silenciado, el número predeterminado de símbolos es cero, de modo que todos los RE de datos de un grupo están en un mismo símbolo OFDM, el segundo número predeterminado de subportadoras es de uno o dos, la agrupación está limitada a RE de datos dentro del mismo bloque de recursos, el número predeterminado de RE de datos depende del número de puertos de antena de transmisión usados para la transmisión de una señal de referencia común, CRS, y los grupos del número predeterminado de RE de datos comprenden parejas de código de bloque de espacio-frecuencia, SFBC, o de código de bloque de espacio-tiempo transmitidas usando un esquema de diversidad de transmisión de Alamouti.
- 9Un procedimiento de comunicaciones inalámbricas, que comprende:recibir una señal de referencia en una subtrama de RE asignados a transmisiones de la señal de referencia, donde la subtrama comprende una pluralidad de RE de datos restantes;y recibir datos de al menos uno de la pluralidad de RE de datos restantes, donde los datos se transmiten en grupos de un número predeterminado de RE, de modo que todos los RE de datos asignados dentro de un ES 2 586 666 T3 grupo están dentro de un número predeterminado de símbolos en el dominio de tiempo y de un segundo número predeterminado de subportadoras respectivas en el dominio de frecuencia, caracterizado porque la pluralidad de RE de datos disponibles comprenden RE de datos no asignados a uno de entre un RE de señal de referencia de información de estado de canal, CSI-RS y un RE de CSI-RS silenciado, el número predeterminado de símbolos es cero, de modo que todos los RE de datos de un grupo están en un mismo símbolo OFDM, el segundo número predeterminado de subportadoras es de uno o dos, la agrupación está limitada a RE de datos dentro del mismo bloque de recursos, el número predeterminado de RE de datos depende del número de puertos de antena de transmisión usados para la transmisión de una señal de referencia común, CRS, y los grupos del número predeterminado de RE de datos comprenden parejas de código de bloque de espacio-frecuencia, SFBC, o de código de bloque de espacio-tiempo transmitidas usando un esquema de diversidad de transmisión de Alamouti.
- 10El procedimiento según la reivindicación 9, en el que la señal de referencia comprende una señal de referencia de información de estado de canal (CSI-RS).
- 11El procedimiento según la reivindicación 9, en el que los grupos del número predeterminado de RE comprenden parejas de código de bloque de espacio-frecuencia (SFBC) o de código de bloque de espaciotiempo.
- 12Un aparato de comunicaciones inalámbricas, que comprende:medios para recibir una señal de referencia en una subtrama de RE asignados a transmisiones de la señal de referencia, donde la subtrama comprende una pluralidad de RE de datos restantes;y medios para recibir datos de al menos uno de la pluralidad de RE de datos restantes, donde los datos se transmiten en grupos de un número predeterminado de RE, de modo que todos los RE de datos asignados dentro de un grupo están dentro de un número predeterminado de símbolos en el dominio de tiempo y de un segundo número predeterminado de subportadoras respectivas en el dominio de frecuencia, caracterizado porque la pluralidad de RE de datos disponibles comprenden RE de datos no asignados a uno de entre un RE de señal de referencia de información de estado de canal, CSI-RS, y un RE de CSI-RS silenciado, el número predeterminado de símbolos es cero, de modo que todos los RE de datos de un grupo están en un mismo símbolo OFDM, el segundo número predeterminado de subportadoras es de uno o dos, la agrupación está limitada a RE de datos dentro del mismo bloque de recursos, el número predeterminado de RE de datos depende del número de puertos de antena de transmisión usados para la transmisión de una señal de referencia común, CRS, y los grupos del número predeterminado de RE de datos comprenden parejas de código de bloque de espacio-frecuencia, SFBC, o de código de bloque de espacio-tiempo transmitidas usando un esquema de diversidad de transmisión de Alamouti.
- 13Un producto de programa informático que comprende un medio legible por ordenador que tiene instrucciones que hacen que al menos un ordenador lleve a cabo uno cualquiera de los procedimientos según la reivindicación 1 a 7 ó 9 a 11 cuando se ejecutan.
Independent claims13
231 paragraphs in 12 sections, as filed
ES 2 586 666 T3
DESCRIPTION
Channel status information reference signals
CROSS REFERENCE WITH RELATED REQUESTS
This application claims the priority benefit of US Provisional Patent Application Serial No. 61 / 307,413, entitled "CHANNEL STATE INFORMATION REFERENCE SIGNALS," filed February 23, 2010, US Provisional Patent Application Serial No. Series 61 / 307,758, entitled "CHANNEL STATE INFORMATION REFERENCE SIGNALS," filed February 24, 2010, US Provisional Patent Application Serial No. 61 / 374,556, titled “CHANNEL STATE INFORMATION REFERENCE SIGNALS,” filed August 17, 2010, and US Provisional Patent Application Serial No. 61 / 438,183, titled “CHANNEL STATE INFORMATION REFERENCE SIGNALS,” filed January 31, 2011.
BACKGROUND
I. Field
The following description relates generally to wireless communications and more particularly to the use of channel status information reference signals in a wireless communications system.
II. Background
Wireless communication systems are widely used to provide various types of communication content, such as voice, data, etc. These systems can be multiple access systems capable of supporting communication with multiple users by sharing available system resources (eg bandwidth and transmission power). Examples of such multiple access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, long-term evolution systems (LTE) from 3GPP, and Orthogonal Frequency Division Multiple Access (OFDMA) systems.
In general, a multiple access wireless communication system can simultaneously support communications for multiple wireless terminals. Each terminal communicates with one or more base stations through transmissions on the forward link and on the reverse link. Forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link can be established through a single-input single-output system, a multiple-input single-output system, or a multiple-input, multiple-output (MIMO) system.
A MIMO system uses multiple (Nt) transmit antennas and multiple (Nr) receive antennas for data transmission. A MIMO channel formed by the Nt transmitting antennas and the Nr receiving antennas can be decomposed into Ns independent channels, which are also called spatial channels, where Ns min {Nt, Nr}. Each of the Ns independent channels corresponds to a dimension. The MIMO system can provide improved performance (eg higher throughput and / or higher reliability) by utilizing the additional dimensions created by multiple transmit and receive antennas.
In addition, a base station or a mobile terminal can transmit reference signals to maintain or improve the performance of the wireless system. Reference signals are normally signals known a priori by a receiver. A receiving device can receive reference signals and, based on the received reference signals, can modify certain operating parameters or generate response information to modify certain operating parameters of the wireless communication. Although the reference signals can be useful, the transmission of the reference signals can occupy the bandwidth of other useful signals, such as data or control signals. With the increasing demand for wireless data bandwidth, there is a greater demand for the efficient use of existing reference signals. Furthermore, the allocation of transmission resources to new reference signals can possibly reduce the transmission resources available for pre-existing reference signals or data signals. Furthermore, the new reference signals can be transmitted using transmission resources, where the legacy user equipment may be waiting for data transmissions.
3GPP TSG RAN WG1 56 bis, R1-091292, “Multiplexing and Signaling Support for Downline COMP” (Texas Instrument, Seoul, March 23-27, 2009) deals with multiplexing between LTE version 8 transmissions and COMP DL transmissions. LTE-A.
RESUME
The systems and procedures provided in this disclosure meet the needs described.
ES 2 586 666 T3 above, in addition to others. Briefly and generally speaking, the disclosed designs, in one aspect, provide methods and apparatus for using muted resource elements and channel status information reference signals (CSI-RS) in a wireless communication network. .
A summary of one or more embodiments is provided below in order to provide a basic understanding of such techniques and embodiments. This summary is not a comprehensive overview of all contemplated embodiments and is not intended to identify key or critical elements of all embodiments or to delineate the scope of some or all of the embodiments. Its sole purpose is to present some concepts of one or more embodiments in a simplified manner as a prelude to the more detailed description that will be presented later.
In one aspect, a wireless communications method comprises identifying a plurality of data resource elements (REs) available in a subframe and assigning the REs of the plurality of data REs available for data transmission to a wireless device in groups of a predetermined number of REs, such that all assigned data REs within a group are within a predetermined number of respective symbols in the time domain, and within a second predetermined number of respective subcarriers in the frequency domain, thus resulting in at least one unused RE.
In another aspect, a wireless communications apparatus comprises means for identifying a plurality of data resource elements (REs) available in a subframe and means for assigning the REs of the plurality of data REs available for data transmission to a device. wireless in groups of a first predetermined number of RE, such that all data REs allocated within a group are within a predetermined number of respective symbols in the time domain, and within a second predetermined number of respective subcarriers in the frequency domain, thus resulting in the minus one non-clustered RE.
In yet another aspect, a computer program product is disclosed comprising a non-volatile computer-readable medium that stores computer-executable instructions. The instructions comprise code for identifying a plurality of data resource elements (REs) available in a subframe and for assigning the REs of the plurality of data REs available for data transmission to a wireless device in groups of a first predetermined number. of RE, so that all data REs allocated within a group are within a predetermined number of respective symbols in the time domain, and within a second predetermined number of respective subcarriers in the frequency domain, thus resulting in at least one non-clustered RE.
In another aspect, a wireless communication processor is disclosed. The wireless processor is configured to identify a plurality of data resource elements (REs) available in a subframe and to assign the REs of the plurality of data REs available for data transmission to a wireless device in groups of a first number. predetermined RE so that all assigned data REs within a group are within a predetermined number of respective symbols in the time domain, and within a second predetermined number of respective subcarriers in the frequency domain, thus resulting in at least one non-clustered RE.
To achieve the above and related objectives, one or more aspects comprise the features described in greater detail below and set forth particularly in the claims. The following description and accompanying drawings set forth certain illustrative aspects in detail and only indicate some of the various ways in which the aspects principles may be used. Other advantages and novel features will become apparent from the following detailed description when considered in conjunction with the drawings, and the disclosed aspects are intended to include all such aspects and their equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
The features, nature and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which the same reference characters identify the same components, and in which:
FIG. 1 illustrates a multiple access wireless communication system according to one embodiment.
FIG. 2 illustrates a block diagram of a communication system.
FIG. 3 is a block diagram representation of a resource block used in a wireless communication system.
FIG. 4A is a block diagram representation of two adjacent resource blocks used in a wireless communication system.
FIG. 4B is a block diagram representation of a resource block used in a system
ES 2 586 666 T3 of wireless communications.
FIG. 4C is a block diagram representation of a resource block used in a wireless communication system.
FIG. 5 is a block diagram representation of a resource pattern used in a wireless communication system comprising 2 channel status information reference signal (CSI-RS) ports.
FIG. 6 is a representation in block diagram form of a resource block used in a wireless communication system comprising 4 channel status information reference signal ports (CSI-RS).
FIG. 7 is a block diagram representation of a resource block used in a wireless communication system comprising 8 channel status information reference signal (CSI-RS) ports.
FIG. 8 is a block diagram representation of a resource block used in a wireless communication system.
FIG. 9 is a representation in block diagram form of a resource block used in a wireless communication system.
FIG. 10 is a block diagram representation of a resource block used in a wireless communication system.
FIG. 11 is a block diagram representation of a resource block used in a wireless communication system.
FIG. 12 is a block diagram representation of a resource block used in a wireless communication system.
FIG. 13 is a representation in block diagram form of schemes for assigning resource element pairs to frequency space block code (SFBC) pairs.
FIG. 14 is a representation in block diagram form of schemes for assigning resource element pairs to frequency space block code (SFBC) pairs.
FIG. 15 is a block diagram representation of a resource pattern assignment in a wireless communication system.
FIG. 16 is a block diagram representation of a resource pattern assignment in a wireless communication system.
FIG. 17 is a block diagram representation of a resource pattern assignment in a wireless communication system.
FIG. 18 is a block diagram representation of a resource pattern assignment in a wireless communication system.
FIG. 19 is a block diagram representation of a resource pattern assignment in a wireless communication system.
FIG. 20 is a block diagram representation of a resource pattern assignment in a wireless communication system.
FIG. 21 is a flowchart representation of a wireless communication process.
FIG. 22 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 23 is a flowchart representation of a wireless communication process.
FIG. 24 is a block diagram representation of a part of a wireless communication apparatus.
ES 2 586 666 T3
FIG. 25 is a flowchart representation of a wireless communication process.
FIG. 26 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 27 is a flowchart representation of a wireless communication process.
FIG. 28 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 29 is a flowchart representation of a wireless communication process.
FIG. 30 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 31 is a flowchart representation of a wireless communication process.
FIG. 32 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 33 is a flowchart representation of a wireless communication process.
FIG. 34 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 35 is a flowchart representation of a wireless communication process.
FIG. 36 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 37 is a flowchart representation of a wireless communication process.
FIG. 38 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 39 is a flowchart representation of a wireless communication process.
FIG. 40 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 41 is a flowchart representation of a wireless communication process.
FIG. 42 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 43 is a flowchart representation of a wireless communication process.
FIG. 44 is a block diagram representation of a part of a wireless communication apparatus.
FIG. 45 is a flowchart representation of a wireless communication process.
FIG. 46 is a block diagram representation of a part of a wireless communication apparatus.
Various aspects will now be described with reference to the drawings. In the following description, numerous specific details are set forth for explanatory purposes in order to provide a thorough understanding of one or more aspects. However, it may be apparent that the various aspects can be implemented without these specific details. In other cases, widely known structures and devices are shown in block diagram form in order to facilitate the description of these aspects.
The techniques described herein can be used in various wireless communication networks, such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access networks. (FDMA), orthogonal FDMA networks (OFDMA), single carrier FDMA networks (SC-FDMA), etc. The terms "networks" and "systems" are normally used interchangeably. A CDMA network can implement radio technology, such as Radio Access
ES 2 586 666 T3
Universal Terrestrial (UTRA), cdma2000, etc. UTRA includes Broadband CDMA (W-CDMA) and Low Chip Speed (LCR). cdma2000 covers the IS-2000, IS-95 and IS-856 standards. A TDMA network can implement radio technology such as the Global System for Mobile Communications (GSM). An OFDMA network can implement a radio technology such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, Flash-OFDMD, etc. UTRA, E-UTRA and GSM are part of the Universal Mobile Telecommunications System (UMTS). Long Term Evolution (LTE) is a release version of UMTS that uses E-UTRA. UTRA, EUTRA, GSM, UMTS, and LTE are described in documents from an organization called the Third Generation Partnership Project (3GPP). cdma2000 is described in documents from an organization called Third Generation Partnership Project 2 (3GPP2). These various radio standards and technologies are known in the art. For clarity, certain aspects of the techniques are described below for LTE, with LTE terminology used throughout much of the following description.
Single carrier frequency division multiple access (SC-FDMA) uses single carrier modulation and equalization in the frequency domain. An SC-FDMA signal has a lower peak power to average power ratio (PAPR) due to its intrinsic single carrier structure, which can greatly benefit the mobile terminal in terms of transmit power efficiency. It is currently used in the uplink multiple access scheme in the Long Term Evolution (LTE) of 3GPP.
It should be noted that, for clarity, the following content is described with respect to specific examples of certain signals and message formats used in LTE and with respect to channel status information reference signal and squelch technology (CSI-RS ). However, those skilled in the art will appreciate the application of the disclosed techniques to other communication systems and other reference signal transmission / reception technologies.
In addition, various combinations of antenna ports and transmission resource assignments are described in FIGS. 3-13 using a resource block mapping technique, where a two-dimensional graph of available resources in a transmit resource block (RB) is illustrated with symbols (or time) in the horizontal direction and with frequency (or subcarrier index ) in the vertical direction. Also, for clarity, the Resource Elements (RE) in each illustrated RB are labeled with a corresponding antenna port / antenna index group, which simply represents a logical grouping of antennas. However, it should be understood that the enumeration using an alphabetical sequence and numbers is only intended to facilitate explanation, and may or may not correspond to an actual antenna arrangement of a device.
CSI-RSs are signals transmitted by an eNB to allow a UE to estimate the DL channel and send response information about the channel to the eNB. It is planned to introduce CSI-RS in LTE-A to be used as response information to support SU-MIMO, MU-MIMO and CoMP. Since LTE version 8 UEs (legacy UEs) do not detect CSI-RSs, they continue to act as if they are not present, making it difficult to introduce CSIRS. It is planned to include CSI-RS in the PDSCH region. There are some additional restrictions on where to include CSI-RS.
In some designs, the transmission resources allocated to CSI-RSs may avoid REs allocated to other reference signals, such as common reference signals (CRS). Also, in some designs, the entire symbol to which CRS REs are assigned can be avoided for CSI-RSs. This avoidance of CRS symbols by CSI-RSs can be helpful in minimizing interference from CRS transmissions to CSI-RS transmissions. For example, if the CRS and CSI-RSs of a cell are in the same symbol, increasing the power of the CRS could reduce the power of the CSI-RS, and the CRS of neighboring cells could collide with the CSI- RS in synchronous networks, which could make the channel estimation from CSI-RS unreliable in a given cell. In some designs, CSI-RS assignments via two transmit antennas (2Tx) can also avoid CRS symbols for all REs from four transmit antennas (4Tx) since neighboring cells may be using 4 transmit antennas.
Also, in some designs, CSI-RSs can avoid the first three OFDM symbols in a resource block (RB) since the first three symbols can be used for the transmission of control signals (control symbols). Avoiding control symbols can also be useful in relay operations as a relay node may need to transmit and receive CSI-RS. In relay designs where a relay advertises its backlink DL subframes as MBSFNs to its UE 120s, the relay may not be able to detect the first (one to three) OFDM symbols.
In some transmission modes, UE-specific reference signals (UE-RS), also called demodulation reference signals (DM-RS) can be transmitted over an eNB 110 to the UE 120 to help the UE 120 estimate the channel for the data demodulation. In some designs, the CSI-RS pattern may not depend on whether the UE-RS based transmissions are scheduled or not. Therefore, in some designs, REs assigned to CSI-RSs may be selected to avoid UE-RSs. As used herein, assigning REs to CSI-RS transmissions involves designating certain REs as available for reference signal transmissions. As explained in detail below, designated REs may or may not be used in actual reference signal transmissions, depending on other considerations, such as the
ES 2 586 666 T3 silencing. In some designs, CSI-RSs are assigned transmission resources avoiding overlap with REs assigned to other signals, such as CRS and UE-RS. As a result, in some designs, a total of 60 RE ports may be available in subframes that do not contain the REs assigned to other reference or control signals (eg, in a normal subframe with a normal CP). Also, in some designs, CSI-RSs can avoid collision with sync signals and with PBCH and SIB. In some designs, as explained in more detail later, CSI-RS RE assignment may also avoid overlap with paging channels of legacy UEs 120.
FIG. 3 is a block diagram representation of a resource block 300 used in a wireless communication system. Horizontal axis 302 represents time (or a symbol index) and vertical axis 304 represents frequency. Each square represents a resource element (RE), which represents a time-frequency transmission resource quantum. REs designated with the letter C (eg, RE 306) may represent REs assigned to CRS transmissions. REs designated with the letter U (eg, RE 308) may represent REs assigned to UE-RS transmissions. REs numbered 1 through 60 (for example, RE 310s) may correspond to REs available for CSI-RS broadcasts. In a given cell, the eNB 110 may select a subset from all possible REs and assign the REs from the selected subset to the CSI-RS transmission in that cell. The remaining REs can be used for data transmissions, as described in detail below.
In some designs, CSI-RS transmissions can be used as a common pilot transmission for multiple UE 120s. Since response information for the entire bandwidth occupied by a wireless channel may be desirable, CSI-RSs can be transmitted normally. across a wide bandwidth in the subframes where CSI-RSs are present. In multi-antenna systems, CSI-RSs can be transmitted to allow independent channel estimation of all transmitting antennas. In various designs, CSI-RS transmissions from different antenna ports can be time domain, frequency domain, and / or code domain multiplexed. For example, in a combined time / frequency domain multiplexing design, the REs assigned to CSI-RS transmissions from different antenna ports may comprise different RE patterns. However, in some designs, all CSI-RS transmissions (for all antennas) in a cell may be assigned a transmission resource in the same subframe, so that from the perspective of a UE 120, the channel estimate for all antenna ports it can be carried out by receiving CSI-RS transmissions during the used subframe. Such selective CSI-RS processing from the same subframe can help manage power (eg, the UE 120 does not have to stay on to receive multiple subframes of CSI-RS transmissions).
In some wireless systems, such as cooperative multipoint networks (CoMP) or heterogeneous networks (HetNet), the eNB 110 may want the UE 120 to measure neighboring cell channels. In such designs, the CSI-RS transmissions of some cells can be orthogonalized (eg, use a different set of REs). For example, in some designs, an eNB 110 may inhibit REs (eg, silence them or carry out no transmission over them) assigned to CSI-RS transmissions in a neighboring cell. The assigned RE patterns of different neighboring cells can be coordinated with each other by eNB 110s.
In some designs, the CSI-RS REs assigned to a particular transmit antenna port can be chosen so that the entire channel bandwidth is uniformly sampled by the REs assigned to the transmit antenna port. Due to time variations in channel characteristics, it may be desirable for all CSI-RS REs on a particular antenna port to be close to each other or on the same OFDM symbol. For example, in some designs, the REs designated 1, 7, 19, 23, 25, 31, 55, and 59 in FIG. 3 can be used on 8 different antenna ports, thus providing a repeating pattern on each RB that is evenly spaced across the frequency band.
In some designs, the transmission resources can be allocated for CSI-RS transmission to the antenna in the OFDM symbols where the CSI-RS is transmitted, so that full power can be used. For example, since CSI-RSs can be transmitted normally in a given time only from a single antenna port, the power allocated to other antenna ports may not be used. However, if multiple CSI-RS antenna port REs are mapped into an OFDM symbol, the CSI-RS of an active antenna port (that is, the antenna port that actually transmits the signal) can also use the power assigned to that antenna port that is not being used in an actual signal transmission.
A legacy UE 120 (such as a version 8 UE 120 in a version 10 network) cannot detect CSI-RS transmissions and can assume that all data is being transmitted on REs assigned to the CSI-RS. In some designs, the legacy UE 120 can assume that the data transmissions use space-frequency block coding (SFBC) when 2 CRS ports are configured, and SFBC-FSTD when 4 CRS antenna ports are configured. In some designs, the SFBC scheme and the SFBC frequency shift and time diversity scheme (FSTD) may comprise transmitting 2 data symbols in 2 frequency-contiguous data REs (omitting any intervening CRS REs) using the Alamouti. To minimize the impact of CSI-RS culling in the planned EU 120 using these schemes, the number of ER pairs involved in the Alamouti scheme that are affected by culling
ES 2 586 666 T3 can be minimized. As explained in detail below, instead of selectively removing 2 ERs in two different ER pairs, both ERs from a pair can be selectively removed.
In some designs, the SFBC-FSTD scheme can use SFBC using antenna ports 0, 2 on the first 2 data REs, and antenna ports 1, 3 on the next 2 data REs in a given group of four REs. of data. The term "data RE" generally refers to a resource element considered by a legacy UE 120 to be available for data transmission. However, depending on the allocation of the reference signal transmission resources and the squelch, a data RE may, in some cases, be used for the transmission of other signals, or it may not be used at all for the transmissions. In some designs, the two REs used in SFBC can be selected to be close to each other so that the channel estimates of the two REs are nearly identical. In some designs, planned version 10 UE 120s using such a scheme may use frequency contiguous data REs (omitting any intermediary CSIRE REs and CRS REs). Correlation can be performed in groups of 4 RE in frequency for SFBCFSTD (2 RE in frequency for SFBC). In case the number of available data REs is not a multiple of 4, for example when it is 4n + 2, FSTD can be used n times, and for the remaining two REs SFBC using two antenna ports can be used. This can introduce a power imbalance. It may be desirable to enter CSI-RS so that the number of data REs available in each symbol of an RB can be a multiple of 4 for 4 CRS (and 2 for 2 CRS) when scheduling using this mode.
When the number of REs of available data (by RB or alternatively by data allocation) follows the form 4n + 2 for SFBC-FSTD (or 2n + 1 for SFBC) in two neighboring symbols (where n is an integer) , SFBC / SFBC-FSTD can be used in combination with STBC, where the Alamouti scheme is applied over time. This allows all available REs to be used while maintaining balanced power.
FIG. 4A is a block diagram representation 400 of two adjacent resource blocks showing REs assigned to CSI-RS, in some designs. The assigned REs are labeled using a combination of two alphabet characters (a, b, c, dof) that represent a group of antenna ports, and a number (1 to 8) that represent an antenna port index. An eNB 110 with eight transmit antenna ports (8Tx) can select one of the groups a to f and can use the remaining CSI-RS REs for data transmissions. The RE assignment pattern illustrated in FIG. 4B allows orthogonal multiplexing of 6 different eNB 110s with 8 transmit antennas each (where each eNB 110 uses one of the six groups a to f). The design assumes that a resource density of 1 RE / RB is used for the CSI-RS.
It should be noted that in OFDM symbols containing a user equipment reference signal, or UE-RS, (eg symbols 450, 452), 6 RE may be available (instead of 8) for CSIRS transmissions . In some designs, to allow 8 CSI-RS antenna ports, antenna ports 1 to 4 can be assigned to a first OFDM symbol (eg 450 symbol) of a pair of OFDM symbols (eg 450, 452) containing UE-RS, and antenna ports 5 through 8 may have REs assigned in the next adjacent OFDM symbol (eg, symbol 452). To allow full power operation, the mapping of the antenna ports for symbols 450, 452 can be modified in the next RB so that all ports are arranged within the same symbol location in the neighboring RB. Neighboring symbols may be chosen in some design for the allocation of CSI-RS resources to the same group of antennas to advantageously use the fact that the time variation in channel characteristics between adjacent symbols can be relatively small.
In some designs, the 4Tx 110 eNBs can choose the CSI-RS ports {1,2,3,4} or {5,6,7,8} from a group of antennas a to f. In some designs, 2Tx 110 eNBs can choose RE pairs {1,2}, {3,4}, {5,6}, {7,8} in a group, for CSI-RS transmission. Therefore, the antenna port assignment can be chosen such that even with a smaller number of CSI-RS antenna ports, all OFDM symbols containing the CSI-RS REs of a particular eNB 110 have CSI-RS REs. RS corresponding to all antenna ports. In one aspect, such an assignment of REs to antenna ports facilitates orthogonal multiplexing of eNBs 110 with different antenna configurations.
Referring now to FIG. 4C another resource block 480 is shown for assigning a resource pattern to 4 CSI-RS ports for eNB 4Tx 110. In some designs, the pattern illustrated in FIG. 4C can be repeated for each Rb in which a CSI-RS is assigned. It can be seen that the 4Tx assignment is included in an 8Tx assignment by dividing the 8Tx assignments illustrated in FIG. 4B in two groups of 4Tx. 4Tx assignments can be further divided into RE assignments for eNB 2Tx 110.
It should be appreciated that in the illustrated RE assignment of FIG. 4C, the CSI-RS REs have been chosen to selectively remove both data REs in an SFBC pair for the legacy UEs 120. For example, if the CSI-RS assignment pattern were to vertically descend one RE location in DM-RS symbols 482, 484, two REs from different SFBC pairs would be selectively removed.
Typically, the number of CSI-RS ports is greater than or equal to the number of CRS ports. It can also be appreciated that when the CRS number is 4, the CSI-RS port assignment could be for 4 or 8 antenna ports, and the
ES 2 586 666 T3 number of REs used by CSI-RSs in any symbol can be 0, 4 or 8. In one aspect, such an assignment can ensure that a multiple of 4 REs are reassigned to the CSI-RS from the RE data is available and therefore no RE is left ungrouped (ie, there are no orphaned REs). Also, when the number of CRS is 2, the number of CSI-RS antenna ports can be (2, 4, 8). In such a case, the REs of CSI-RS in any symbol can be 0, 2, 4 or 8, ensuring that there are no orphan REs if SFBC is used. In some designs where the location of antenna ports 3 and 4 is swapped with that of antenna ports 5, 6, the property of no orphaned REs cannot be met. It should be noted that some REs that may have been used for CSI-RSs may be left unused for CSI-RSs to retain this non-orphan data RE property.
Referring to FIG. 4C, a block diagram representation of a resource block 480 is illustrated, showing another exemplary assignment of RE to CSI-RS transmissions. In one respect, the RE assignment in RB 480 differs from the assignment in RB 450 in that the pairs of RE 482 and 484 are assigned to the CSI-RS in RB 480 and were left unassigned (that is, they are available for data transmissions) in the RB 450 illustrated in FIG. 4B. The problem that occurs when these RE 482, 484 are used for CSI-RS and how this problem can be solved using STBC will be explained later in detail.
In some designs, when 2 REs are available for 4 CRS, using SFBC using 2 beams that the UE 120 is aware of can be advantageous to use the maximum power for SFBC-FSTD. In some designs, when less than 4 REs are available for 4 CRS, or 1 RE for 2 CRS, a modulation symbol can be transmitted through beams that the UE 120 can estimate using CRS. In some designs, the additional REs 482, 484 can simply be omitted. It should be noted that, in some designs, REs that break the SFBC array may be allowed. The decision to use REs for CSI-RSs or to protect the SFBC can be determined at the network level during the configuration of a network (eg, by eNB 110).
In some designs, to determine the channel quality of other cells, a UE 120 may have information regarding where to look for the CSI-RSs of a neighboring cell, where this information from the UE 120 is minimal. To enable this, CSI-RS antenna patterns can be derived based on one or more of a subframe index, a radio frame index, a single frequency network number (SFN), and a cell ID. Based on the information, the UE 120 can assign CSI-RS transmissions from a neighboring eNB 110.
In some designs, as described above, changing the CSI-RS antenna patterns on the RBs may, in one aspect, allow full power utilization when transmitting the CSI-RS signal from an antenna.
In some designs, the various CSI-RS antenna ports can be arranged orthogonal to each other so that groups of a given port size (e.g. 8, 4, 2, or 1) can be orthogonal to each other (e.g. example, due to time-frequency separation). Furthermore, a group with a smaller number of antennas can form a subgroup of the group with a larger number of antennas. For example, the CSI-RS resource allocation pattern for groups of 8 antenna ports may comprise two CSI-RS patterns for groups of 4 antennas (4Tx) which, in turn, may comprise 2 CSI-RS allocations for CSI-RS of 2 transmission ports 2. Therefore, in some designs, REs are assigned for CS-RS transmission, based on the number of transmitting antennas used for transmission of the reference signal (for example, 8, 4, or 2), where the function is nested with respect to the number of transmitting antennas, such that a first resource pattern corresponding to a first number (for example, 8 or 4) of transmit antennas is a superset of a second resource pattern corresponding to a second number of transmit antennas (eg 4 or 2) when the first number is greater than the second number.
In some designs, CSI-RS REs may be selected to be in RE locations so that the number of affected SFBC RE pairs can be minimized (it should be noted that it may be a set of 2 REs even for SFBC-FSTD). In some designs, minimization can result in a single RE not grouped into a symbol in which the CSI-RS REs are assigned. In some designs, minimization may result in no non-clustered REs (that is, all data REs are assigned to CSI-RS transmissions).
In some designs, the encoding procedure used for data transmission may change from SFBC / SFBC-FSTD to STBc, when the number of REs available has the form 2n + 1 for SFBC and 4n + 2 for SFBC-FSTD in symbols OFDM neighbors. This change to the data encoding procedure can, in one aspect, help minimize the number of orphaned REs. In various designs, the available REs can be calculated for each RB or for the entire data allocation.
As described in detail below, REs can be assigned to CSI-RS transmissions to cover different contiguous (or non-contiguous) portions of the channel bandwidth in different subframes, thus covering the entire bandwidth when viewed collectively. across all subframes. The bandwidth and CSI-RS RE assignment patterns can be chosen so that the eNB 110 can avoid selectively dropping the signal, such as a physical broadcast channel (PBCH), a secondary sync signal (SSS), and Mandatory signal transmissions, such as radiolocation and System Information Blocks (SIB). In some designs, mandatory transmissions of such signals, such as radiolocation and SIB, directed to UEs
ES 2 586 666 T3 legacy 120 can be carried out on RBs that do not contain CSI-RS and appear as expected by legacy UE 120, while these signals can be transmitted and carried to UE compatible with CSI-RS120 on other RBs selected by eNB 110.
In some designs, the CSI-RS antenna port space can be divided between eNB 110 of different power class (more generally, two eNB, of which one is a dominant interference source with respect to the other, get a partition different). For example, in some designs, macrocell eNB 110s get one set of REs from CSI-RS, picocells get another set, and femtocells can get multiple sets of REs from CSI-RS. In general, the dominant interference source can be configured to silence the CSI-RS space of the weaker eNB. Assignment based on power class can be static, semi-static (for example, use an upper layer message), or dynamic. Cooperative cells, in which one cell can silence the CSI-RS of the other cell and can select the CSI-RS pattern to use so that the silencing and CSI-RS transmissions occur on the same OFDM symbols, allow increase the power of CSI-RS.
In some designs, code division multiplexing (CDM) can be used on CSI-RS symbols (ie symbols where REs are assigned to CSI-RS transmission). In one aspect, the use of CDM can address the problem described above about power utilization. For example, instead of sending antenna ports 1, 5 on different REs in two neighboring OFDM symbols, they can be code division multiplexed (CDM) across the two REs using two orthogonal sequences. In some designs, CDM can be used for a higher range DM-RS pattern (for example, range 8) and FDM can be used for lower ranges (for example, ranges 4 and 2).
Referring now to FIGS. 6 to 13, some examples of RE assignments to CSI-RS signals are illustrated, using TLE version 10. In FIGS. 6 to 13, REs designated by letter C may represent REs assigned to CRS, and REs designated by letter U may represent REs assigned to UE-RS.
FIG. 6 is a block diagram representation of an RB 600 showing the pattern assignment from RE to CSI-RS for the case of 2 CSI-RS ports in normal cyclic prefix (CP) subframes, for both frame structures (FS) FS 1 and FS 2.
FIG. 7 is a block diagram representation of an RB 700 showing the pattern assignment from RE to CSI-RS for the case of 4 CSI-RS ports in normal cyclic prefix (CP) subframes, for both frame structures (FS) FS 1 and FS 2.
FIG. 8 is a block diagram representation of an RB 800 showing the pattern assignment from RE to CSI-RS for the case of 8 CSI-RS ports in normal cyclic prefix (CP) subframes, for both frame structures (FS) FS 1 and FS 2.
FIG. 9 is a block diagram representation of an RB 900 showing an alternative pattern assignment from RE to CSI-RS for the case of 4 CSI-RS ports in normal cyclic prefix (CP) subframes, for the structure of frame FS 2.
FIG. 10 is a block diagram representation of an RB 1000 showing a pattern mapping from RE to CSI-RS for the case of 2 CSI-RS ports in extended cyclic prefix (CP) subframes, for both frame structures (FS) FS 1 and FS 2.
FIG. 11 is a block diagram representation of an RB 1100 showing the mapping of patterns from RE to CSI-RS for the case of 4 CSI-RS ports in extended cyclic prefix (CP) subframes, for both frame structures (FS) FS 1 and FS 2.
FIG. 12 is a block diagram representation of an RB 1200 showing the pattern mapping from RE to CSI-RS for the case of 8 CSI-RS ports in extended cyclic prefix (CP) subframes, for both frame structures (FS) FS 1 and FS 2.
FIG. 13 is a block diagram representation of an RB 1300 showing an alternative pattern assignment from RE to CSI-RS for the case of 8 CSI-RS ports in extended cyclic prefix (CP) subframes, for the structure of frame FS 2.
In general, when certain data REs are assigned (or discarded) for CSI-RS transmission, such information may or may not be known by different UE 120. For example, legacy UE 120 (eg UE 120 version 8) cannot detect CSI-RSs, whereas version 10 UEs can detect CSIRS. In such cases, data transmissions to new UEs and legacy UEs 120 may be adjusted in rate or selectively dropped for compatibility reasons.
In some designs, selective removal can be achieved simply by discarding in the transmissions
ES 2 586 666 T3 data that would have been transmitted in the REs now assigned to the CSI-RS. A legacy receiver can receive and retrieve transmissions using, for example, error coding techniques. In some designs, the rate adjustment can be achieved by discarding the REs assigned to the CSI-RSs, but transmitting all the data bits intended for transmission to the new UE 120. The data can also be selectively removed for UEs not detected by the CSIs. -RS. In UEs that detect CSI-RS, rate adjustment or selective kill can be used, but both the UE and the eNB need to know the approach used. Hopefully, speed tuning will perform better than selective delete. In some designs, the available data REs can be used in data transmissions by ordering first in frequency and then in time.
Referring to FIG. 14, two possible resource allocation schemes are shown for allocating data REs to CSI-RS transmissions in a group of four contiguous one-symbol REs. It should be understood that similar schemes can also be used for other ER group sizes. In group 1400, a pair of neighboring REs 1404 may be assigned to CSI-RSs, thus leaving the RE pair 1402 available for data transmission. In another scheme, in group 1401, a first RE of the pair of RE 1403 assigned to CSI-RS can come from a neighboring pair of RE, and a second RE of the pair of RE 1403 can come from a second neighboring pair by RE. As can be seen, the illustrated scheme for group 1401 results in the selective removal of two pairs of RE data from CSI-RS transmissions. In contrast, only one data RE pair is selectively removed in group 1400, thus allowing data transmission in RE pair 1402 using a group coding scheme (eg, SFBC).
However, for transmission diversity schemes such as SFBC and SFBC-FSTD, when the number of data REs available within an RB to which CSI-RS transmissions have been allocated is not a multiple of 2 or 4, the The use of the remaining Data Re may have to be carefully planned to reduce or avoid the waste of Data RE, as the remaining RE may not be assigned to SFBC or SFBC-FSTD groups. For example, SFBC and SFBC-FSTD require the assignment of REs in groups of 2 and 4 REs, respectively. Table 1 below lists possible CSI-RS and CRS port combinations that result in these cases.
Referring to Table 1, the first column indicates the number of CRS ports assumed for a particular CSI-RS allocation scenario. The second column Transmission Diversity Scheme indicates the transmission coding technique used for data transmissions. The third column lists several possible CSI-RS antenna port assignments. The fourth column indicates whether the combination of the reference signal configurations from the first three columns can be used in certain designs. The fifth column shows any possible speed adjustment problems in each RB that may arise for the data and reference signal configurations shown in the first three columns.
Table 1
<td>Ports CRS</td><td>Diversity Scheme Transmission</td><td>CSIRS ports</td><td>Supported preference</td><td>Speed setting issues in CSIRS symbols</td>
<td> 1</td><td>Rank 1 Transmission</td><td> 2,4,8</td><td>Not supported due to the effect of fewer CRS numbers on control performance</td><td>No problems occur</td>
<td rowspan="3"> 2</td><td rowspan="3">SFBC</td><td> 2</td><td>Supported</td><td>11 RE of available data 5 pairs of SFBC + 1 RE of orphan data.</td>
<td> 4</td><td>Supported</td><td>10 RE available data</td>
<td> 8</td><td>Supported</td><td>8 RE available data</td>
<td> 4</td><td>SFBC-FSTD</td><td> 2</td><td>Not supported Unclear need for CSIRS # <CRS #.</td><td>11 RE of available data. 2 pairs of SFBC-FSTD, 3 RE of orphan data.</td>
<td rowspan="2"></td><td rowspan="2"></td><td> 4</td><td>Supported</td><td>10 RE of available data. 2 pairs of SFBC-FSTD + 2 orphaned REs.</td>
<td> 8</td><td>Supported</td><td>8 RE of available data.</td>
Referring to FIG. 15, for symbols 1500, 1502, 1504, 1506, 1512, 1513, 1514 and 1515 containing CSI-RS, there are 11 REs available. These symbols may correspond, for example, to symbol indices 5, 6, 9, 10, 12 or 13, as shown in FIGS. 3-13. The CSI-RS assignment patterns illustrated in FIG. fifteen they highlight, among other aspects, the idea of speed adjustment as regards CSI-RS, where the antenna port changes in the CSI-RS symbols and in the RBs. In some designs, the first 10 REs available (counting from the top) can be used in 5 pairs of SFBC, marked with a combination of lowercase and uppercase letters A to E and G to K. For the remaining REs 1502 (designated as F and f) in the neighboring symbols (the so-called orphan REs), only one modulation symbol and can be transmitted from a single CRS antenna port. As illustrated, there are 2 symbols 1500, 1504 containing CSI-RS that have the orphan RE. The port of
ES 2 586 666 T3 CRS antenna used in an RB in the two OFDM symbols that contain the CSI-RS can be different. The antenna port used for the orphan REs in the OFDM symbol containing the CSI-RSs may change in the RBs (designated as AP 0 and AP 1 in FIG. 15). In one aspect, this can ensure that both CRS antenna ports are used in nearly the same way when multiple RBs are used for SFBC transmission.
In some designs the following antenna port may be used in the RE mapping scheme. For early CSI-RS 1500 symbols, antenna port 0 is used on even RBs (represented by symbol 1500) and antenna port 1 is used on odd RBs (symbol 1502). For second CSI-RS 1500 symbols, antenna port 0 is used on odd RBs (symbol 1506) and antenna port 1 is used on even RBs (symbol 1504). For clarity, only two symbols containing REs of RS-CSI in the RB are shown in FIG. fifteen.
As illustrated in FIG. 15, for each symbol that includes CSI-RS assignments there are 11 REs available for data transmissions. The first 10 REs (from the top) can be used in 5 SFBC pairs for data transmissions. The remaining RE (orphan RE) can satisfy the following conditions: (1) in the orphan RE only one modulation symbol can be transmitted and from a single CRS antenna port; (2) there are 2 symbols containing CSI-RS that have the orphan RE; the CRS antenna port used in an RB in the two OFDM symbols containing CSI-RS is different; and (3) the antenna port used for the orphan REs in the symbol containing CSI-RS changes in the RBs (even and odd). In one aspect, the change ensures that both CRS antenna ports are used in nearly the same way when multiple RBs are used for SFBC transmission.
It should be appreciated that the mapping scheme for symbols 1500, 1504, 1512, and 1514 achieves the conditions described above. For 1502, antenna port 0 is used on even RBs and antenna port 1 is used on odd RBs. For second CSI-RS 1504 symbols, antenna port 0 is used on odd RBs and antenna port 1 is used on even RBs. It should be noted that although the last RE in the mapping scheme for symbols 1500, 1504, 1512 and 1514 has been selected as the orphan RE, it should be understood that any one of the 11 available REs may be selected as the orphan RE based on performance. In addition, the particular antenna ports and the odd / even RBs of the mapping scheme for symbols 1500, 1504, 1512, and 1514 may vary as long as the speed setting relative to CSI-RS is done with one port. of antenna that changes in the symbols of CSI-RS and in the RBs.
Referring below to symbols 1501, 1503, 1513 and 1515, the correlation schemes are illustrated for speed adjustment as it relates to CSI-RS, where the antenna port changes in CSIRS symbols and in RBs. . The correlation scheme may include rate adjustment as regards data transmissions using the SFBC-FSTD transmit diversity scheme. In symbols that do not contain CSI-RS (not illustrated in FIG. 15), the version 8 mapping scheme can be used. In symbols containing CSI-RS, for example symbols 1501, 1503, 1513 and 1515, there are 10 REs available. The first 8 REs available can be used to allow 2 pairs of SFBC-FSTDs. For the remaining 2 REs (orphan REs), the following correlation conditions can be met: (1) of the two orphan REs, one uses an SFBC transmission scheme using two antenna ports; (2) The CRS antenna ports used for the orphan REs within an RB in the two OFDM symbols containing CSI-RS are different. That is, if one uses antenna ports (0, 2) for orphan REs in the first CSI-RS symbol, then one uses antenna ports (1, 3) for orphaned REs in the second CSI-RS symbol; (3) the antenna ports used for the orphan REs change between the RBs. This ensures that the 4 CRS antenna ports are used almost equally when multiple RBs are used for SFBC transmission. Example mappings compatible with the above conditions are illustrated for symbols 1501, 1503, 1513, and 1515.
In some designs, data REs that occupy the same time-frequency locations as CSIRS REs from neighboring cells may be silenced (ie, not used) during data transmissions in a given cell. In one aspect, silencing such data REs can improve the efficiency of CSI-RS channel estimation from neighboring cells, for example for CoMP and HetNet scenarios. In some designs, from the perspective of UE 120s, muting may simply mean that the eNB 110 adjusts the speed of data transmission relative to the silenced REs, and the REs cannot be muted (i.e. not used in no transmission) over the eNB 110.
However, the receiver of a UE 120 that is unaware of the squelch and therefore tries to receive data on the squelched REs, may perform less well. Therefore, in one aspect, information provided to UEs 120 related to squelch locations may be useful for UE 120 to maintain receiver performance. In some designs, UE 120s can adjust their speed in regards to silenced REs.
FIG. 16 is a block diagram representation of a group of two symbols 1600 of an RB in which a CSI-RS is transmitted. REs include pairs of SFBC 1602, 1608, and 1612 assigned for data transmissions. The RE 1604s are assigned to the CSI-RS transmissions in the carrier cell. RE 1606s are assigned to CSI-RS transmissions in a neighboring cell and are silenced in the carrier cell. Likewise, the RE 1610s are also silenced in the carrier cell. It can be seen that although
In ES 2 586 666 T3 the pairs of SFBC 1602 and 1608 comprise contiguous REs in time-frequency, the group of SFBC 1612 is divided into two parts due to the intermediate CSI-RS pattern 1604 and the silenced REs 1606. Using the velocity adjustment technique described above to adjust the velocity in regards to muted tones and CSI-RS tones can lead to situations where the use of SFBC on tones that are separated by more than Two tones can degrade the performance of the SFBC scheme.
In some designs, as illustrated by symbols 1601 of FIG. 16, tones for which a paired RE cannot be found can be treated as 1603 orphan REs. It should be noted that such orphan REs can also be generated on 2 CRS ports, even if the number of available data REs is even (as shown in group 1601). The scheme described above can therefore be applied to these orphan ERs. That is, if there are one or more orphan REs that cannot be paired for the SFBC, only one modulation symbol is transmitted on each orphan RE using only one antenna port. In some designs, orphaned REs may also be unused (that is, no transmissions are made). The antenna port used changes across the RBs. An additional optimization can also be considered in which the antenna ports change for different orphan REs on the same OFDM symbol within an RB. However, the complexity of correlation increases and depends on the exact combination of silenced CRS, CSI-RS and RE. Also, for 4 CRS when the number of allowed SFBC pairs is not a multiple of 2, the antenna ports used for the unpaired SFBC may change across the RBs.
Referring to FIG. 17, an example of a 1700 correlation scheme for rate adjustment is illustrated as regards CSI-RS REs and silenced REs using a space-time block coding (STBC) transmission diversity scheme . It should be noted that for simplicity and clarity, the 1700 mapping scheme is only shown on the two symbols that contain CSI-RS. The 1700 mapping scheme is the same for odd and even RBs. The 1700 mapping scheme uses STBC for 2 CRS antenna ports on CSI-RS / silenced RE containing symbols. It should be noted that the SFBC can still be used in other symbols.
With reference to FIG. 18 and FIG. 19, in designs that use squelch, an alternative scheme that uses STBC and STBC-FSTD can be used for 2 and 4 CRS antenna ports respectively on symbols containing CSI-RS or muted tones. In the alternative scheme, SFBC and SFBC-FSTD can be used in other symbols that do not have any silenced RE or CSI-RS assignments. In SFBC-FSTD, the antenna ports can toggle between (0, 2) and (1, 3) in the available REs. In some designs, for 4 CRS antenna ports, the antenna ports used for STBC can be set to (0, 2) in the first available REs of even RBs and to (1, 3) in the first available REs of odd RBs. In one aspect, the fixed mapping can help ensure the same utilization of all antenna ports.
For example, in FIG. 18, a symbol pair 1800 (eg RB symbols 5 and 6 where CSI-RSs are assigned) is shown for an even RB. After the REs of a symbol are assigned to SFBC-FSTD pairs, CSI-RS and silenced, as described above, the remaining RE (denoted D1) in each symbol forms an RE 1802 pair that can be assigned to antenna ports (0, 2). Also, the RE 1902 pair in the 1900 symbol pair can be assigned to antenna ports (1, 3).
In some designs, as described above, data transmissions can be adjusted in rate for CSI-RS and muted tones to transmit diversity schemes such as SFBC and SFBC-FSTD. In some designs where CSI-RS transmissions are performed without squelch, assigning REs to CSI-RSs can result in orphan REs in two cases: (a) 2 CSI-RS and 2 CRS and ( b) 4 CSI-RS and 4 CRS, as described above. In some designs, single antenna port transmissions can be used on orphan REs for the case of 2 CRS. In some designs, SFBC transmissions can be used on orphan REs for the 4 CRS case. Antenna ports can switch through RBs (odd and even) and through OFDM symbols to ensure mitigation of power imbalances and also uniform allocation of transmission resources for all antenna ports.
Referring again to FIG. 16, as described above, correlation schemes are shown for two pairs of symbols 1600 and 1601. From FIG. 16 it can be seen that the REs assigned to the SFBC B 1612 pair are separated by three subcarriers. In some designs, a UE 120 may process the received signal corresponding to signals transmitted in these REs assuming the same channel characteristics for all REs in a given group of REs (eg, both REs in a pair of REs). This assumption can be made by certain conventional UE 120, such as version 8 UE 120, since typical REs assigned to a resource pair in version 8 are neighboring REs or are separated by an RE in a symbol, and by others. UE 120 to simplify implementation. Therefore, in certain designs, a pair of separate REs can result in lower performance for UE 120s that assume the same channel characteristics for both REs of a pair of REs. The term "pair of separate ERs" refers to pairs of ERs in which the constituent ERs are separated by more than one ER. For example, the two RE B's in FIG. 16 have a separation of 3 REs and are therefore considered a pair of separate REs.
Certain designs can overcome potential performance issues due to receiving RE
ES 2 586 666 T3 separated, in one aspect, using RE pair assignment techniques in which the available REs of a symbol are assigned to minimize the spacing between the REs of a Re pair. For example, in some designs, RE assignment can be accomplished by scrolling through the RE available in a given symbol, for example from top to bottom of the 1600 or 1601 graphical representation, and assigning RE to RE pairs using a technique, for example the one described by the pseudocode presented in Table 2. It should be noted that the pseudocode presented in Table 2 is for the assignment of RE in a given RB of 12 RE. As indicated in detail below, a similar allocation may be carried out for portions of resource allocations that include multiple RBs (ie, multiple groups of 12 REs allocated to a single UE).
Table 2
N-1;
While (N <12) {
if N and N + 1 are data REs, then {make N and N + 1 a pair of SFBC;
N = N + 2;
} if not, if (N <= 10 and N and N + 2 are RE data) then {make N and N + 2 a pair of SFBC;
N = N + 3;
} if not, N = N + 1; // this corresponds to N REs of unused data / N REs that are not REs of data.
}
As can be seen in Table 2, the assignment of REs according to the code shown will result in pairs of REs in which the constituent REs are not separated by more than a single carrier in a symbol.
Referring now to FIG. 20, an example RE 2000 assignment is illustrated, when multiple consecutive RBs are used for transmissions to a given UE 120. Those skilled in the art will appreciate that the pseudo-code in Table 2 can be modified if run against an appropriate upper threshold of N (eg, N <24, when using two RBs for a given UE 120). Furthermore, as can be seen in FIG. 20, the use of consecutive RBs can result in a reduced number of non-clustered (or orphaned) REs. For example, while the REs denoted E and e in the symbol pair 1601 are not grouped, the corresponding REs of FIG. 20 are matched and allocated in the ER 2000 allocation, thus reducing the number of non-clustered ERs.
A similar RE assignment technique can be used for 4 CRS ports using SFBC-FSTD. In this case, if the number of SFBC pairs available in an RB is odd, then the last SFBC pair can also be omitted. Alternatively, if the number of SFBC pairs found in an OFDM symbol is odd, the last SFBC pair can be omitted. This will ensure that the number of SFBC pairs is even, which in turn ensures that all 4 CRS ports are used equally.
Alternatively, in some designs, RE pairs cannot be formed in the RBs (for example, REs such as the E and e of symbol pair 1601 can be left ungrouped even when it is possible to pair them with close REs from another block resources).
In some designs, where frequency domain duplex (FDD) transmission is used, CSI-RSs cannot be assigned in subframes that include PBCH and sync signals. In some designs, the paging subframes may be excluded from the CSI-RS RE assignment. For example, this may result in no CSI-RS signal being sent at subframe indices 0, 4, 5, and 9 in a transmit frame structure.
In designs where CSI-RSs are omitted in such subframes, REs can still be assigned so that relay access and backhaul division can be performed taking into account the omission of CSI-RS signals in, for example, subframes 0, 4, 5, and 9.
When using time domain duplexing (TDD) on a wireless channel, in some designs, the PBCH may be at subframe index 0. In the first 4 symbols of transmit slot 1, two symbols may include a transmission of reference signals and the other two not. In some designs, the primary sync signal (PSS) may be transmitted in the third OFDM symbol in subframes 1 and 6. Also, the secondary sync signal (SSS) may be transmitted at the last OFDM symbol in subframes 0 and 5. In some designs, these symbols may be excluded from CSI-RS transmissions. As a result of the exclusion of REs described above, 30 CSI-RE REs may be available in subframes with PBCH and SSS, and 54 CSI-RS REs may be available in subframe 5 with SSS only. In some designs, alternate subframe 5 contains SIB1, and CSI-RS assignment may also avoid such subframes.
ES 2 586 666 T3
Table 3 shows different uplink-downlink configuration modes (column 1) and the periodicity of switch points for each mode (column 2) with the assignment of each subframe of the given configuration to uplink transmissions (U) , downlink transmissions (D) and sync signals (S).
Table 3
<td rowspan="2">Uplink configurationdownlink</td><td rowspan="2">Frequency of downlink to uplink switch points</td><td colspan="10">Subframe number</td>
<td> 0</td><td> 1</td><td> 2</td><td> 3</td><td> 4</td><td> 5</td><td> 6</td><td> 7</td><td> 8</td><td> 9</td>
<td> 0</td><td>5 ms</td><td>D</td><td>S</td><td>OR</td><td>OR</td><td>OR</td><td>D</td><td>S</td><td>OR</td><td>OR</td><td>OR</td>
<td> 1</td><td>5 ms</td><td>D</td><td>S</td><td>OR</td><td>OR</td><td>D</td><td>D</td><td>S</td><td>OR</td><td>OR</td><td>D</td>
<td> 2</td><td>5 ms</td><td>D</td><td>S</td><td>OR</td><td>D</td><td>D</td><td>D</td><td>S</td><td>OR</td><td>D</td><td>D</td>
<td> 3</td><td>10 ms</td><td>D</td><td>S</td><td>OR</td><td>OR</td><td>OR</td><td>D</td><td>D</td><td>D</td><td>D</td><td>D</td>
<td> 4</td><td>10 ms</td><td>D</td><td>S</td><td>OR</td><td>OR</td><td>D</td><td>D</td><td>D</td><td>D</td><td>D</td><td>D</td>
<td> 5</td><td>10 ms</td><td>D</td><td>S</td><td>OR</td><td>D</td><td>D</td><td>D</td><td>D</td><td>D</td><td>D</td><td>D</td>
<td> 6</td><td>5 ms</td><td>D</td><td>S</td><td>OR</td><td>OR</td><td>OR</td><td>D</td><td>S</td><td>OR</td><td>OR</td><td>D</td>
In some designs, the eNB 110 can perform a paging operation based on the following paging settings: In FDD, select the paging to be in the subframes: {9} or {4, 9} or {0, 4, 5, 9}, and repeat it periodically. In TDD, paging on subframes {0}, {0, 5}, {0, 1, 5, 6}, periodically. In setting 0, only 3 DL OFDM symbols in the special subframes may be available and therefore CSI-RS may not be performed on these symbols.
Therefore, in some designs, the bandwidth covered by the CSI-RS transmission can be divided into multiple groups (for example, two groups). For example, in subframe 0, 50% of the bandwidth can be occupied by CSI-RS transmission, and in subframe 5, 50% of the remaining bandwidth can be occupied by CSI-RS transmissions. In some designs, the data transmissions to the UEs 120, which detect the CSI-RS transmissions, can be made outside of these subframes. In some designs, CSI-RS may not be allowed in setting 0.
In wireless systems comprising multiple cells, CSI-RS transmissions may be assigned REs in multiple subframes. In one aspect, CSI-RS RE allocation across multiple subframes can provide better reuse of the same resources in neighboring cells. In one aspect, the use of multiple subframes may allow for subframing in HetNet configurations.
Assigning CSI-RS across multiple subframes can also help with the use of CSI-RS in relay operations. For example, a relay node may transmit CSI-RS in DL access subframes and may need to detect CSI-RS of macro cells on a DL backhaul link. By using multiple subframes, a relay node may not have to transmit and receive CSI-RSs in the same subframe, thus reducing the complexity of the relay design.
In various designs, the division of the subframes does not necessarily have to divide the subframes with the periodicity of one frame (eg, 10 ms). For greater flexibility, RE patterns can be defined for CSI-RSs, and information can be transported from eNB 110 to UE 120 using bitmaps. The use of bitmaps also allows for future compatibility with other RE mappings. For example, in some designs, unevenly spaced (or aperiodic) subframes may be assigned to reference signal transmissions, where the subframe pattern repeats over a subframe period. As a non-limiting example, subframes 0, 5, and 20 can be allocated in a given sequence of subframes for a period of 40 milliseconds, where the pattern repeats every 40 milliseconds. Correspondingly, the aperiodic subframe pattern can be transmitted to the UEs 120 using a downlink message, and the UEs 120 can be configured to receive the aperiodic (or unevenly spaced) transmission pattern, which has a repeat period.
In some designs, REs assigned to CSI-RS transmissions, for example to a particular antenna port, can be skipped for a period of time. In one aspect, hopping may allow UE 120s to receive at least some CSI-RSs without being affected by a transmission from a neighboring cell that generates significant interference. In some designs, a different hop pattern can be used for each antenna port. Alternatively, in some designs, hopping can be defined for a group of antenna ports (that is, the transmissions for all antenna ports in the group collide or do not collide). The second alternative may work better if a UE 120 can determine when the CSI-REs collide and does not use the CQI in that case. In the first alternative, the chances of some antenna ports colliding may be higher, causing the reported CQI / PMI to be erroneous more often.
ES 2 586 666 T3
In some designs, the squelch pattern can be selected based on the power class of the carrier network. For example, in some designs, an eNB 110 for a macro cell can silence the CSI-RS assignments of all pico cells. In some designs, an eNB 110 for a femto cell can silence the CSI-RS allocation of all macro cells and pico cells. In some designs, the squelch pattern can be modified based on response information from the UE 120.
FIG. 21 is a flowchart representation of a wireless communication process 2100. In box 2102 a plurality of data resource elements (RE) available in a subframe are identified. The available data REs may comprise, for example, REs that are assigned to CSI-RS transmission or REs that are silenced for corresponding CSI-RS transmissions in other cells. Available ERs can include, for example, ERs assigned to SFBC pairs or SFBC-FSTD pairs, as illustrated in FIG. fifteen. In box 2104, the REs of the plurality of available data REs are assigned for data transmission to a wireless device in groups of a predetermined number of REs, such that all assigned data REs within a group are within of a predetermined number of respective symbols in the time domain, and within a second predetermined number of respective subcarriers in the frequency domain, thus resulting in one or more non-clustered REs. For example, as illustrated in FIGS. 15-20, REs not assigned to CSI-RSs and / or not silenced can be grouped into groups of REs on the same symbol or groups of REs on neighboring symbols. In some designs, REs separated by two symbols can also be grouped (eg symbols 5, 6, 9 and 10 in an RB where CSI-RSs are assigned). In some designs, REs that are separated by one or two subcarrier indices may be grouped into a single data transmission group (eg, the RE pair 1516 of FIG. 15).
In some designs, some REs may be discarded after the remaining REs are assigned to CSI-RS and data transmissions (eg, the RE denoted F in symbol 1500). In some designs, the remaining REs can be assigned to another transmission to other wireless devices (eg, a data transmission to another UE 120). In some designs, the remaining REs can be left unused (that is, no transmissions are made).
In some designs, the grouping of REs may be limited to REs that are within the same resource block. For example, the same RE assignment pattern (eg, as described in FIGS. 15 to 17) can be repeated in every RB where reference signal transmissions are assigned. It should further be appreciated that the various RE assignment patterns described above may depend on the number of transmit antenna ports used for another reference signal (eg, CRS).
In some designs, the data transmission assignments to REs within the group of REs may comprise space-frequency block code (SFBC) and space-time block code pairs. In some designs, the data transmissions within the RE group may comprise a transmission diversity scheme. The transmission diversity scheme can be, for example, an Alamouti scheme.
In some designs, the at least one non-clustered RE can be used for transmission to the same device to which the data transmissions are sent. However, the transmission scheme used may be different. For example, although SFBC pairing can be used for REs in the transmission group, another transmission scheme (eg, single antenna port transmission) can be used for non-grouped REs.
FIG. 22 is a block diagram representation of a part 2200 of a wireless communication apparatus. Module 2202 is for identifying a plurality of data resource elements (RE) available in a subframe. Module 2204 is for assigning the REs of the plurality of data REs available for data transmission to a wireless device in groups of a predetermined number of REs, such that all data REs assigned within a group are within a predetermined number of respective symbols in the time domain, and within a second predetermined number of respective subcarriers in the frequency domain, thus resulting in at least one non-clustered RE. In some designs, an identifier may be used for the allocation of the available data resource REs and an allocator may be used to allocate REs from the plurality of remaining data REs.
FIG. 23 is a flowchart representation of a wireless communication process 2300. In box 2302, the resource elements (RE) of a symbol are assigned to a transmission of reference signals. In box 2304, at least some of the remaining REs in the symbol are muted, thereby preventing data transmission in the muted REs. In box 2306, the reference signal is transmitted by increasing the transmitted power of the reference signal. As described above, in some designs, silenced REs may comprise transmission resources (eg, RE locations) used for transmission of the reference signal in another neighboring cell (eg, CSI-RS).
FIG. 24 is a block diagram representation of a part 2400 of a wireless communication apparatus. Module 2402 is for assigning resource elements (RE) of a symbol to a transmission of reference signals. Module 2404 is to silence at least some of the remaining REs of the symbol, thereby preventing data transmission on the silenced REs. Module 2406 is for transmitting the signal
Reference ES 2 586 666 T3 by increasing the transmitted power of the reference signal. In some designs, REs can be assigned by an allocator, squelch can be carried out by a processor, and a transmitter can be used to transmit the reference signal.
FIG. 25 is a representation in flowchart form of a wireless communication process 2500. In box 2502, an aperiodic transmission resource pattern is assigned to a reference signal that has multiple subframe periodicity. In box 2504, the reference signal is transmitted according to the aperiodic transmission resource pattern. In some designs, the aperiodic transmission resource can be signaled to UEs 120 using a downlink message. In some designs, the downlink message may comprise a bitmap indicating the REs used for transmission of the reference signal. As described above, aperiodic transmissions can be assigned so that a relay node does not have to receive and transmit the reference signal in the same transmission subframe. In some designs, the aperiodic transmission resource pattern may include unevenly (or aperiodic) spaced subframes, for example subframes 0, 5, 20, by a given number of subframes (for example, for 40 milliseconds) and the pattern of unevenly or aperiodic spaced subframes can be repeated.
FIG. 26 is a block diagram representation of a part 2600 of a wireless communication apparatus. Module 2602 is for assigning an aperiodic transmission resource pattern to a reference signal having multiple subframe periodicity. Module 2604 is for transmitting the reference signal according to the aperiodic transmission resource pattern.
FIG. 27 is a flowchart representation of a wireless communication process 2700. In box 2702, resources are allocated to a transmitter of the reference signal depending on the power class of the transmitter. In box 2704, which uses the allocated resources, transmission of the reference signal from the transmitter is carried out. As described above, the power class can be macro, peak or femto type. In one aspect, the allocation of transmission resources based on power class can help avoid interference from macro cells with pico cells or femto cells, and from base femtos to other femto / pico / macro base stations.
FIG. 28 is a block diagram representation of a part 2800 of a wireless communication apparatus. Module 2802 is for allocating resources to a reference signal transmitter depending on the power class of the transmitter. The module 2804 is to carry out, using the allocated resources, the transmission of the reference signal from the transmitter. In some designs an allocator may be provided to allocate resources to a transmitter.
FIG. 29 is a flowchart representation of a wireless communication process 2900. In box 2902, from a set of all available transmission resources for a reference signal, a subframe dependent transmission resource pattern is assigned to the reference signal in a given subframe. In box 2904, the subframe dependent assigned pattern varies over a plurality of subframes, such that all available transmission resources in the set are used at least once. The subframe dependent pattern in the given subframe does not overlap with the transmission resources allocated to a first signal and a second signal. In at least one subframe of the plurality of subframes, at least one transmission resource in the set is assigned to the first signal rather than the reference signal. In some designs, the first signal can be a PBCH or an SSS, and the second signal can be a paging signal or a SIB.
FIG. 30 is a block diagram representation of a part 3000 of a wireless communication apparatus. Module 3002 is for allocating, from a set of all available transmission resources for a reference signal, a subframe dependent transmission resource pattern to the reference signal in a given subframe. Module 3004 is for modifying the subframe dependent assigned pattern in a plurality of subframes, such that all available transmission resources in the set are used at least once. The subframe dependent pattern in the given subframe does not overlap with the transmission resources allocated to a first signal and a second signal. Furthermore, in at least one subframe of the plurality of subframes, at least one transmission resource in the set is assigned to the first signal rather than the reference signal.
FIG. 31 is a flow chart representation of a wireless communication process 3100. In box 3102 a plurality of data resource elements (RE) available in a subframe are identified. In box 3104, the plurality of available data REs are assigned to transmit data in at least one space-frequency block coding group (SFBC) and at least one space-time block coding group ( STBC), thus resulting in no non-clustered RE.
FIG. 32 is a representation in block diagram form of a part 3200 of a wireless communication apparatus. Module 3202 is for identifying a plurality of data resource elements (RE) available in a subframe. Module 3204 is for assigning the plurality of available data REs to the
ES 2 586 666 T3 data transmission in at least one space-frequency block coding group (SFBC) and in at least one space-time block coding group (STBC), thus resulting in no RE not used.
FIG. 33 is a flow chart representation of a wireless communication process 3300. In box 3302 a reference signal is received in a subframe of REs assigned to transmissions of the reference signal. The subframe comprises a plurality of remaining data REs. At box 3304, data is received from at least one of the plurality of remaining data REs. The data is transmitted in groups of a predetermined number of REs, such that all data REs allocated within a group are within a predetermined number of symbols in time and a second predetermined number of respective frequency REs, giving as well as resulting at least one non-clustered RE in the subframe (eg, as illustrated in FIG. 15).
In some designs, the reference signal is the CSI-RS. In some designs, the data received from the plurality of remaining data REs may be modulated as space-frequency block code (SFBC) and space-time block code pairs. In some designs, data transmissions within the RE group can be carried out using a transmission diversity scheme, such as an Alamouti scheme.
FIG. 34 is a block diagram representation of a part 3400 of a wireless communication apparatus. Module 3402 is for receiving a reference signal in a subframe of REs assigned to transmissions of the reference signal, where the subframe comprises a plurality of remaining data REs. Module 3404 is for receiving data from at least one of the plurality of remaining data REs, where the data is transmitted in groups of a predetermined number of Re, such that all assigned data REs within a group are within a predetermined number of symbols in time and a second predetermined number of respective frequency REs, thus resulting in at least one non-clustered RE in the subframe.
FIG. 35 is a flowchart representation of a wireless communication process 3500. In box 3502 a transmission of reference signals is received in a subset of resource elements (REs) of a symbol, where at least some of the remaining REs of the symbol are muted and where the reference signal is received at a level of increased transmit power. In module 3504, a response message is transmitted based on the received reference signal.
FIG. 36 is a block diagram representation of a part 3600 of a wireless communication apparatus. Module 3602 is for receiving a transmission of reference signals in a subset of resource elements (RE) of a symbol, where at least some of the remaining REs of the symbol are muted and where the reference signal is received at a level of increased transmit power. Module 3604 is for transmitting a response message based on the received reference signal.
FIG. 37 is a flowchart representation of a wireless communication process 3700. Information about an aperiodic transmission resource pattern assigned to a reference signal is received at box 3702. The aperiodic transmission resource pattern has a multiple subframe periodicity. At box 3704 the reference signal is received according to the aperiodic transmission resource pattern.
FIG. 38 is a block diagram representation of a part 3800 of a wireless communication apparatus. Module 3802 is for receiving information about an aperiodic transmission resource pattern assigned to a reference signal, where the aperiodic transmission resource pattern has multiple subframe periodicity. Module 3804 is for receiving the reference signal according to the aperiodic transmission resource pattern.
FIG. 39 is a flowchart representation of a wireless communication process 3900. At box 3902 a subframe dependent pattern of transmission resources assigned to a reference signal is received, where the subframe dependent pattern varies over a plurality of subframes such that all available transmission resources are used at least once. In box 3904, a control signal of one subframe is received in a transmission resource assigned to the reference signal in another subframe of the plurality of subframes. As described above, certain subframes can prevent the transmission of reference signals when other control signals or radiolocation signals are used in certain subframes. However, in other subframes, REs can be assigned to reference signal transmissions to ensure that a channel is detected uniformly.
FIG. 40 is a block diagram representation of a part 4000 of a wireless communication apparatus. Module 4002 is for receiving a subframe dependent pattern of transmission resources assigned to a reference signal, where the subframe dependent pattern varies over the plurality of subframes such that all available transmission resources are used at least once. The module 4004 is for receiving a control signal of one subframe in a transmission resource assigned to the reference signal in another subframe of the plurality of subframes.
ES 2 586 666 T3
FIG. 41 is a flowchart representation of a wireless communication process 4100. In box 4102 a reference signal is received from a subset of resource elements (RE) in a subframe. In box 4104, at least one data transmission comprising a space-time block coding group (STBC) is received at an RE that is not in the RE subset of the subframe.
FIG. 42 is a block diagram representation of a part 4200 of a wireless communication apparatus. Module 4202 is for receiving a reference signal from a subset of resource elements (RE) in a subframe. Module 4204 is for receiving at least one data transmission comprising a space-time block coding group (STBC) in an RE that is not in the RE subset of the subframe.
FIG. 43 is a flowchart representation of a wireless communication process 4300. Box 4302 identifies a set of resource elements available in a resource block of a subframe, where the resource elements of the set of available resource elements can be used for channel status information reference signal symbols (CSI -RS). In box 4304 a subset of the set of available resource elements is selected, where the subset includes enough resource elements to allow a maximum supported number of transmit antennas. In box 4306, the subset is used to transmit one or more CSI-RS symbols to user equipment.
FIG. 44 is a block diagram representation of a part 4400 of a wireless communication apparatus. Module 4402 is for identifying a set of available resource elements in a resource block of a subframe, where the resource elements of the set of available resource elements can be used for channel status information reference signal symbols (CSI -RS). Module 4404 is for selecting a subset from the set of available resource elements, where the subset includes enough resource elements to allow a maximum supported number of transmit antennas. Module 4406 is for using the subset to transmit one or more CSI-RS symbols to user equipment.
FIG. 45 is a flowchart representation of a wireless communication process 4300. In box 4502, resources are allocated based on the number of transmitting antennas used for transmitting the reference signal, where the function is nested with respect to the number of transmitting antennas, such that a corresponding first resource pattern a first number of transmitting antennas is a superset of a second resource pattern corresponding to a second number of transmitting antennas when the first number is greater than the second number. In box 4504, the allocated resources are indicated in an allocation message. As described above, in some designs, the nested allocation methodology can be used to allocate CSI-RS transmissions to antenna ports. For example, in some designs, REs can be assigned to 8 antenna ports, which can be divided into two non-overlapping groups of REs assigned to 4 Tx antenna ports, which in turn can be divided into 2 CSI-RS transmissions of 2 Tx antenna ports. As described above with respect to FIGS. 3 at 12, the resource pattern assigned to the reference signal transmissions may not overlap with other pre-assigned resource patterns, such as CRS and UE-RS transmissions.
FIG. 46 is a block diagram representation of a part 4600 of a wireless communication apparatus. The 4602 module is provided to allocate resources based on the number of transmitting antennas used for transmitting the reference signal, where the function is nested with respect to the number of transmitting antennas, such that a first resource pattern corresponding to a first number of transmitting antennas is a superset of a second resource pattern corresponding to a second number of transmitting antennas when the first number is greater than the second number. Module 4604 is provided to indicate allocated resources in an allocation message. The allocation message may be an upper layer message and may be in the form of a bitmap specifying the REs allocated in a subframe.
It should be appreciated that several new techniques are disclosed for allocating transmission resources to a reference signal. In one aspect, the new techniques can be applied to the channel status information reference signal in LTE version 10.
It should further be appreciated that the various designs described above avoid having pairs of SFBCs separated in frequency by several tones. Some designs use STBC in combination with SFBC. Some designs introduce RE in white. Some designs use SFBC / single antenna port transmission using a default transmission (beam) scheme in some REs, while others use normal SFBC / SFBC-FSTD. For example, in some designs, the CRS ports can be used and can be switched across the RBs to ensure that all CRS ports are used equally to achieve a better balance of power.
It should further be appreciated that, in one aspect, the resource elements of a resource block are assigned to other
ES 2 586 666 T3 reference signals determined already mandatory transmissions. Of the remaining REs, which were available for data transmissions in legacy systems (eg version 8 and version 9), the REs are assigned to reference signal transmissions. In one aspect, the data REs are assigned to the reference signal so that the remaining data REs can be assigned to data transmissions using a modulation technique, such as SFBC coding, whereby at least one non-existent RE is generated. grouped into a symbol in which the REs are assigned to the reference signal.
In some disclosed designs, one cell's data REs are muted at a location used for reference signal transmissions in other cells. In one aspect, due to silencing in other cells, a reference signal transmitted in a given cell suffers less interference, thus resulting in more efficient calibration of channel characteristics.
In some disclosed designs, the pattern of REs assigned to a reference signal is periodic over a number of subframes. Periodicity can be useful to increase the power of the transmitted reference signal.
In some designs, STBC and STBC-FSTD can be used in symbols containing CSI-RS and muted tones avoiding the use of the SFBC scheme in tones that are separated in frequency by two or more tones. In one aspect, this can result in nearly identical utilization of all CRS antenna ports, and can work in all combinations of CRS, CSI-RS, and squelch patterns.
In some disclosed designs, an RE pattern is assigned to the transmission of a reference signal, out of all the possible REs available for transmission of the reference signal, based on the power class of the transmitting base station. . In one aspect, the assignment based on power class can be carried out such that REs assigned to transmitters in a different power class are orthogonal to each other in the time, frequency or code domain. Orthogonalization can allow cooperative coexistence of macro, pico, and femtoredes.
It should be further appreciated that, in some disclosed designs, REs are assigned to the transmission of a reference signal in a subframe dependent pattern, such that all possible REs are assigned according to a number of subframes, thus providing coverage. substantially uniform across the entire transmission channel bandwidth.
The specific order or hierarchy of the disclosed process steps is to be understood as an example of exemplary approaches. According to design preferences, it is to be understood that the specific order or hierarchy of steps in the processes may be reordered as long as they remain within the scope of the present disclosure. The accompanying process claims present elements of the various steps in an exemplary order and are not limited to the specific order or hierarchy presented.
Those skilled in the art will understand that the information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols and chips, which may have been mentioned throughout the above description, can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, fields or particles. optical, or any combination thereof.
The term "exemplary" is used herein in the sense that it serves as an example, instance, or illustration. Any aspect or design described herein by way of example should not necessarily be considered to be preferred or advantageous over other aspects or designs.
Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above, generally with respect to their functionality. Whether such functionality is implemented as hardware or software will depend on the particular application and the design limitations imposed on the entire system. Those skilled in the art may implement the described functionality in different ways for each particular application, but such implementation decisions should not be construed as a departure from the scope of the present disclosure.
The various illustrative logic blocks, modules, and circuits described in connection with the embodiments disclosed herein (e.g., identifiers, allocators, transmitters, and grantors) may be implemented or performed with a general-purpose processor, with a digital signal processor ( DSP), with an application-specific integrated circuit (ASIC), with a programmable field gate array (FPGA), or with another programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor can be a microprocessor, but as an alternative, the
ES 2 586 666 T3 processor can be any conventional processor, controller, microcontroller or state machine. A processor can also be implemented as a combination of computing devices, for example a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors together with a DSP core or any other such configuration.
In one or more exemplary embodiments, the described functions may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored in or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. The storage media can be any available medium that can be accessed by a computer. By way of example, and not by way of limitation, such computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to transport or store desired program code in the form of instructions or data structures and can be accessed by a computer. Discs, as used herein, include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVD), floppy discs, and Blu-ray discs, where the discs typically reproduce data magnetically or optically with laser. Combinations of the above should also be included within the scope of computer-readable media.
The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications of these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments shown herein, but is granted the broadest scope consistent with the principles and novel features disclosed herein.
Contents12
40 members in 15 offices
Priority claims11
| Document | Office | Kind | Date |
|---|---|---|---|
| 307413P | United States of America | – | |
| 30741310 | United States of America | P | |
| 307758P | United States of America | – | |
| 30775810 | United States of America | P | |
| 374556P | United States of America | – | |
| 37455610 | United States of America | P | |
| 438183P | United States of America | – | |
| 438183P | United States of America | P | |
| 201113032592 | United States of America | A | |
| 201113032592 | United States of America | – | |
| 2011025961 | United States of America | W |
Members40
| Document | Office | Kind | |
|---|---|---|---|
| CA2788994A1 | Canada | A1 | |
| WO2011106457A2 | World Intellectual Property Organization (WIPO) | A2 | |
| US2012058791A1 | United States of America | A1 | |
| WO2011106457A3 | World Intellectual Property Organization (WIPO) | A3 | |
| TW201218674A | Taiwan Province of China | A | |
| SG182820A1 | Singapore | A1 | |
| CN102845011A | China | A | |
| KR20120140247A | Republic of Korea | A | |
| EP2540022A2 | European Patent Office (EPO) | A2 | |
| JP2013520935A | Japan | A | |
| RU2012140452A | Russian Federation | A | |
| RU2530749C2 | Russian Federation | C2 | |
| JP5612132B2 | Japan | B2 | |
| KR20140130483A | Republic of Korea | A | |
| JP2015039175A | Japan | A | |
| SG10201501299VA | Singapore | A | |
| TWI505662B | Taiwan Province of China | B | |
| KR20150132883A | Republic of Korea | A | |
| EP2540022B1 | European Patent Office (EPO) | B1 | |
| BR112012020854A2 | Brazil | A2 | |
| US9407409B2 | United States of America | B2 | |
| EP3051732A1 | European Patent Office (EPO) | A1 | |
| HUE027422T2 | Hungary | T2 | |
| CA2788994C | Canada | C | |
| ES2586666T3This record | Spain | T3 | |
| CN102845011B | China | B | |
| US2016330005A1 | United States of America | A1 | |
| PH12012501609A1 | Philippines | A1 | |
| JP6092166B2 | Japan | B2 | |
| CN106850150A | China | A | |
| KR101754230B1 | Republic of Korea | B1 | |
| KR101799931B1 | Republic of Korea | B1 | |
| MY164800A | Malaysia | A | |
| MY164800A | Malaysia | A | |
| EP3051732B1 | European Patent Office (EPO) | B1 | |
| HUE045549T2 | Hungary | T2 | |
| US10594452B2 | United States of America | B2 | |
| ES2750726T3 | Spain | T3 | |
| CN106850150B | China | B | |
| BR112012020854B1 | Brazil | B1 |
Numbers
- Publication
- 2586666
- Application
- 11706449
Titles2
- Spanish
- Señales de referencia de información de estado de canal
- English
- Reference signals of channel status information
Classification
- IPC, 1
- H04L1 06