JP6952166B2 - Equipment, methods, and integrated circuits - Google Patents

Description

The present invention relates to constructing a subframe including both an uplink portion and a downlink portion in a wireless communication system, and transmitting and receiving data within such a subframe.

Long Term Evolution (LTE)
Third-generation mobile systems (3G) based on WCDMA® wireless access technology are widely deployed around the world. The first step in strengthening or evolving this technology is to introduce extended uplinks, also known as High-Speed Downlink Packet Access (HSDPA) and High-Speed Uplink Packet Access (HSUPA). It needs to be introduced and provided with highly competitive wireless access technology.

To compete for new wireless access technologies in preparation for further growth in user demand, 3GPP has introduced a new mobile communication system called Long Term Evolution (LTE). LTE is designed to meet carrier needs for high-speed data and media transfer and high-volume voice support over the next decade. The ability to provide high bit rates is an important measure of LTE.

The Long Term Evolution (LTE) work item specifications called Evolved UTRA (UMTS Terrestrial Radio Access) and UTRAN (UMTS Terrestrial Radio Access Network) have been finalized as Release 8 (LTE Release 8). .. LTE systems represent efficient packet-based radio access and radio access networks that provide full IP-based functionality with low latency and low cost. In LTE, scalable plurals such as 1.4, 3.0, 5.0, 10.0, 15.0, and 20.0 MHz are used to achieve flexible system deployment using a given spectrum. Transmission bandwidth is specified. In the downlink, it is orthogonal due to its inherent immunity to low symbol rate multipath interference (MPI), the use of cyclic prefixes (CPs), and its affinity for different transmit bandwidths. Frequency division multiplexing (OFDM) -based wireless access has been adopted. Considering the limited transmission power of the user equipment (UE), the provision of wide area coverage was prioritized over the improvement at the peak data rate, so single carrier frequency division multiple access (SC-FDMA: Single-). Carrier Frequency Division Multiple Access) based wireless access has been adopted in the uplink. LTE Release 8/9 employs many important packet radio access techniques, including MIMO (Multiple-input Multiple-output) channel transmission techniques, to achieve a highly efficient control signaling structure.

LTE Architecture The entire architecture is shown in FIG. 1 and the details of the E-UTRAN architecture are shown in FIG. The E-UTRAN consists of an eNodeB (enode B) that provides protocol termination for the E-UTRA user plane (PDCP / RLC / MAC / PHY) and control plane (RRC) for the user equipment (UE). The eNodeB (eNB) includes a user plane header compression and encryption function, including a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, and a radio link control (RLC) layer. Hosts the Packet Data Control Protocol (PDCP) layer. eNodeB also provides a radio resource control (RRC) function corresponding to the control plane. eNodeB provides radio resource management, authorization control, scheduling, enhanced quality of service (QoS) negotiated, cell information broadcasting, user plane data and control plane data encryption / decryption, and downlink / Performs many functions, including compressing / decompressing uplink user plane packet headers. The eNodeBs are interconnected to each other using the X2 interface.

In addition, eNodeB uses the S1 interface to EPC (Evolved Packet Core), more specifically, S1-MME to the Mobility Management Entity (MME), and S1-U to serve the serving gateway. Connected to (SGW). The S1 interface supports a many-to-many relationship between the MME / serving gateway and the eNodeB. The SGW serves as a mobility anchor for the user plane during handover between eNodeBs (terminating the S4 interface and relaying traffic between the 2G / 3G system and the PDN GW), and with LTE and other 3GPP statements. Routes and forwards user data packets, also acting as an anchor for mobility between. For idle user equipment, the SGW terminates the downlink data path and triggers paging when the downlink data reaches the user equipment. The SGW manages and stores the context of the user equipment, for example, the parameters of the IP bearer service and the routing information inside the network. The SGW also performs replication of user traffic in the case of lawful intercept.

The MME is the primary control node for LTE access networks. The MME is responsible for paging procedures, including tracking and resending of user equipment in idle mode. The MME is involved in the bearer activation / deactivation process and is also responsible for selecting the SGW for the user equipment during initial connection and during intra-LTE handovers including relocation of Core Network (CN) nodes. .. The MME is responsible for authenticating the user (by interacting with the HSS). Non-Access Stratum (NAS) signaling is terminated at the MME, which is also responsible for generating and allocating temporary identification information to user equipment. The MME checks the authorization of the user equipment for camping on the service provider PLMN (Public Land Mobile Network) and tightens the roaming restrictions of the user equipment. The MME is the end point in the network for encryption / integrity protection for NAS signaling and deals with security key management. Lawful interception of signaling is also supported by MME. The MME also provides a control plane function for mobility between LTE and a 2G / 3G access network with an S3 interface terminating with MME from SGSN. The MME also terminates the S6a interface towards the home HSS for roaming user equipment.

Component Carrier Structure in LTE (Release 8) 3GPP LTE (Release 8 and later) downlink component carriers are subdivided into time-frequency regions within the so-called subframe. In 3GPP LTE (Release 8 and later), each subframe is divided into two downlink slots, one of which is shown in FIG. The first downlink slot comprises a control channel area (PDCCH area) within the first OFDM symbol. Each subframe consists of a given number of OFDM symbols in the time domain (3GPP LTE, 12 or 14 OFDM symbols in Release 8 and later), and each OFDM symbol spans the entire bandwidth of the component carrier. Therefore, each OFDM symbol is composed of several modulation symbols transmitted on _{N RB} ^DL × N _SC ^{RB subcarriers, respectively.} For example, assuming a multi-carrier communication system that employs OFDM, the minimum unit of resources that can be allocated by the scheduler, as used in 3GPP LTE, is one "resource block". Physical Resource Blocks (PRBs) are N _symb ^DL consecutive OFDM symbols in the time domain (eg, 7 OFDM symbols) and N in the frequency domain, as illustrated in FIG. _{Defined as SC} ^RB contiguous subcarriers (eg, 12 subcarriers for component carriers). In 3GPP LTE (Release 8), therefore, a physical resource block consists of one slot in the time domain and N _symb ^DL x N _SC ^RB resource elements corresponding to 180 kHz in the frequency domain (downlink resource). For further details of the grid, see, for example, Non-Patent Document 1, available at http://www.3gpp.org, which is incorporated herein by reference).

One subframe consists of two slots. When the so-called "normal" CP (cyclic prefix) is used, there are 14 OFDM symbols in the subframe, and when the so-called "extended" CP is used, in the subframe. There are 12 OFDM symbols. For terminology, in the following, _{time frequency resources equal to the same N SC} ^RB contiguous subcarriers over a complete subframe are referred to as "resource block pairs", "RB pairs" or "PRB pairs". ..

The term "component carrier" refers to a combination of several resource blocks in the frequency domain. In future releases of LTE, the term "component carrier" will not be used and instead the term will be changed to "cell", which refers to a combination of downlink resources and optionally uplink resources. The link between the carrier frequency of the downlink resource and the carrier frequency of the uplink resource is shown in the system information transmitted over the downlink resource.

Similar assumptions about the component carrier structure apply to later releases.

Time Division Duplex-TDD
LTE is a frequency division duplex (FDD) mode and time division duplex (FDD) within a matching framework designed to support the evolution of TD-SCDMA (Time-Division Synchronous Code Division Multiple Access). It can operate in TDD: Time Division Duplex) mode. TDD separates uplink and downlink transmissions in the time domain, but the frequencies may be the same.

The term "duplex" refers to two-way communication between two devices, unlike unidirectional communication. In the bidirectional case, transmissions on the link in each direction may occur simultaneously (“full duplex”) or at mutually exclusive times (“half duplex”). ..

In the case of TDD in the unpaired radio spectrum, the basic structure of RB and RE is shown in FIG. Only a subset of the radio frame subframes are available for downlink transmission and the remaining subframes are used for uplink transmission or special subframes. The special subframe is important to allow the uplink transmission timing to be advanced to ensure that the transmission signal (ie, uplink) from the UE arrives at the eNodeB at about the same time. The signal propagation delay is related to the distance between the transmitter and receiver (ignoring reflections and other similar effects). This means that the signal transmitted by the UE closer to the eNodeB travels for a shorter time than the signal transmitted by the UE farther away from the eNodeB. To reach at the same time, the distant UE must send its signal faster than the near UE. It is solved by the so-called "timing advance" procedure in the 3GPP system. In TDD, transmission and reception occur on the same carrier frequency. That is, there are additional situations in which downlinks and uplinks need to be duplicated in the time domain. A UE far from the eNodeB needs to start uplink transmission earlier than a UE near the eNodeB. On the other hand, the downlink signal is received by the UE closer to the eNodeB earlier than the UE farther from the eNodeB. A guard time is defined within the special subframe to allow the circuit to switch from DL reception to UL transmission. To manage the timing advance problem, the guard time for the distant UE needs to be longer than the guard time for the near UE.

FIG. 4 specifically shows a switching point periodicity of 5 ms, i.e., frame structure type 2 for TDD configurations 0, 1, 2, and 6. In particular, FIG. 4 shows a radio frame that is 10 ms in length and two corresponding half frames, each 5 ms. The radio frame is composed of 10 subframes, each of which is 1 ms. Each of the subframes is defined by one of the uplink-downlink configurations according to the table of FIG. 5, and is assigned an uplink (U), downlink (D), or special (S) type.

This TDD structure is known as "Frame Structure Type 2" in 3GPP LTE Release 8 and later, and seven different uplink-downlink configurations have been defined since 3GPP LTE Release 8 and they vary. Allows downlink-uplink ratio and switching periodicity. FIG. 5 shows a table with seven different TDD uplink-downlink configurations indexed from 0-6. "D" indicates a downlink subframe, "U" indicates an uplink subframe, and "S" indicates a special subframe. These configurations differ from each other depending on the number and position of uplink (U) and downlink (D) subframes and special subframes (S) for downlink-uplink switching in TDD operation. As you can see, the seven available TDD uplink-downlink configurations (for simplicity, some of the special subframes are available for downlink transmission, so the special subframes are downlink subframes. When counting as, it can provide between 40% and 90% of the downlink subframes.

As can be seen from FIG. 5, subframe # 1 (“#” means “number”) is always a special subframe, and subframe # 6 is in some cases a special subframe, ie, TDD configuration 0. Special subframes for 1, 2, and 6. On the other hand, in the case of TDD configurations 3, 4, and 5, subframe # 6 is for downlink. The remaining subframes are uplink subframes or downlink subframes.

The special subframe includes three fields: DwPTS (Downlink Pilot Time Slot), GP (Guard Period), and UpPTS (Uplinl Pilot Time Slot). They are used to separate the uplink subframes and the downlink subframes. In special subframes, the uplink and downlink signals may be transmitted within the subframe fields UpPTS and DwPTS, respectively. They are separated by a guard period, also known as the downlink-uplink switching point. Uplink and downlink capacitance within this anomalous subframe S is reduced compared to regular subframes, providing less bit forward error correction redundancy for a given transport block size. It means that it can be used, or that the transport block size itself should be reduced.

FIG. 6 shows a table relating to special subframe settings. Specifically, FIG. 6 lists the lengths of DwPTS and UpPTS, with the number of downlink symbols Nd and the number of uplink symbols Nu defined for 3GPP LTE release 11. When 3GPP defines the length of DwPTS and UpPTS as multiples of sampling frequency (Ts), they represent the number of OFDM symbols or SC-FDMA symbols contained in DwPTS and UpPTS, respectively. For example, in the special subframe setting # 1, the DwPTS length, which normally assumes a cyclic prefix, is defined as 6592 Ts. In the case of a typical cyclic prefix, the lengths of the first and seventh OFDM symbols are 2208 Ts, respectively, and the other symbols are 2192 Ts. Therefore, the length of DwPTS of 6592Ts is equal to Nd = 3 OFDM symbol: (2208 + 2192 + 2192) Ts = 6592Ts. The GP (guard period) can be derived by subtracting the lengths of the associated DwPTS and UpPTS from the length (eg, 14) of the special subframe (in the number of symbols or multiples of Ts). Since the special subframe setting is independent of the uplink-downlink configuration shown in FIG. 5, all combinations of these two configurations are possible.

The special subframe settings in the table of FIG. 6 can take values 0-9, each of which is associated with a particular configuration of the number of uplink and downlink symbols. The number of uplink symbols and downlink symbols also depends on the length of the applied uplink and downlink cyclic prefixes. As can be seen from the table, the length of the uplink portion (UpPTS) of the special subframe is very low and can only take one or two symbols. Therefore, UpPTS is only used to transmit uplink signals such as reference signals or random access requests in the form of access preambles.

TDD configurations applied within the system include mobile stations and bases such as Radio Resource Management (RRM) measurements, Channel State Information (CSI) measurements, channel estimation, PDCCH detection, and HARQ timing. Affects many actions performed by the station. Specifically, the UE is in which subframe for TDD configuration within the current cell, ie measurement, CSI measurement and reporting, time domain filtering to obtain channel estimates, PDCCH detection, or UL / DL ACK / NACK feedback. Read system information to know what to monitor.

Logical Channel and Transport Channel The MAC layer provides data transfer services for the RLC layer over the logical channel. The logical channel is either a control logical channel that carries control data such as RRC signaling, or a traffic logical channel that carries user plane data. Broadcast Control Channel (BCCH), Paging Control Channel (PCCH), Common Control Channel (CCCH), Multicast Control Channel (MCCH), and DCCH. : Dedicated Control Channel) is a control logical channel. The dedicated traffic channel (DTCH: Dedicated Traffic Channel) and the multicast traffic channel (MTCH: Multicast Traffic Channel) are traffic logical channels.

Data from the MAC layer is exchanged with the physical layer via the transport channel. Data is multiplexed into transport channels depending on how they are transmitted wirelessly. Transport channels are classified as downlinks or uplinks as follows: Broadcast Channel (BCH), Downlink Shared Channel (DL-SCH), Paging Channel (PCH). , And the multicast channel (MCH: Multicast Channel) is the downlink transport channel, and the uplink shared channel (UL-SCH: Uplink Shared Channel) and the random access channel (RACH: Random Access Channel) are the uplink transport channels. be.

Multiplexing is then performed between the logical and transport channels on the downlink and uplink, respectively.

Layer 1 / Layer 2 (L1 / L2) Control Signaling Gives scheduled users allocation status, transport formats, and other data-related information (eg, HARQ information, Transmit Power Control (TPC) commands). L1 / L2 control signaling is transmitted over the downlink with the data to inform. The L1 / L2 control signaling is multiplexed with the downlink data within the subframe, assuming that the user allocation can change from subframe to subframe. User allocation may be performed on a TTI (Transmission Time Interval) basis, and the length of the TTI can be a multiple of the subframe. The length of the TTI may be fixed within the service area for all users, may be different for different users, and may be dynamic for each user. In general, L1 / 2 control signaling only needs to be transmitted once per TTI. In LTE Release 8, the TTI is 1 ms, which corresponds to one subframe.

TTI is a parameter in UMTS and LTE (and other digital telecommunications networks) related to encapsulation of data from higher layers for transmission on the wireless link layer. TTI is also related to the size of the data block passed from the upper network layer to the wireless link layer. In particular, the TTI determines the timing and particle size of mapping data to the physical layer. One TTI is the time interval at which a given data is mapped to the physical layer.

The L1 / L2 control signaling is transmitted on the Physical Downlink Control Channel (PDCCH). The PDCCH most often carries the message as Downlink Control Information (DCI), which includes resource allocation and other control information for a group of mobile terminals or UEs. In general, several PDCCHs can be transmitted within one subframe. In 3GPP LTE, an allocation for uplink data transmission, which is also called an uplink scheduling grant or an uplink resource assignment, is also transmitted on the PDCCH.

In general, information transmitted over L1 / L2 control signaling for allocating uplink or downlink radio resources (particularly LTE (-A) Release 10) can be classified into the following items:
-User identity that indicates the assigned user. This is usually included in the checksum by masking the CRC with user information.
-Resource allocation information indicating the resource (Resource Block, RB: Resource Block) allocated by the user. Note that the number of RBs assigned by the user can be dynamic.
A carrier indicator used when the control channel transmitted on the first carrier allocates resources for the second carrier, i.e., resources on the second carrier or resources associated with the second carrier.
-Modulation and coding scheme that determines the modulation scheme and coding rate to be adopted.
HARQ information such as a new data indicator (NDI) and / or a redundant version (RV) that is particularly useful in retransmission of data packets or parts thereof.
A power control command that adjusts the transmit power of the transmission of assigned uplink data or control information.
• Reference signal information, such as the applied cyclic shift and / or quadrature covercode index, that should be adopted for the transmission or reception of the reference signal associated with the allocation.
-Uplink or downlink allocation index used to identify the order of allocation, especially useful within the TDD system.
• Hopping information, eg, instructions on whether and how to apply resource hopping to increase frequency diversity.
• A CSI request used to trigger the transmission of channel state information within the allocated resource.
A flag used to indicate and control whether transmission occurs in a single cluster (a set of consecutive RBs) or in multiple clusters (at least two non-continuous sets of consecutive RBs). , Multi-cluster information. Multi-cluster allocation was introduced with 3GPP LTE- (A) Release 10.

It should be noted that the above list is not exhaustive depending on the DCI format used and not all mentioned information items need to be present within each PDCCH transmission.

Downlink control information occurs in several formats that differ in overall size and the information contained in its fields. The various DCI formats currently defined for LTE are as follows and are available in non-Patent Document 2 (available at http://www.3gpp.org and incorporated herein by reference). It is described in detail. For more information on the DCI format and specific information transmitted within the DCI, see Chapter 9.3 of Technical Standards or Non-Patent Document 3, which is incorporated herein by reference.

Error detection is provided by a 16-bit CRC (ie, DCI) attached to each PDCCH so that the UE can identify whether it has received the PDCCH transmission correctly. Furthermore, it is necessary for the UE to be able to identify which PDCCH is directed to the UE. This can theoretically be achieved by adding an identifier to the PDCCH payload, but it is more efficient to scramble the CRC with "UE identity", thereby saving additional overhead. NS. The CRC parity bit may be calculated using the entire payload. Parity bits are calculated and added. If the UE transmit antenna selection is not configured or applicable, the CRC parity bit is scrambled with the corresponding RNTI after addition.

Scramble may further depend on UE transmit antenna selection. If the UE transmit antenna selection is configured and applicable, after addition, the CRC parity bits are scrambled with the antenna selection mask and the corresponding RNTI. In both cases, RNTI is involved in the scrambling operation.

Correspondingly, the UE descrambles the CRC by applying the "UE identification information", and if no CRC error is detected, the UE determines that the PDCCH carries its control information towards itself. The terms "masking" and "demasking" are also used in the case of the above-mentioned process of scrambling the CRC with identification information.

The above-mentioned "UE identification information" in which the CRC of DCI may be scrambled may also be SI-RNTI (System Information Radio Network Temporary Identifier). SI-RNTI is not such "UE identification information" but the type of information indicated and transmitted, in this case the identifier associated with the system information. SI-RNTI is usually fixed in the specification and is known to all UEs in advance.

In general, the uplink control data in LTE is on the physical uplink shared channel (PUSCH) in the so-called uplink control information (UCI) or the physical uplink control channel (PUCCH: Physical Uplink Control). It is transmitted together with the user data on Channel). UCI
− Scheduling request
− ACK / NACK of HARQ responding to downlink data packets on PDSCH
-Channel State Information (CSI) including Channel Quality Indicator (CQI) and / or Rank Indicator (RI) associated with MIMO transmission and / or Precoding Matrix Indicator (PMI).
At least one of them is provided.

For more information on the UCI format and specific information transmitted within the UCI, see Chapter 16.3 of Technical Standards or Non-Patent Document 3, which is incorporated herein by reference.

Physical Downlink Control Channel (PDCCH) and Physical Downlink Sharing Channel (PDSCH)
The physical downlink control channel (PDCCH) carries, for example, scheduling permissions to allocate resources for downlink or uplink data transmission. Multiple PDCCHs can be transmitted within one subframe.

_{PDCCH for user equipment is the first N symb} ^PDCCH OFDM symbols in a subframe that span the entire system bandwidth (usually one, two, or three OFDM symbols, as indicated by PCFICH, exceptions. In such cases, it is transmitted on (one of two, three, or four OFDM symbols) as indicated by PCFICH. System bandwidth is typically comparable to the span of cells or component carriers. _{The region occupied} by the first N ^{symb PDCCH} OFDM symbols in the time domain and the N _RB ^DL × N _SC ^RB subcarriers in the frequency domain is also referred to as the PDCCH region or control channel region. _{The remaining N symb} ^PDSCH = 2 · N _symb ^DL −N _symb ^PDCCH OFDM symbols in the time domain _{or N RB} ^DL × N _SC ^RB subcarriers in the frequency domain are called the PDSCH region or shared channel region ( See below).

For downlink grants (ie, resource allocation) on a physical downlink shared channel (PDSCH), the PDCCH allocates PDSCH resources to (user) data within the same subframe. The PDCCH control channel region within a subframe consists of a set of CCEs in which the total number of CCEs within the control region of the subframe is distributed across time and frequency control resources. Multiple CCEs can be combined to effectively reduce the code rate of the control channel. CCEs are combined in a predetermined manner using a tree structure to achieve different code rates.

At the transport channel level, the information transmitted via the PDCCH is also referred to as L1 / L2 control signaling (see above for details on L1 / L2 control signaling).

There is a specific predefined timing relationship between the uplink resource allocation received within the subframe and the corresponding uplink transmission within the PUSCH. Details are given in Section 8.0 of Non-Patent Document 4, which is incorporated herein by reference. Specifically, Table 8-2 of TS36.213 defines the parameter k for TDD configurations 0-6. Here, k indicates the positive offset of the target of the uplink resource allocation received within the subframe, and for TDD configuration 0, the uplink subframes 3 and 8 are omitted here for simplicity. There is an additional definition of timing for. For example, the parameter k is 6 in the case of the subframe 1 of the TDD configuration 1, and the uplink resource allocation received in the subframe 1 of the TDD configuration 1 is actually the uplink subframe of the TDD configuration 1. It means that it is for subframe 1 + 6 = 7.

Hybrid ARQ Method A common technique for error detection and correction in packet transmission systems on unreliable channels is called a hybrid automatic repeat request (HARQ). A hybrid ARQ is a combination of forward error correction (FEC) and ARQ.

If an FEC-encoded packet is transmitted and the receiver cannot correctly decode the packet (errors are usually checked by a CRC (Cyclic Redundancy Check)), the receiver requests the packet to be retransmitted. Generally (and throughout this document), the transmission of additional information is referred to as "retransmission (of the packet)". However, this retransmission does not necessarily mean the transmission of the same encoded information, but may also mean the transmission of arbitrary information belonging to the packet (eg, additional redundancy information).

The following hybrid ARQ schemes are defined according to the information (generally, sign bits / symbols) of which transmissions are configured and how the receiver processes the information.

In the Type I HARQ method, if the receiver cannot correctly decode the packet, the encoded packet information is discarded and retransmission is required. This means that all transmissions are decrypted separately. Generally, retransmissions include the same information (sign bit / symbol) for the first transmission.

In the Type II HARQ method, if the receiver cannot correctly decode the packet, retransmission is required, and the receiver uses the (erroneously received) encoded packet information as soft information (soft bits / symbols). Store. This means that a soft buffer is required at the receiver. The retransmission can consist of the same, partially identical, or non-identical information (sign bit / symbol) according to the same packet as the previous transmission. Upon receiving the retransmission, the receiver synthesizes the information stored from the soft buffer with the information just received and attempts to decode the packet based on the synthesized information. (The receiver may attempt to decode the transmissions individually, but synthesizing the transmissions generally improves performance.) Transmission synthesizing refers to so-called soft synthesizing, where multiple received sign bits / symbols are likely. The sign bit / symbol received independently is code-synthesized. Common methods for soft synthesis are Maximum Ratio Combining (MRC) and Log Likelihood Ratio (LLR) synthesis (LLR synthesis is only for the sign bit). It works).

The Type II method is more sophisticated than the Type I method because the probability of correct reception of a packet increases with each retransmission received. This increase occurs at the expense of the hybrid ARQ softbuffer required at the receiver. This method can be used to perform dynamic link adaptation by controlling the amount of information to be retransmitted. For example, if the receiver detects that the decryption is "almost" successful, the receiver receives a small portion of the information for the next retransmission to be transmitted (a smaller number of sign bits / symbols than the previous transmission). Can only be requested. In this case, more theoretically, it may not be possible to correctly decode the packet solely by considering this retransmission by itself (non-self-decryptable retransmission).

The Type III HARQ scheme may be considered as a subset of the Type II scheme. In addition to the Type II method requirements, each transmission in the Type III method must be self-decryptable.

Synchronous HARQ means that retransmissions of HARQ blocks occur at pre-defined periodic intervals. Therefore, no explicit signaling is required to indicate the retransmission schedule to the receiver.

Asynchronous HARQ provides the flexibility to schedule retransmissions based on air interface conditions. In this case, some identification of the HARQ process needs to be signaled to allow correct synthesis and protocol operation. In the 3GPP LTE system, HARQ operation with 8 processes is used. The HARQ protocol behavior for downlink data transmission is similar to, or even identical to, HSDPA.

The uplink HARQ protocol operation has two different options for how to schedule retransmissions. Retransmissions are either "scheduled" by NACK (also known as synchronous non-adaptive retransmission) or explicitly scheduled by the network by transmitting PDCCH (also known as synchronous adaptive retransmission). For synchronous non-adaptive retransmissions, retransmissions use the same parameters as the previous uplink transmission. That is, retransmissions are signaled on the same physical channel resource, each using the same modulation scheme / transport format.

Since synchronous adaptive retransmissions are explicitly scheduled via PDCCH, eNodeB may change certain parameters for retransmissions. Retransmissions can be scheduled, for example, on different frequency resources to avoid fragmentation on the uplink. Alternatively, the eNodeB can instruct the user equipment to change the modulation scheme or, as an alternative, which redundant version to use for retransmission. It should be noted that HARQ feedback (ACK / NACK) and PDCCH signaling occur at the same time. Therefore, the user equipment only needs to check once whether a synchronous non-adaptive retransmission is triggered (ie, only NACK is received) or whether the eNodeB requests a synchronous adaptive retransmission (ie, PDCCH is signaled). It's fine.

HARQ and control signaling for TDD operation As described above, the transmission of downlink or uplink data by HARQ is an acknowledgment ACKnowledgement (ACK or ACK or) to inform the sender of the success or failure of packet reception. NACK (Negative ACK)) needs to be transmitted in the opposite direction.

For FDD operation, the acknowledgment indicator associated with data transmission within subframe n is transmitted in the opposite direction during subframe n + 4. As a result, there is a one-to-one synchronous mapping between when the transport is transmitted and the corresponding acknowledgment. However, in the case of TDD operation, subframes are specified as uplinks or downlinks or specials (see next chapter) on a cell-specific basis. This limits the amount of time resource grants, data transmissions, acknowledgments, and retransmissions can be sent in their respective directions. Therefore, the LTE design for TDD supports grouped ACK / NACK transmissions to carry multiple acknowledgments within a single subframe.

In the case of uplink HARQ, the transmission of multiple acknowledgments (within a single downlink subframe) on the Physical Hybrid ARQ Indicator Channel (PHICH) is simple from the perspective of eNodeB. This is not a problem as it is not significantly different from the case where one acknowledgment is sent to multiple UEs at the same time. However, in the case of downlink HARQ, the FDD uplink control signaling (PUCCH) format is insufficient to carry additional ACK / NACK information when the asymmetry is downlink biased. Each of the TDD subframe configurations in LTE (see below and FIG. 5) has its own mapping between the downlink subframe and the uplink subframe for HARQ purposes. Designed to achieve a balance between acknowledgment delay minimization and ACK / NACK distribution across available uplink subframes. Further details are provided in Section 7.3 of Non-Patent Document 4, which is incorporated herein by reference.

Section 10.1.3 of Non-Patent Document 4, which is incorporated herein by reference, describes a TDD HARQ-ACK feedback procedure. Table 10.1.3-1 of TS36.213 provides downlink association set indexes for ACK / NACK / DTX responses to subframes of radio frames. Here, the numbers in the TDD configuration box indicate the negative offset of the subframe to which the HARQ feedback is transported within said subframe. For example, the subframe 9 for TDD configuration 0 transports the HARQ feedback of subframe 9-4 = 5, and the subframe 5 for TDD configuration 0 is actually a downlink subframe (see FIG. 5). ..

In HARQ operation, the eNB can transmit a different coded version from the original TB in retransmission. As a result, the UE can adopt IR (Incremental Redundancy) synthesis to obtain an additional coding gain with respect to the composite gain. However, in a realistic system, the eNB can transmit TB to one specific UE on one resource segment, but the UE detects the data transmission due to the loss of DL control information. I can't. In this case, IR synthesis has very poor performance for decoding retransmissions because systematic data is not available in the UE. To alleviate this problem, the UE feeds back a third state, discontinuous transmission (DTX) feedback, to TB on the associated resource segment (unlike NACK, which indicates a decryption failure). Must be shown that is not detected.

As can be seen from FIG. 5, some uplink / downlink configurations are asymmetric. For example, configuration 5 includes only one uplink subframe and eight downlink subframes. Such configurations are sometimes referred to as heavy downlinks. They can result in relatively high latency caused by the limited resources to send ACK / NACK feedback on the uplink corresponding to the transmitted downlink data. The latency is due to the lack of opportunity for uplink data. In such cases, two or more ACK / NACK feedback responses are bundled by applying a logical AND. As a result, ACK is sent only if all acknowledgments in the bundle are affirmative, otherwise the entire bundle is retransmitted. This generally results in more retransmissions and can therefore increase latency.

3GPP TS36.211, V8.9.0, "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)", section 6.2 3GPP TS36.212, V12.7.0, "Multiplexing and channel coding", section 5.3.3.1 "LTE-The UMTS Long Term Evolution- From Theory to Practice", Edited by Stefanie Sesia, Issam Toufik, Matthew Baker, Wiley, 2011 3GPP TS36.213, V12.8.0, "Physical layer procedures (Release 11)"

One non-limiting and exemplary embodiment provides devices and methods for the efficient transmission and reception of data within a special subframe that includes both downlink and uplink portions.

According to an embodiment, a device for transmitting data in a frame having subframes of a wireless communication system is provided, and each subframe contains an uplink subframe containing an uplink signal and a downlink containing a downlink signal. A subframe, or a special subframe that includes a downlink signal portion and an uplink signal portion, and the device sets a special subframe that specifies the length of the uplink and / or downlink portion of the special subframe. A receiver that receives a control signal including It comprises a transmitter and i) the length of the second TTI for mapping to the uplink portion of the special subframe is shorter than the first TTI for mapping to the uplink subframe, or ii). The first number of TTIs mapped to the uplink subframe is greater than the second number of TTIs to map to the uplink portion of the special subframe.

According to an embodiment, a device for receiving data in a frame having subframes of a wireless communication system is provided, and each subframe includes an uplink subframe accommodating an uplink signal and a downlink accommodating a downlink signal. A subframe, or a special subframe that includes a downlink signal portion and an uplink signal portion, and the device sets a special subframe that specifies the length of the uplink and / or downlink portion of the special subframe. A transmitter that transmits control signals including, a receiver that receives data mapped to special subframes according to special subframe settings, and user data and / or user data within a transmission time interval (TTI) from one subframe. A mapper for demapping control data including feedback information is provided, and i) the length of the second TTI for mapping to the uplink portion of the special subframe is the first for mapping to the uplink subframe. The first number of TTIs that are shorter than the TTI of, or ii) mapped to the uplink subframe, is greater than the second number of TTIs that map to the uplink portion of the special subframe.

According to an embodiment, a method of transmitting data in a frame having subframes of a wireless communication system is provided, and each subframe contains an uplink subframe containing an uplink signal and a downlink containing a downlink signal. A subframe, or a special subframe that includes a downlink signal portion and an uplink signal portion, and the method is a special subframe setting that specifies the length of the uplink and / or downlink portion of the special subframe. A step of receiving a control signal including, a step of mapping control data including user data and / or feedback information within a transmission time interval (TTI) into one subframe, and a step of transmitting the mapped data. Has i) the length of the second TTI for mapping to the uplink portion of the special subframe is shorter than the first TTI for mapping to the uplink subframe, or ii) uplink subframe The first number of TTIs mapped to is greater than the second number of TTIs to map to the uplink portion of the special subframe.

According to an embodiment, a method for receiving data in a frame having subframes of a wireless communication system is provided, and each subframe contains an uplink subframe containing an uplink signal and a downlink containing a downlink signal. A subframe, or a special subframe that includes a downlink signal portion and an uplink signal portion, and the method is a special subframe setting that specifies the length of the uplink and / or downlink portion of the special subframe. Includes user data and / or feedback information within the transmission time interval TTI from one subframe, including the step of transmitting a control signal including, and the step of receiving data mapped to a special subframe according to the special subframe setting. It has a step of demapping control data, and i) the length of the second TTI for mapping to the uplink portion of the special subframe is greater than the length of the first TTI for mapping to the uplink subframe. Short or ii) The first number of TTIs mapped to the uplink subframe is greater than the second number of TTIs to map to the uplink portion of the special subframe.

The above and other objects and features of the present invention, along with the accompanying drawings, will become more apparent from the following description and preferred embodiments.

It is a block diagram which shows the exemplary architecture of a 3GPP LTE system. It is a block diagram which shows an exemplary outline of the whole E-UTRAN architecture of 3GPP LTE. FIG. 6 is a schematic diagram showing an exemplary downlink resource grid of downlink slots defined for 3GPP LTE (Release 8/9 and later). FIG. 5 is a schematic diagram showing the structure of a radio frame composed of 10 subframes for a switching point periodicity of 5 ms. It is a table showing the definitions of each of the seven currently standardized (static) TDD UL / DL configurations 0-6, 10 subframes and their switching point periodicity. It is a table showing possible special subframe settings. It is a block diagram which shows the device for transmitting and receiving data using various configurations of a special subframe, and is This is an exemplary table of special subframe settings. This is an exemplary table of special subframe settings. This is an exemplary table of special subframe settings. It is the schematic which shows the structure of the special subframe. It is the schematic which shows two examples of the mapping of the transmission time interval to a special subframe. It is the schematic which shows four examples of the mapping of the transmission time interval to the uplink subframe and the downlink subframe. It is a table which shows the structure of the uplink and the downlink including the additional special subframe. It is a table which shows the structure of the uplink and the downlink including the additional special subframe. It is a table which shows the structure of the uplink and the downlink including the additional special subframe. It is a table which shows the structure of the uplink and the downlink including the additional special subframe. It is a table which shows the structure of the uplink and the downlink including the additional special subframe. It is a table which shows the structure of the uplink and the downlink including the additional special subframe. It is a table which shows the structure of the uplink and the downlink including the additional special subframe. It is a table which shows the structure of the uplink and the downlink including the additional special subframe. It is a flow chart which shows the receiving method and transmission method.

As shown in FIG. 6, the uplink portion (UpPTS) of the special subframe can have only one or two symbols. For LTE, these symbols are SC-FDMA symbols. One or two symbols may be used to transmit some reference signals (eg, sounding reference signals, SRS), but are insufficient to accommodate control or user data. For example, this short uplink portion is not sufficient to support PUSCH transmission (user data) or control data transmission including feedback information such as acknowledgments (ACK / NACK) or channel quality information. .. In other words, even when puncturing is applied, the data and control signals provided to map to the physical layers within a single uplink TTI may be too long to be contained in a special subframe.

However, especially when the asymmetry between the downlink capacity and the uplink capacity is high, it is possible to use the additional capacity of the special subframe for transmitting control data or user data, especially to improve the uplink capacity. Should be beneficial. For example, as can be seen in FIG. 5, in a heavy downlink configuration such as configuration 5, the uplink subframes are transmitted only once per frame. This can result in longer feedback latency for concurrent downlink traffic. Moreover, there may be insufficient resources to send feedback. As a result, acknowledgment bundling or multiplexing is applied. However, applying bundling or multiplexing can increase the loss of feedback. It contributes to increased waiting time on the other side. This loss can occur, for example, when only one joint feedback bit needs to transmit the ACK / NACK state to the two transport blocks. It is more harmful to mistakenly omit NACK compared to ACK, so in that case the joint feedback bits should indicate ACK, such joint feedback bits unless ACK is determined for both transport blocks. Should indicate NACK.

It is desirable to match the transmission structure to traditional TDD subframes in order to maintain backward compatibility with existing systems and / or avoid interference issues. In particular, uplink / downlink subframe allocation, switching periodicity, and special subframe structure should be maintained.

According to the present disclosure, special subframes may be used to reduce latency.

This may be achieved in conjunction with adopting a short transmission time interval (sTTI: short TTI), i.e., a TTI shorter than the length of the subframe. Specifically, in LTE, the TTI usually has a length of 1 ms, which corresponds to the length of the subframe. Accordingly, a single TTI is usually mapped to a single subframe. In the short TTI, the data may also be mapped separately to the respective uplink and downlink parts of the special subframe. Short TTI also reduces latency.

Better latency than previous generation 3GPP Radio Access Technology (RAT) was one performance metric that guided LTE design. Packet data latency is not only important for the perceived responsiveness of the system, it is also a parameter that indirectly affects throughput. HTTP / TCP is the dominant application layer and transport layer protocol suite used on the Internet today. The typical size of HTTP-based transactions on the Internet ranges from tens of kilobytes to 1 megabyte. Within this size range, the TCP slow start period is most of the entire transport period of the packet stream. Performance is limited by latency during TCP slow start. Therefore, improving latency can improve the average throughput for these types of TCP-based data transactions. In addition, in order to achieve very high bitrates (within Gbps in Release 13CA), the UE's L2 buffer needs to be sized accordingly. The longer the round trip time, the larger the buffer needs to be. The only way to reduce buffering requirements on the UE and eNB sides is to reduce latency.

Radio resource efficiency can also be positively impacted by reduced latency. Lowering the packet data latency can increase the number of possible transmission attempts within a certain delay range. Therefore, a higher BLER goal can be used for data transmission, freeing up radio resources, but still maintaining the same level of robustness for users with inadequate radio conditions. Keeping the same BLER goal, increasing the number of possible transmissions within a particular delay range can also translate into more robust transmissions of real-time data streams (eg VoLTE). This should improve the capacity of the VoLTE voice system.

The waiting time can be reduced by shortening the TTI and reducing the processing time. Specifically, the TTI length between 0.5 ms and one OFDM / SC-FDMA symbol affects reference signals and physical layer control signaling, as well as backwards compatibility, ie, from previous releases on the same carrier. It can be beneficial to take into account that it enables normal operation of the UE.

According to the present disclosure, shorter TTIs are used to map user or control data to the uplink or downlink portion of the special subframe. The short TTI is shorter than the duration of the subframe. In particular, the short TTI may correspond to (or be equal to) or be shorter than the duration of the downlink or uplink portion of the special subframe.

To further provide the possibility of mapping data to the uplink (and / or downlink) parts of the special subframe, the structure of the special subframe has been modified over the traditional special subframe (see Figure 6). Will be done.

FIG. 7 shows communication between a base station (eNB) and a terminal (user equipment, UE). The terminal may include a device 700B for transmitting data within a frame having a subframe of the wireless communication system. The wireless communication system may be an LTE system that can operate as a cellular network and / or in device-to-device mode. The frame may then correspond to a radio frame currently defined to include the 10 subframes described above with reference to FIG. Each such subframe is either an uplink subframe containing an uplink signal, a downlink subframe containing a downlink signal, or a special subframe containing a downlink signal portion and an uplink signal portion. ..

In the uplink direction, the terminal (UE) transmits data to the base station. In the downlink direction, the terminal receives data from the base station. The data may be user data (ie, data generated by a user application that may include control overhead in higher layers) or control data such as layer 1 / layer 2 signaling that includes feedback information. Feedback information may include HARQ affirmative or negative acknowledgments, channel quality indications, rank indicators, or PMIs.

Note that the same device may be implemented within a relay node that communicates with the base station over the backhaul link.

The device 700B includes a receiving unit 720 and a transmitting unit 740. The receiver and transmitter can embody the functions required to receive and transmit data, such as antennas and amplifiers, which are implemented in dedicated or programmable circuits (hardware), for example.

The receiving unit 720 receives a control signal including a special subframe setting that specifies the length of the uplink portion and / or the downlink portion of the special subframe. The control signal may be a control signaling transmitted on any layer. For example, the control signal may be received via cell broadcast within the system information block. The control signal may be supplied semi-statically via a dedicated RRC protocol or via an L1 / L2 control signal such as DCI in LTE. The control signal can be valid for a single UE or for a group of UEs that includes all UEs in the cell.

Transmitting a control signal via cell broadcast, such as within an LTE system information block, has the advantage of being able to convey information to multiple receivers with low relative overhead. This is particularly advantageous for cells where all UEs are expected to behave in the same way, as far as the scope of the invention is concerned. For example, small cells, i.e. cells with a small coverage area and / or a small number of connected UEs, can be beneficial in such a manner. Transmitting the control signal via a dedicated RRC message has the advantage that the receiving unit can confirm that the control signal has been correctly received and processed. Therefore, this is advantageous if asynchronous operation due to errors should be avoided, especially when the configuration transmitted by the control signal is not expected to change on a time scale of up to 320 subframes. Transmitting control signals via L1 / L2 control signals has the main advantage of being able to quickly adapt the configuration to ad hoc needs such as highly variable traffic changes due to the data traffic model. Have. Such L1 / L2 control signals are further advantageous to a group of UEs identified by a common RNTI (Radio Network Temporary Identifier), which is applied in a manner similar to the support for dynamic TDD reconstruction messages in LTE. (See 3GPP TS36.213, v12.8.0, Section 13.1). The use of dedicated RRC messages and L1 / L2 control signals has advantages for large cells, i.e., when supporting a wide area or a large number of connected UEs. In such cases, especially in TDD, UEs near the center of the cell and UEs near the edges of the cell face large propagation delays, and as a result their timing advance offsets that compensate for the propagation delays need to be different. .. As a result, UEs closer to the cell edge may require a longer GP than UEs closer to the cell center, so that UEs closer to the cell center are generally closer to the cell edge. It should be allowed to have a length of DwPTS + UpPTS (uplink portion and / or downlink portion of the special subframe) longer than the UE.

The special subframe setting is advantageously one of a set of predefined configurations. These configurations within the set may differ in the length of the uplink, downlink, and / or guard periods between them. For example, in LTE, the special subframe has a length of 14 symbols, and the subframe configuration indicates which symbols are assigned to the uplink portion, downlink portion, and GP. Note that for some scenarios configurations with a GP with a zero symbol (ie, there is no GP between the last symbol in the downlink portion and the first symbol in the uplink portion) can also be considered. .. In particular, if the GP is shorter than one symbol, some or all of the cyclic prefixes of the first symbol of the uplink portion may be used to accommodate the timing advance offset. That is, the UE may be allowed to omit the transmission of some of the samples that make up its cyclic prefix.

The received special subframe settings are then applied by the device. For example, the controller 735 sets the device 700B according to the special subframe setting.

The device 700B further includes a mapper 730 that maps control data, including user data and / or feedback information within the transmission time interval (TTI), into one subframe.

Specifically, the mapper receives the data in the TTI and maps the received data to the uplink portion or uplink subframe of the special subframe for transmission. Mapping may include symbol formation, for example, in the case of LTE SC-FDMA. The data is received by the mapper in device 700B. For example, user data may be received from the medium access control (MAC) layer. Control data may be generated within or between MACs (Layer 2) and physical layers (Layer 1). For example, the acknowledgment may be generated by the HARQ entity, while the channel state feedback may be generated in response to the physical layer measurement of the channel.

The length of the second TTI (short TTI) for mapping to the uplink portion of the special subframe may be shorter than the first TTI (legacy TTI) for mapping to the uplink subframe. Alternatively, the first number of TTIs mapped to the uplink subframe is greater than the second number of TTIs to map to the uplink portion of the special subframe. Here, the lengths of the TTIs may be equal for mapping to special subframes and mapping to uplink subframes. For example, a conventional TTI length, or in other words a preconfigured length of TTI that is shorter than the length of a single subframe, may be used. However, it should be noted that in general, the invention is not limited to the same TTI length. Simply, the length and / or number of TTIs should be chosen so that the parts of the special frame and the uplink or downlink frames match their duration.

The device 700B further includes a transmitter 740 that transmits mapped data within the uplink portion of each uplink subframe and special subframe.

Correspondingly, the device 700A that receives the data in the frame having the subframe of the wireless communication system may be a part of the base station.

The apparatus 700A includes a transmission unit 710 that transmits a control signal including a special subframe setting that specifies the length of the uplink portion and / or the downlink portion of the special subframe. Accordingly, base stations that have information about cell resources and quality and also perform scheduling can set special subframe settings that should be used to communicate with the UE.

Moreover, the apparatus 700A further includes a receiver 750 that receives data mapped to the special subframe according to the special subframe setting. These are the uplink data transmitted by each UE in the cell.

The mapper 760 then demaps the data (control data including user data and / or feedback information) in the transmission time interval TTI from one subframe. The length of the second TTI for mapping to the uplink portion of the special subframe is shorter than the length of the first TTI for mapping to the uplink subframe. Alternatively, the first number of TTIs mapped to the uplink subframe is greater than the second number of TTIs to map to the uplink portion of the special subframe.

Note that device 700A may include controller 765, which controls the transmitter 710 to transmit the appropriate settings and the mapper 760 to demap the received data accordingly.

The above description focuses on the configuration and transmission of the uplink. However, the present invention is not limited thereto. Specifically, the receiver of device 700B (which may be part of the UE) can also be configured to receive data on the downlink, including the downlink portion of the special subframe. For example, based on the special subframe settings received from the base station, the device 700B receives the specified TTI in the downlink portion of the special subframe or the downlink data in the plurality of TTIs. The downlink data includes user data (PDSCH) and / or control data such as scheduling information, for example, L1 / L2 control signals that carry downlink control information (DCI) carried by PDCCH / EPDCCH in LTE. It may be.

As shown in FIG. 7, the transmitter 710 of the apparatus 700A not only outputs the special frame and / or the uplink / downlink frame configuration (broken line), but also the data mapped according to the configuration (dashed line). It can be supplied to the receiving unit 720 of 700B. On the other hand, the transmission unit 740 of the device 700B supplies uplink data (user data or control data) to the reception unit 750 of the device 700A.

Correspondingly, the device 700A, which may be mounted in the base station, has a transmitter 710 that transmits data to one or more UEs in the downlink portion of the special subframe set by the special subframe setting. ..

FIG. 8 (part of which is FIG. 8A, 8B, and 8C) shows an example of an expanded table of configurations for special subframes.

Correspondingly, the special subframe setting takes a value in the value set (0-65), and some settings in the set are for the downlink part, the uplink part length, and the TTI length. different.

In particular, the first nine settings of FIG. 8 correspond to the settings described with reference to FIG. Settings 10-65 allow the accommodation of multiple short TTIs for downlink and / or uplink. To achieve this, the length of the downlink and / or uplink portion of the special subframe is modified to provide more choice. In some cases, the guard period between the uplink parts is shortened to provide more space (symbols) for the uplink and downlink short TTIs. In detail, this can be seen in FIG. 8, where configurations with longer uplink portions of special subframes are usually provided for both cyclic and extended cyclic prefixes.

This table provides special subframe settings numbered from 0 to 65. Settings 21-65 provide a longer uplink portion of the special subframe, i.e., an uplink portion of the length of the SC-FDMA symbol between 3 and 11. Various lengths of the downlink portion are possible, resulting in various lengths of the guard period (special subframes are assumed to have 14 symbols and at least one symbol for the guard period).

FIG. 8 is merely an example. Possible settings of different numbers or orders may be provided. For example, to limit the number of bits required for signaling, the number of special subframe settings is limited to 16 (4 bits), 32 (5 bits), 64 (6 bits), or 128 (7 bits). May be good. Moreover, there may be settings that result in a guard period of less than one symbol or even zero in length. FIG. 8 should not be understood as tying a special subframe configuration index to a particular configuration. For example, it does not matter whether the setting number 19 represents 7 symbols in DwPTS and 2 symbols in UpPTS, or 6 symbols in DwPTS and 3 symbols in UpPTS. Similarly, FIG. 8 shows that the particular combination of symbols in DwPTS / UpPTS for normal cyclic prefixes must be as given in FIG. 8 for extended cyclic prefixes. Should not be understood to mean. For example, FIG. 8 lists configuration number 19 as supporting seven symbols in DwPTS and two symbols in UpPTS for normal cyclic prefixes on both uplinks and downlinks. However, in contrast to FIG. 8, for both uplink and downlink, for extended cyclic prefixes, configuration number 19 can support 6 symbols for DwPTS and 2 symbols for UpPTS (ie,). In that case, the quantity notation shown for the setting number 18).

The table shown in FIG. 8 offers the advantage of supporting the first 10 configurations currently specified for LTE legacy systems (up to Release 13). Additional settings are new and may be supported from release 14.

FIG. 8 shows many settings for both normal cyclic prefixes and extended cyclic prefixes in downlinks and uplinks. However, the present invention is not limited thereto. The number of settings may be reduced. For example, it may be beneficial not to support extended cyclic prefixes on the uplink and / or downlink to support reduced latency.

The cyclic prefix (CP) is the part that precedes each symbol in LTE (in the downlink OFDM symbol, in the uplink SC-FDMA symbol). In LTE, the length of the cyclic prefix is about 5 microseconds. The purpose of the cyclic prefix is to separate the symbols so that they can compensate for the frequency shifts that occur, for example due to high mobility. In addition to normal CP, LTE also defines extended CP with a duration of about 17 microseconds. This is to ensure that delay spreads should be included within the CP, even in large suburban and rural cells.

The number of settings may be further reduced, as not all settings are necessarily attractive for a particular uplink and / or downlink TTI length and cell size. That is, all possible settings for the uplink and downlink lengths should not be listed in the table and are therefore not available for configuration. For example, a rigorous inspection of FIG. 8 represents a setting in which configuration numbers 55, 59, 62, 64, 65 are only available if the cyclic prefix is "normal" in the downlink and uplink, and thus is potentially. Indicates that the applicability is limited. Therefore, if at least two of these settings are not available, up to 64 settings that can be efficiently represented by 6 bits are available.

As an addition or alternative, the value of the special subframe setting (index in column 1 of the table in FIG. 8) may be unique only for a particular TTI length. For example, setting # 10 (having an index 16) sets the number 2 of DwPTS symbols (OFDM symbols) and the number of UpPTS (SC-FDMA) symbols 2 in the downlink portion and the uplink portion when the TTI length is 0.2 ms. As can be shown, for a TTI length of 0.5 ms, the number of DwPTS symbols is 5 and 5. As such, the interpretation of the setting can take the TTI length as a parameter, and the TTI length is set by a setting signal that is not tied to a special subframe setting.

Alternatively, the special subframe setting may mean at least the TTI length for the uplink portion and / or the downlink portion. For example, a special subframe setting indicating the number n1 of DwPTS symbols means that the corresponding downlink TTI has a symbol length of at most n1. Similarly, a special subframe setting indicating the number n2 of UpPTS symbols means that the corresponding uplink TTI has a symbol length of at most n2.

In general, the special subframe setting advantageously indicates at least the length of the uplink portion of the special subframe where the first value is not sufficient to accommodate the data in the second TTI, the second. Values in a set of values (eg, shown in the first column of the table in FIG. 8), where the values are long enough to contain the data in the second TTI rather than the data in the first TTI. Index) is taken.

In other words, the special subframe setting is not enough to accommodate at least one legacy configuration, including the length of the uplink portion that is too short to accommodate even a short TTI, and (the TTI for a regular uplink subframe). Includes at least one new setting with sufficient uplink length to accommodate the short TTI (although not). This may be the case, for example, when the length of the short TTI is half that of the legacy TTI. In such a case, configurations 0-9 of FIG. 8 provide the length of the uplink portion of only up to 2 symbols and therefore cannot accommodate such a short TTI. However, configurations 38-65 can accommodate such short TTIs.

Mapper 730 has the advantage of
-Mapping the physical layer signal, including the sounding reference signal, to the uplink portion if the special subframe setting takes the first value,
-If the special subframe setting takes a second value, mapping control data and / or channel state information, including positive or negative acknowledgments to the downlink data, to the uplink portion, or-the special subframe setting When taking the second value, the user data is mapped to the uplink part.

In other words, if the uplink portion of the special subframe setting is not long enough to accommodate any (or configured) TTI, such an uplink portion will provide a pilot signal, such as a sounding reference signal. May be used for. As an alternative or addition, such uplink parts are used for (initial) random access, i.e. to send some other physical layer signals such as preambles used for collision avoidance. May be done. On the other hand, if the uplink portion of the special subframe setting is long enough to accommodate the TTI, the uplink portion may be used to transmit user data and / or control signals.

As already mentioned above, each special subframe may consist of multiple symbols. The special subframe setting indicates the number of symbols for the downlink part and / or the uplink part, and the special subframe further provides a guard period for one or more symbols that separates the downlink part and the uplink part. May be good.

However, special subframe settings can generally be defined only by the length of the downlink portion, or only by the length of the uplink portion, if the guard period and the length of the special subframe are fixed. Please note that it is good. Any alternative is possible as long as the special subframe setting can indicate the assignment of a particular symbol for a particular purpose (uplink, downlink, guard period).

FIG. 9 shows the detailed structure of the special subframe already shown in FIG. Specifically, the special subframe may include a guard period (GP) that begins with Nd downlink symbols (DwPTS) and separates these downlink symbols from the subsequent Nu uplink symbols (UpPTS). .. In TDD LTE, special subframes have a length of 30720 sample periods Ts equal to 1 ms.

FIG. 10 shows some exemplary mapping of TTI to special subframes. For example, in the upper example of FIG. 10, the length of the TTI differs between the uplink portion of the special subframe and the downlink portion of the special subframe. At the same time, the number of TTIs differs between the uplink portion of the special subframe and the downlink portion of the special subframe. Specifically, in this example, two short downlink TTIs are mapped to the downlink portion of the special subframe. Moreover, three short uplink TTIs are mapped to the uplink portion of the special subframe. The length of the uplink TTI is longer than the length of the downlink TTI. At the same time, the number of downlink TTIs is less than the number of uplink TTIs.

The example below FIG. 10 shows another configuration in which the number of downlink TTIs is greater than the number of uplink TTIs. At the same time, the length of the downlink TTI is shorter than the length of the uplink TTI. The guard period in this example is also shorter than the guard period in the upper example of FIG. Due to the smaller timing advance requirements, shorter guard periods may be acceptable, especially for small cells.

The length of the TTI determines the amount of data that can be transmitted within the TTI. The number of TTIs determines how often data can be collected for mapping to the resource grid. Therefore, both the length of TTI and the number of TTI affect the waiting time. As mentioned above, the invention is not limited to these examples. For example, there may be a single TTI that maps to the downlink portion of the special subframe and a single TTI that maps to the uplink portion of the special subframe. Such uplink and downlink TTIs may be TTIs of the same length or different lengths, depending on the special subframe setting, i.e., the number of symbols per portion. Alternatively, preset short TTIs of the same length may be applied to both the uplink and downlink, and the number of such short TTIs will be different for the uplink and downlink portions.

In addition, shorter TTIs may be applied to uplink subframes, downlink subframes, or both, as shown in FIG. In particular, FIG. 11 shows that one 1 ms subframe accommodates 14, 7, 4, or 2 TTIs (assuming normal CP for uplink and downlink symbols and losing generality). No) Four examples are shown. Example (a) shows a subframe to which the data in 14 TTIs is mapped. Each TTI has a length of one symbol (OFDM symbol in the case of downlink, SC-FDMA symbol in the case of uplink). Therefore, TTI corresponds to the duration of one symbol. The main advantage of a very short TTI, such as one symbol, is the ability to process the data very quickly, for example, the decryption procedure can be initiated immediately after the symbol is received. In contrast, a 1 ms TTI means that the entire subframe (= 1 ms) needs to be received before the decoding procedure can be initiated. Therefore, in the case of a short TTI, the data as well as the corresponding ACK / NACK feedback are available much faster at the receiver. ACK / NACK can be transmitted and returned to what was transmitted much faster than in the case of a 1 ms TTI.

Example (b) shows one subframe to which seven short TTIs, each with a duration of 2 symbols, are mapped. Example (c) shows one subframe to which four TTIs are mapped. These TTIs differ in their size. Specifically, two TTIs with a length of 3 symbols and 2 TTIs with a length of 4 symbols are alternately mapped (TTI (3 symbols), TTI (4 symbols), TTI (3 symbols), TTI (4 symbols)). Finally, example (d) shows two TTIs per subframe, each of which has a length of 7 symbols. The length of these TTIs loses some of the gains mentioned in the case of the one-symbol TTI, but has the advantage that these TTIs can support larger transport blocks. High forward error correction schemes such as turbo coding or low density parity check coding are specifically considered, and the coding gain increases with the length of the coded transport block. Another advantage is that a TTI with multiple symbols can transfer more energy, as the transmit power per transmit symbol is usually limited. Therefore, as far as the total energy per transport block or TTI is concerned, higher SINR can be obtained compared to a single symbol. This is particularly advantageous for uplink transmission, where the transmit power is usually limited more than the transmit power for the downlink due to the hardware cost for the power amplifiers employed in the eNBs and UEs.

As mentioned above, in LTE, the uplink portion of the special subframe is currently not available for transmitting control or user data. Since it is very short (1-2 symbols), the uplink portion is only used to send a sound reference signal for random access (initial access) and / or some uplink signals such as preambles. .. Random access is used by the UE to gain channel access. Random access is unplanned access where conflicts can occur. Pseudo-random sequences with good cross-correlation and good autocorrelation characteristics are used to allow the UEs to be distinguished in random access. Specifically, the UE randomly selects a sequence (preamble) and sends it to the base station together with its identifier to acquire resources for transmission.

According to an example of the present disclosure, the uplink portion of a special subframe is a data portion to which user data and / or control data is mapped within one or more TTIs, and a sounding reference signal and / or random access channel preamble. It is composed of a signal part that carries. For example, the uplink portion of a special subframe may form one or more TTIs, plus a predetermined number of symbols (eg, 1 or 2) that form a signal portion for transmitting a reference signal and / or an initial access preamble. Can be accommodated. Advantageously, the symbol of the signal part is the last symbol of the uplink part. In particular, this configuration conforms to the current LTE system configuration. Compliance with the LTE system allows different standard versions of the UE to use the sounding reference signal and avoids interference with PUSCH transmission.

According to the embodiment, a new special subframe is introduced in the radio frame away from the legacy switching subframes 1 and 6 shown in FIG. Such new special subframes may be available to UEs from LTE Release 13 where shorter TTIs can be configured.

Such new special subframes are advantageously set within subframes that can be configured as Multimedia Broadcast Single Frequency Network (MBSFN) subframes in LTE.

One of MBSFN's goals is to support multimedia (eg, TV) multicast or broadcast over LTE.

Specifically, according to TS36.211, v12.8.0, Section 6.1 of "Physical channel and modulation" incorporated herein by reference, down in a radio frame on a carrier that supports PDSCH transmission. A subset of link subframes can be configured as MBSFN subframes by higher layers. Each MBSFN subframe is divided into a non-MBSFN region and an MBSFN region. The non-MBSFN region spans the first one or two OFDM symbols in the MBSFN subframe. The length of the non-MBSFN region is given by the table corresponding to Table 6.7-1 from TS36.211 described above. Transmissions within the non-MBSFN region should use the same cyclic prefix length used for subframe 0. The MBSFN region within the MBSFN subframe is defined as an OFDM symbol that is not used in the non-MBSFN region.

In the MBSFN subframe, the cell-specific reference signal is transmitted only within the non-MBSFN region of the MBSFN subframe. The MBSFN subframe configuration is performed via the RRC protocol. Specifically, the configuration is transmitted from the eNodeB (base station) to the terminal within the system information block (SIB) number 2. Within the RRC, the MBSFN configuration is incorporated into the information element mbsfn-SubframeConfigList, which also defines the subframes reserved for the MBSFN in the downlink.

MBSFN subframe configurability is a special subframe that offers the benefits of reduced interference and backward compatibility. Specifically, as mentioned above, the MBSFN subframe transmits control and reference signals only within the first two OFDM symbols. Accordingly, the rest of the MBSFN may be used to map the uplink signal onto it without the risk of the legacy UE misinterpreting the uplink signal as a reference or PDCCH signal. As also shown in FIG. 8, a special subframe with only a few downlink OFDM symbols reserved for downlink and a small guard period (suitable for small cells with small time advance). Then, up to 11 SC-FDMA symbols may be available for uplink. Such a configuration is also possible with MBSFN subframes. They may be used to convey HARQ feedback and / or PUSCH sTTI, ie uplink user data, thus providing the advantage of reducing latency, especially in the case of heavy downlinks.

In other words, in this embodiment, the control signal further includes an uplink / downlink configuration that specifies, for each subframe of the frame, whether it is a downlink, an uplink, or a special subframe. .. The uplink / downlink configuration includes a first set of subframes that are configurable for multicast or broadcast and a second set of subframes that are not configurable for multicast or broadcast.

FIG. 12 (parts 12a-12h) shows an example of an uplink / downlink configuration including an additional special subframe marked with an "A" in the figure. In particular, configurations with indexes 0, 1, 2, 3, 4, 5, and 6 correspond to the respective configurations in the table of FIG. 5 and therefore do not include additional special subframes. New based on these seven conventional configurations by replacing one or more subframes configurable for MBSFN (ie, subframe numbers 3, 4, 7, 8, 9) with additional special subframes. The configuration has been added.

Another advantage of using MBSFN subframes for those subframes is that some HARQ timing relationships between the downlink and the uplink have already been defined. This is currently established in Table 10.13.1-1 of TS36.213, v12.8.0 and can be configured for subframes 3, 4, 7, 8 and 9 (ie, MBSFN). In the case of subframes), at least one UL / DL configuration is available that defines the HARQ timing relationship between the downlink data and the corresponding uplink ACK / NACK. Therefore, those established timing relationships can be reused without further effort. Moreover, subframe number 6 can be a useful candidate as it is already a special subframe in some configurations.

The additional special subframe (A) advantageously takes into account the length of the (short) TTI that can be set for the uplink. This makes it possible to transmit control data and user data in the uplink portion of the special subframe, as described above. Specifically, sPUCCH transmission and sPUSCH transmission are possible. In "sPUCCH" and "sPUSCH", a short version of each of the physical uplink control channels on the physical uplink shared channel is described. Short versions of physical uplink channels differ from PUCCH and PUSCH currently in use due to support for short TTIs (sTTIs) or multiple possible configurable sTTIs.

The special subframe setting is advantageously configurable for the first and second sets of uplink / downlink subframes, i.e. for MBSFN and the remaining subframes 1, 6 (S). This is different for subframes 3, 4, 7, 8, and 9 (A). However, since subframe # 6 may be used as both a legacy downlink subframe and a special subframe, both or either of the special subframe settings may be configurable for the subframe.

In other words, it is advantageous to have two independent special subframe settings or configuration sets applicable to the legacy special subframe (S) and the additional special subframe (A) to facilitate coexistence with the legacy UE. Can be.

Note that FIG. 12 shows many different uplink / downlink configurations. However, the present invention is not limited to providing all of these combinations as configurable. Rather, the set of configurable uplink / downlink configurations may be limited to the subset of tables shown in FIG. The choice of set size is the flexibility of the settings (provided by the large choice, that is, all possible configurations contained in the set) and the amount of memory required to store and signal each selected setting. It is a trade-off with the transmission capacity.

In summary, according to one embodiment, the wireless communication system is Long Term Evolution (LTE) and the first set of subframes is a subframe that can be configured as a Multicast Broadcast Single Frequency Network (MBSFN) subframe. A subframe within, or a second set of subframes, is a subframe having the numbers 1 and / or 6.

The examples described above show and describe various settings for special subframes. In wireless communication systems, there are usually several different channels that map to the available resources. These channels can carry different types of signals (control or user data) with different requirements for reliability and latency. Therefore, it may be advantageous to employ different special subframe settings for different channels. Specifically, the shared channel (PDSCH) may employ a different TTI length or number of TTIs than the control channel (PUSCH). For example, an uplink sharing channel may occupy more symbols than an uplink control channel. This should be set for the uplink shared channel (which can carry user data) with a larger TTI and / or more TTI in the uplink portion of the special subframe than for the uplink control channel. May be realized by.

It should be noted that the above description illustrates the present invention on the basis of the LTE system. However, the present invention is not limited thereto. Any wireless communication system that employs a special subframe used to accommodate both the uplink and downlink portions can embody the invention. Moreover, the above example mainly refers to communication between the base station and the terminal. However, in general, the above method may be used for communication between two nodes (device-to-device communication) such as two user devices. In such cases, the terms "uplink" and "downlink" should simply refer to the first and second directions of transmission (ie, UE1 to UE2 and UE2 to UE1, respectively).

Currently, uplink / downlink configurations and special subframe settings are transmitted from the base station to the UE via the RRC protocol in the system information. However, it may be beneficial to be able to dynamically reset the position and length of the sTTI length and / or short TTI special subframe.

According to the embodiment, therefore, the control signal carrying the special subframe setting is transmitted in the downlink control information as Layer 1 / Layer 2 signaling.

Such dynamic configuration is similar to that of eIMTA (enhanced Interference Mitigation and Traffic Adaption), which is a mechanism for resetting the TDD uplink / downlink configuration depending on the load and interference within and between cells. It may be executed by the method. Specifically, the eIMTA reconfiguration is performed using Layer 1 signaling, i.e. by adopting format 1C downlink control information (DCI). Format 1C is used in LTE for very compact transmission of PDSCH allocation, PDSCH transmission is constrained to QPSK for paging messages, broadcast information messages, etc. in which uplink / downlink configurations can be transmitted. NS.

Therefore, DCI format 1C is advantageously used to reconfigure the uplink / downlink configuration and special subframe settings for the purposes of the short latency described in the embodiments and examples above. You may.

Special RNTI (special RNTI) may be used to reconfigure short latency to ensure backward compatibility and maintain system design. This means that DCIs with short latency resets will only be detected by UEs with special RNTIs. The special RNTI is different from the rest of the RNTI employed for the UE or a group of UEs.

Moreover, in an advantageous way, the special subframe settings and uplink / downlink configurations have a first field that specifies which subframes are special subframes, and which symbols are up in the case of special subframes. It is carried within a second field that belongs to the link and specifies which symbol belongs to the downlink.

For example, a DCI that carries a short latency reconfiguration is used for this purpose, which subframe is used for the short TTI special subframe (ie, the short TTI, ie the uplink subframe and the downlink subframe). It may include a first field that specifies whether it is a special subframe that supports a TTI shorter than the TTI. The first field may have a length of 6 bits or less per radio frame, depending on the number of settings provided in the set of selectable configuration settings (such as the table in FIG. 5 or FIG. 12). .. Assuming that the subframe pattern defined by the first field represents one subframe per bit and the pattern repeats every 10 mims, the first field must not need to exceed 10 bits. The advantage of such a 10-bit field can be used only to indicate whether a special subframe is set as a short TTI special subframe, but a regular downlink subframe or uplink subframe. Can even indicate whether or not is set as a subframe of the short TTI. However, when only the subframes configurable for MBSFN plus subframes # 1 and # 6 are potential short TTI special subframes, then only seven subframes are such candidates. Therefore, a 7-bit first field size for a 10 ms pattern is needed. In fact, only subframes that can be set as MBSFN plus subframes # 6 of wireless frames (ie, subframes # 3, # 4, # 6, # 7, # 8, # 9 only) are set as additional special subframes. When adopting a possible embodiment, and if only additional special subframes are available for short TTI transmission, the first field containing 6 bits repeats every 10 ms, which is consistent with the MBSFN pattern that repeats every 10 ms. It should be enough to define a 10ms pattern. Alternative additional special subframe patterns may be similarly defined if the MBSFN configuration repeats every 40 ms. In this case, the 24-bit long first field should be sufficient to represent each additional special subframe candidate within the 40ms period. The size of the first field is further increased to 5 bits in a 10 ms pattern (or 20 bits in a 40 ms pattern) if only subframes that can be set as MBSFN in the radio frame can be set as special subframes in the short TTI. It may be reduced.

The DCI that carries the reset of the short latency may further include a special subframe setting, i.e., a second field that specifies the number of symbols for the uplink portion and the number of symbols for the downlink portion. The second field may have a length of 6 bits or less. 7 bits should be sufficient to provide sufficient flexibility (see table in FIGS. 6 and 8).

FIG. 13 shows a flow chart of the method according to the embodiment.

Method 1300B may be executed in a terminal (user device). Method 1300B is designed to transmit data within a frame having subframes of a wireless communication system. Each subframe is either an uplink subframe containing an uplink signal, a downlink subframe containing a downlink signal, or a special subframe containing a downlink signal portion and an uplink signal portion. The method comprises receiving a control signal including a special subframe setting that specifies the length of the uplink and / or downlink portions of the special subframe. As mentioned above, the reception of settings may be performed semi-statically and / or dynamically. For example, the configuration is first received via cell broadcast via RRC system information. The (re) setting 1310 may then be dynamically performed by DCI, for example, on PDCCH in LTE. However, the present disclosure is not limited to dynamic signaling. The (re) configuration may be transmitted (semi-statically) via the RRC protocol as an alternative or addition. The settings are separate from the special subframe settings. Upon receiving the configuration, the UE, which may include an uplink / downlink configuration as exemplified above, applies the configuration to its further transmission and reception.

In particular, method 1300B further comprises step 1320 mapping control data, including user data and / or feedback information within a transmission time interval (TTI), into one subframe. Moreover, the length of the second TTI for mapping to the uplink portion of the special subframe is shorter than the first TTI for mapping to the uplink subframe, or is mapped to the uplink subframe. The first number of TTIs is greater than the second number of TTIs for mapping to the uplink portion of the special subframe. In other words, the received configuration determines the symbols that can be used for the uplink, and according to the TTI length to be applied, the user data and / or control data to be transmitted on the uplink is mapped to the resource grid. The mapped data in the radio frame is then transmitted in step 1330 via the radio interface channel 1300.

Note that the settings received in step 1310 may be applied to data reception at the terminal. Specifically, the UE can perform step 1395 to receive a radio frame through which downlink data including downlink user data and downlink control data (eg, PDSCH and PDCCH in LTE) is transmitted. Data is demapped from the frames received in step 1390 according to the received settings for uplink / downlink subframes and / or special subframes and / or TTI length / number.

Another method 1300A is provided to receive data in a frame having subframes of a wireless communication system, each subframe containing an uplink subframe containing an uplink signal and a downlink containing the downlink signal. It is either a subframe or a special subframe that includes a downlink signal portion as well as an uplink signal portion. Method 1300A may be performed at a base station (eNB in LTE). Includes step 1370 of transmitting a control signal that includes a special subframe setting that specifies the length of the uplink and / or downlink portion of the special subframe. The settings sent are, for example, based on settings received from another network entity, based on traffic within the cell, based on the services to be carried within the cell, or based on the user profile. Then, it is selected in advance by the base station at 1360. Specifically, it is useful to consider the time advance offset required for uplink transmission by the UE, as well as the shortest possible guard period that can support quality of service (QoS) requirements for service latency.

Method 1300A further comprises step 1340 of receiving data mapped to a special subframe according to the special subframe setting. In other words, the base station receives an uplink radio frame containing data from the terminal mapped and transmitted as described above with reference to method 1300B, steps 131-10330.

After receiving frame 1340, step 1350 is performed to demap control data including user data and / or feedback information within the transmission time interval (TTI) from one subframe. The length of the second TTI for mapping to the uplink portion of the special subframe is shorter than the first TTI for mapping to the uplink subframe, or the first TTI to be mapped to the uplink subframe. The number of 1s is greater than the second number of TTIs for mapping to the uplink portion of the special subframe. Note that the demapping step 1350 is selected by the base station in step 1360, transmitted to the UE in step 1370, and applies the settings applied by the UE in step 1320.

Moreover, the base station can also apply the selected settings to the transmission of data. In particular, the method may further include step 1380, which maps the data to be transmitted to the UE based on the selected settings also transmitted to the UE in step 1370. After the mapping step 1380, a frame with the mapped data is transmitted to the UE in step 1385.

According to another embodiment, a computer program product comprising a computer-readable medium having the computer-readable program code embodied therein is provided, and the program code is adapted to carry out the present invention.

Other exemplary embodiments relate to the implementation of the various embodiments described above using hardware and software. In this regard, user terminals (mobile terminals) and eNodeBs (base stations) are provided. User terminals and base stations are adapted to perform the methods described herein and include corresponding entities that appropriately participate in methods such as receivers, transmitters, processors, and the like.

It is further recognized that various embodiments may be implemented or implemented using computing devices (processors). The computing device or processor may be, for example, a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device. Various embodiments may be implemented or embodied by a combination of these devices.

In addition, various embodiments may be implemented by a processor or by a software module that runs directly in hardware. It may also be possible to combine software modules and hardware implementations. The software module may be stored in any kind of computer-readable storage medium, such as RAM, EPROM, EEPROM, flash memory, registers, hard disk, CD-ROM, DVD, and the like.

It should be further noted that the individual characteristics of the various embodiments, individually or in any combination, are the subject of another embodiment.

Those skilled in the art will appreciate that many modifications and / or modifications to the present disclosure may be made, as set forth in the particular embodiment. Therefore, this embodiment should be considered exemplary in all respects and not limiting.

In summary, the present disclosure relates to receiving and transmitting data within a frame having subframes of a wireless communication system, where each subframe contains an uplink subframe containing an uplink signal and a down containing a downlink signal. It is either a link subframe or a special subframe that includes a downlink signal portion and an uplink signal portion. The control signal includes a special subframe setting that specifies the length of the uplink and / or downlink portion of the special subframe. Then, mapping the control data including user data and / or feedback information within the transmission time interval (TTI) to one subframe and then demapping is performed and mapped to the uplink part of the special subframe. The length of the second TTI to map is shorter than the first TTI to map to the uplink subframe, or the first number of TTIs mapped to the uplink subframe is the special subframe. Longer than the second number of TTIs for mapping to the uplink portion. Data is received or transmitted accordingly.

Claims (12)

A receiving unit that receives a control signal indicating a special subframe setting including the length of the uplink portion in the special subframe including the downlink portion and the uplink portion.
A transmitter that transmits user data within the transmission time interval (TTI) based on the control signal.
Equipped with
The second TTI in the uplink portion of the special subframe is shorter than the first TTI in the uplink subframe.
The special subframe setting is
A first value indicating the length of the uplink portion that cannot accommodate the user data in the second TTI, and
A second value indicating the length of the uplink portion that can accommodate the user data in the second TTI, and
Take one of the values,
Device. When the special subframe setting takes the first value, the sounding reference signal is transmitted and mapped at the uplink portion.
When the special subframe setting takes the second value, the user data is transmitted in the uplink portion.
The device according to claim 1. The special subframe is composed of a plurality of symbols, and the special subframe setting indicates the number of symbols of the downlink portion and the uplink portion.
The special subframe further comprises a guard period that separates the downlink portion from the uplink portion.
The device according to claim 1 or 2. The special subframe setting takes one of a plurality of values, the plurality of values being at least the length of the downlink portion, the length of the uplink portion, and the second TTI. Different about one,
The device according to any one of claims 1 to 3. The control signal further includes an uplink / downlink configuration indicating whether the control signal is a downlink subframe, an uplink subframe, or a special subframe for each subframe of one frame.
The uplink / downlink configuration includes a first set of subframes that are configurable for multicast or broadcast and a second set of subframes that are not configurable for multicast or broadcast.
The device according to any one of claims 1 to 4. The special subframe setting differs between the case of the first set of subframes having the uplink / downlink configuration and the case of the second set.
The device according to claim 5. The first set of subframes is a subframe within a subframe that can be configured as a Multicast Broadcast Single Frequency Network (MBSFN) subframe, or
The second set of subframes is a subframe having number 1 and / or number 6.
The device according to claim 5 or 6. The second TTI is different from the TTI in the downlink portion of the special subframe.
The device according to any one of claims 1 to 7. The control signal is transmitted as Layer 1 / Layer 2 signaling.
The device according to any one of claims 1 to 8. The uplink portion of the special subframe comprises a data portion to which the user data is mapped and a signal portion to which a sounding reference signal and / or a random access channel preamble is mapped.
The device according to any one of claims 1 to 9. A step of receiving a control signal indicating a special subframe setting including the length of the uplink portion in the special subframe including the downlink portion and the uplink portion, and
A step of transmitting user data within a transmission time interval (TTI) based on the control signal, and
Equipped with
The second TTI in the uplink portion of the special subframe is shorter than the first TTI in the uplink subframe.
The special subframe setting is
A first value indicating the length of the uplink portion that cannot accommodate the user data in the second TTI, and
A second value indicating the length of the uplink portion that can accommodate the user data in the second TTI, and
Take one of the values,
Method. A process of receiving a control signal indicating a special subframe setting including the length of the uplink portion in the special subframe including the downlink portion and the uplink portion, and
The process of transmitting user data within the transmission time interval (TTI) based on the control signal, and
Control and
The second TTI in the uplink portion of the special subframe is shorter than the first TTI in the uplink subframe.
The special subframe setting is
A first value indicating the length of the uplink portion that cannot accommodate the user data in the second TTI, and
A second value indicating the length of the uplink portion that can accommodate the user data in the second TTI, and
Take one of the values,
Integrated circuit.

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