WO2015042889A1

WO2015042889A1 - Method and device for reserving switchover time in device to device communication

Info

Publication number: WO2015042889A1
Application number: PCT/CN2013/084506
Authority: WO
Inventors: 李栋; 徐艳丽
Original assignee: 上海贝尔股份有限公司
Priority date: 2013-09-27
Filing date: 2013-09-27
Publication date: 2015-04-02
Also published as: CN105519226B; CN105519226A

Abstract

Embodiments of the present invention provide a method for reserving switchover time in device to device (D2D) communication. The method comprises: performing discrete Fourier transform (DFT) pre-coding on a constellational symbol of user data and mapping a symbol vector after pre-coding to some evenly spaced subcarriers so as to make other allocated subcarriers idle; transforming the symbol vector after mapping to a time domain through inverse discrete Fourier transform (IDFT) so as to enable a time domain symbol vector that is generated to show a duplicate structure; and removing at least some redundant and duplicate symbol samples from the time domain symbol vector that is provided with the duplicate structure so as to obtain some symbol structures, wherein at least some idle time obtained due to symbol removal is reserved as switchover time. The present invention also comprises an apparatus that is arranged to complete the method.

Description

Method and apparatus for reserving switching time in device-to-device (D2D) communication

Exemplary and non-limiting embodiments of the present invention relate generally to wireless communications, and more particularly to methods and apparatus for reserving handover time in device-to-device (D2D) communications.

Background technique

Driven by consumer demand, the modern communications era has brought about a huge expansion in wireless networking technology. This expansion of wireless and mobile network technology meets the needs of consumers, while providing greater flexibility and immediacy for information delivery and convenience for users.

Current and future network technologies continue to drive ease of information delivery and user convenience. In order to provide easier and faster information transfer and convenience, telecom industry service providers are improving existing networks. A growing area of development for network and communication technologies is the deployment of device-to-device (D2D) communication technologies, such as the 3rd Generation Partnership Project (3GPP), which is currently undergoing D2D-related standardization work.

Inter-device communication techniques may use the radio resources of the primary cellular system, but allow two computing devices, such as mobile terminals (also referred to as user equipment UEs), to communicate directly with one another without having to communicate their communications via components of the cellular network. This brings a lot of benefits. For example, a direct communication link between mobile terminals performing D2D communication can reduce end-to-end delay time of data exchange between terminals as compared with indirect communication via a cellular system component. Furthermore, as communication can be transferred from the cellular network to the inter-device communication link, the network load is reduced. Other benefits of D2D communication include improved coverage of the area, improved service network resources, and reduced transmission power of user equipment and network access points. Further, D2D communication can support a variety of end-user services, such as end-to-end applications, human-to-human game applications, collaborative applications, and similar applications that can be used by mobile end users that are close to each other.

In order to make D2D communication methods and communication equipment competitive, performance and cost are two factors that need to be considered in the design of D2D communication systems. In terms of cost, the design of the D2D system will Reuse existing wireless communication system technology as much as possible to reduce additional design and implementation costs. In terms of performance, for example, since D2D can use the radio resources of the primary cellular system, the performance of the D2D and its impact on the primary cellular system will have to be considered in general. Interference is one of the main factors affecting performance. In a wireless communication system supporting D2D, such as an LTE wireless communication system, interference may come from the following aspects: D2D communication uses the same resources as cellular communication, thereby causing interference between the D2D device and the cellular communication device, and different D2D devices are used. The same resources thus cause interference between D2D devices, and interference within the D2D device due to collisions between transmission and reception times due to possible timing problems in D2D communication. It should be noted that the third interference factor also causes the first two types of interference. For example, the base station can control the allocation of orthogonal time-frequency resources for D2D and cellular users, but it may still result from different timings of D2D devices and cellular users. Resource conflicts cause interference problems.

In order to solve the problem of transmission and reception collision, at the 7th Rani meeting of the 3GPP, it is agreed to reserve the guard interval when switching from the transmission state to the reception state and from the reception state to the transmission state, and further assume that the guard interval has a length of 624. Ts, where Ts=l/30.72e6 is the sampling time of the LTE system with a bandwidth of 20 MHz (see Draft-Minutes_report_RAN 1 #74- νθ 10 , which is available from http://www.3gpp.org/ftp /tsg_ranAVGl_RLl/TSGRl_74/Report/ Get). Further research is currently needed on how to effectively implement this switching time in the LTE frame structure, and 3GPP has not yet standardized this. In a proposal at the 3GPP Ranl #74 conference, a simple and straightforward solution was proposed, which punctured data symbols at the transmitting or receiving end, for example, at the sender, the beginning of the first symbol of the beacon. Hole and/or perforate the end of its last symbol (see Rl-132912, Beacon channel design for D2D, RAN 1-74, available from http:〃 www.3gpp.org/ftp/tsg-ran/ WGl-RLl/TSGR1-74/Docs/ obtained). A disadvantage of this approach is that a stiff puncturing operation will result in interference to the useful data carrier, including self-interference between the same user data carrier and mutual interference between different sub-bands used by different users. This is because the puncturing operation destroys the orthogonality of the multi-carrier signal. Summary of the invention

In view of this, one of the objects of embodiments of the present invention is to propose a handover time construction method that achieves reservation of handover time at a very low frequency efficiency and implementation complexity.

According to an aspect of the present invention, a method for reserving handover time in device-to-device (D2D) communication is provided, including:

- performing discrete Fourier transform (DFT) precoding on the constellation symbols of the user data to obtain a precoded symbol vector;

- mapping the precoded symbol vector onto a portion of the equally spaced subcarriers, leaving the other allocated subcarriers unused;

- transforming the mapped symbol vector into the time domain by inverse discrete Fourier transform (IDFT) such that the generated time domain symbol vector presents a repeating structure;

Removing at least a portion of the redundantly repeated symbol samples from the time domain symbol vector having a repeating structure to obtain a partial symbol structure, wherein the idle time obtained by at least partially removing the symbol samples is reserved for the switching time.

In an embodiment of the invention, the length of the precoded symbol vector is half of the number of allocated subcarriers; and wherein the precoded symbol vector is mapped only to even subcarriers.

According to a further embodiment of the invention, a length-expanded cyclic prefix (CP) is employed in the partial symbol structure, and the length extension is obtained using at least partially redundant repetitive symbol sampling.

According to another aspect of the present invention, a method for performing a transmission/reception state switching in device-to-device (D2D) communication is provided, including:

Determining whether to switch the transmit/receive state in the data frame;

Determining a switching symbol position in determining a data frame to be switched;

Transmitting/receiving a partial symbol structure within the determined switching symbol and performing switching of the transmission/reception state by using a switching time reserved in the partial symbol structure, wherein the partial symbol structure is one of the above-described embodiments according to the present invention Method generated.

According to an embodiment of the present invention, determining whether to switch transmission/reception in a data frame The state includes: when the data frame is different from the transmission/reception state of the previous data frame or the subsequent data frame, it is determined that the handover is required.

In another embodiment of the present invention, determining the switching symbol position includes determining the symbol position as the data when the data frame is different from a previous data frame transmission/reception state and not switching at a previous data frame end The start symbol of the frame.

In still another embodiment of the present invention, determining the switching symbol position includes determining the symbol position as the data when the data frame is different from a subsequent data frame transmission/reception state and not switching at a beginning of a subsequent data frame The symbol at the end of the frame.

In some embodiments of the present invention, determining the switching symbol position may further include determining that the symbol position is the data frame when the data frame is different from the before/after data frame transmission/reception state and the data frame is not switched before and after. The end of the symbol and the start symbol.

According to still another aspect of the present invention, an apparatus for reserving a handover time in device-to-device (D2D) communication includes:

a precoding unit configured to perform discrete Fourier transform (DFT) precoding on constellation symbols of user data to obtain a precoded symbol vector;

a mapping unit configured to map the precoded symbol vector to a portion of the equally spaced subcarriers, leaving the other allocated subcarriers unused;

a transform unit configured to transform the mapped symbol vector into a time domain by an inverse discrete Fourier transform (IDFT) such that the generated time domain symbol vector exhibits a repeated structure;

a removing unit configured to remove at least a portion of the redundantly repeated symbol samples from the time domain symbol vector having a repeating structure to obtain a partial symbol structure, wherein the idle time obtained by at least partially removing the symbol samples is obtained Reserved for switching time.

According to some embodiments of the invention, the length of the precoded symbol vector in the precoding unit is half of the number of allocated subcarriers; and wherein the precoded symbol vector is mapped only to even subcarriers.

According to a further embodiment of the invention, the removal unit may be further configured to generate a length-expanded cyclic prefix (CP) for the partial symbol structure, and the length extension is obtained using at least partially redundant repetitive symbol sampling. According to still another aspect of the present invention, an apparatus for performing a transmission/reception state switching in device-to-device (D2D) communication includes:

a first determining unit configured to determine whether to switch a transmit/receive state in the data frame;

a second determining unit configured to determine a switching symbol position in the data frame determined to be switched;

a processing unit configured to transmit/receive a partial symbol structure within the determined switching symbol and to perform switching of a transmission/reception state by using a switching time reserved in the partial symbol structure, wherein the partial symbol structure is according to the present invention The method of generating a partial symbol structure in the foregoing embodiment is generated.

In a further embodiment of the present invention, the first determining unit is further configured to determine that a handover is required when the data frame is different from a transmission/reception state of a previous data frame or a subsequent data frame.

In still another embodiment of the present invention, the second determining unit is further configured to determine the symbol when the data frame is different from the previous data frame transmission/reception state and is not switched at the end of the previous data frame. The location is the start symbol of the data frame.

According to another embodiment of the present invention, the second determining unit is further configured to determine the symbol when the data frame is different from the next data frame transmission/reception state and is not switched at the beginning of the next data frame. The position is the symbol at the end of the data frame.

In a further embodiment of the present invention, the second determining unit may be further configured to determine that the data frame is different from the previous and succeeding data frame transmission/reception states and that the symbol position is determined when the front and rear data frames are not switched. The end symbol and start symbol of the data frame. DRAWINGS

The embodiments of the present invention have been generally described, and the present invention will now be described in further detail with reference to the accompanying drawings. In the figure:

1 shows an example of a communication system for implementing device-to-device communication in accordance with some example embodiments;

2 is for use in device-to-device (D2D) communication, in accordance with an embodiment of the present invention. Schematic flow chart of a method for reserving handover time;

Figure 3) is a schematic diagram of common symbols;

Figure 3 (b) is a schematic diagram of a time domain symbol vector having a repeating structure obtained in the process of generating a partial symbol structure in accordance with an embodiment of the present invention;

- Figure 3 (cd) shows a schematic diagram of a partial symbol structure in accordance with an embodiment of the present invention; Figure 4 is a diagram of a method for performing transmission/reception state switching in device-to-device (D2D) communication, in accordance with an embodiment of the present invention. Schematic flow chart;

Figure 5 is a diagram showing the location of a switching symbol in a data frame, in accordance with some embodiments of the present invention;

Figure 6 shows a device-to-device according to some exemplary embodiments of the present invention.

(D2D) A schematic block diagram of a device that reserves switching time in communication;

7 is a schematic block diagram of an apparatus for performing a transmit/receive state switch in device-to-device (D2D) communication, according to some exemplary embodiments of the present invention;

Figure 8 is a block diagram of a user equipment;

9 is a schematic diagram showing system performance obtained in accordance with an embodiment of the present invention. detailed description

The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

FIG. 1 illustrates a block diagram of an exemplary communication system 100 for implementing device-to-device communication in accordance with some example embodiments. It is to be understood that the illustrations of the system 100 and the other figures are provided as an example of an embodiment, and should not be construed as limiting the scope and spirit of the disclosure in any way. In this regard, while Figure 1 illustrates an example of a communication system configuration for implementing device-to-device communication, many other configurations may be utilized to implement embodiments of the present invention.

In an embodiment of the invention, as shown in FIG. 1, system 100 can include an access point 102 that can provide wireless access to network 106. As an example, access point 102 can include a base station, a base transceiver station, a Node B, an evolved Node B (eNB), and/or the like. Network 106 may include one or more wireless networks, one or more wired networks, or some combination thereof, and in some embodiments, may include the Internet to A small part. In some exemplary embodiments, network 106 may use one or more mobile access mechanisms, such as Long Term Evolution (LTE), LTE-Advanced (LTE-A), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), broadband Code Division Multiple Access (W-CDMA), CDMA2000, Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), and/or similar systems. Accordingly, it will be appreciated that while certain embodiments of the invention are described in terms of LTE and/or LTE-A systems, this is only exemplary and not limiting.

In some exemplary embodiments, the wireless access point 102 can be configured to provide user equipment (UE) 104 with wireless access via the link 108 to the network 106. The UE 104 may comprise any mobile communication device such as a mobile telephone, a portable digital assistant (PDA), a smart phone, a pager, a notebook computer, a portable gaming device, or any other numerous handheld or portable communication devices, computing devices, content generating devices , content consumer devices, or a combination thereof. The wireless access point 102 can be further configured to support the establishment of D2D communication between two or more UEs 104. In this regard, the wireless access point 102 can be configured to allocate resources for D2D communication and D2D discovery, coordinate D2D link establishment, and/or perform other similar functions.

In the exemplary system shown in FIG. 1, two UEs 104 that can participate in D2D communication with each other through the D2D link 110 are shown. However, it will be understood that the two UEs 104 are shown by way of example and not limitation. In this regard, it will be appreciated that more than two UEs 104 may participate in D2D communication over one or more D2D links 110.

Since the propagation delay of D2D communication is different from the propagation delay of the device to the access point, in some cases, the access point cannot accurately control the transmission/reception timing of the D2D device, which may cause a collision between transmission and reception, and Causes interference. In order to avoid this problem, a method for providing a reserved switching time for status switching of transmission/reception is proposed according to an embodiment of the present invention.

2 is a schematic flow diagram of a method for reserving handover time in device-to-device (D2D) communication, in accordance with an embodiment of the present invention.

As shown in FIG. 2, a discrete Fourier transform (DFT) precoding is performed on the constellation symbols of the user data in step 201 to obtain a precoded symbol vector, wherein the length of the precoding is less than the number of allocated subcarriers. In step 202, the precoded symbol vector is only mapped to a portion of the equally spaced subcarriers, and the other allocated subcarriers are left unused, that is, zero is transmitted. Thereby, the mapped symbol vector is obtained, the length of which is equal to the number of allocated subcarriers, wherein the symbol samples corresponding to the unused subcarriers are padded with zeros.

At step 203, the mapped symbol vectors are transformed into the time domain by inverse discrete Fourier transform (IDFT) such that the generated time domain symbol vectors exhibit a repeating structure.

Then, at step 204, at least a portion of the redundantly repeated symbol samples are removed from the time domain symbol vector having a repeating structure to obtain a partial symbol structure, wherein the idle time obtained by at least partially removing the symbol samples is reserved. Switch time.

According to some embodiments of the invention, the DFT length employed in step 201 may be half the length of the allocated subcarriers, and in this case, in step 202, the precoded symbol vector is mapped only to even subcarriers.

According to another embodiment of the present invention, step 204 of the method may further comprise generating a length-expanded cyclic prefix (CP) for the partial symbol structure, and the length extension is sampling with one or more redundant repetition symbols acquired.

Figure 3 shows a schematic diagram of a partial symbol structure in accordance with some exemplary embodiments. 3(a) is a schematic diagram of a general symbol structure used as a reference, which includes a CP portion and a data portion, which is hereinafter referred to as symbol eight. Figure 3 (b) is a diagram showing a time domain symbol vector having a repeating structure obtained in the process of generating a partial symbol structure in accordance with an embodiment of the present invention. Figure 3 (c-d) shows a schematic diagram of a partial symbol structure in accordance with an embodiment of the present invention. Fig. 3(c-d) is obtained by further processing the symbol vector having a repeating structure in Fig. 3(b).

According to an embodiment of the present invention, the symbol vector having the repeated structure shown in FIG. 3(b) may be shifted such that a switching time is left between the end of the symbol and the start position of the next symbol, that is, as shown in FIG. The partial symbol structure shown in 3 (C) is hereinafter referred to as symbol C. In symbol C, the switching time is at the end of the symbol, the shaded portion at the left end of Figure 3(c) indicates the repeated symbol sampling that was removed, and the unrepeated repeated symbol sample can be used as the CP for length extension.

According to another embodiment of the present invention, the repeating junction shown in FIG. 3(b) can be The end of the constructed symbol vector is aligned with the start position of the next symbol, and the switching time is reserved at its starting position, which results in a partial symbol structure as shown in Fig. 3 (d), which is referred to as a symbol in the following. D. In symbol D, the switching time is at the beginning of the symbol, where the shaded portion represents the repeated symbol samples removed to meet the length requirement of the switching time. Also, the unremoved repeated symbol samples can also be used as the length extended CP in the example of FIG. 3(d).

It should be noted that although the length extended CP is employed in the example of Fig. 3, in other embodiments, the normal length CP may also be used in the partial symbol structure.

Another embodiment of the present invention provides a method of switching a transmission/reception state using the partial symbol structure. 4 is a schematic flow chart showing a method for performing transmission/reception state switching in device-to-device (D2D) communication according to an embodiment of the present invention.

As shown in FIG. 4, the D2D device 104 determines in step 401 whether the transmit/receive state will be switched in the data frame; the determination may be based, for example, on a pre-defined, based on an indication by the access point 102, or based on coordination with another device 104. result.

When it is determined that the transmission/reception state will be switched at data frame i, then at step 402, the symbol position of the reserved handover time in the data frame, i.e., the location of the handover symbol, is determined. The location may be, for example, predefined or indicated by access point 102, or determined based on inter-device coordination.

Then, in step 403, within the determined switching symbol, a specific symbol structure, that is, a partial symbol structure generated by the method according to an embodiment of the present invention, is transmitted or received, and the switching time reserved in the switching symbol is performed. Switching of the send/receive status.

According to a further embodiment of the present invention, determining whether to switch the transmission/reception state in step 401 comprises determining that handover is required when the data frame is different from the transmission/reception state of the previous data frame or the subsequent data frame.

According to a further embodiment of the present invention, the switching symbol determined when the data frame is different from the previous data frame transmission/reception state in step 402 and not switched at the end of the previous data frame may be the data frame. Start symbol.

According to another embodiment of the present invention, in step 402, when the data frame is different from the transmission/reception state of the latter data frame and is not switched at the beginning of the latter data frame, The switching symbol can be the last symbol of the data frame.

According to still another embodiment of the present invention, the switching symbol determined when the data frame is different from the previous and succeeding data frame transmission/reception states in step 402 and is not switched when the preceding and succeeding data frames are not switched may be the end symbol of the data frame and Start symbol.

Figure 5 is a diagram showing the location of a switching symbol in a data frame, in accordance with some embodiments of the present invention. In the example of Fig. 5, it is assumed that the data frame is a transmission/transmission subframe. As shown in FIG. 5, in some embodiments, the partial symbol structure may be located at the end of the sub-frame, in which case the partial symbol structure has the structure of symbol C in FIG. In other embodiments, the partial symbol structure may be the start symbol located in the sub-frame, in which case the partial symbol structure has the structure of symbol D in Figure 3. In still another embodiment, the partial symbol structure may be located at the beginning symbol and the last symbol of the subframe, in which case the start symbol has the structure of the symbol D in FIG. 3, and the end symbol has the structure as shown in FIG. The structure of the symbol C.

The following is an example of how to obtain a partial symbol structure and switching time in the LTE D2D background, taking an embodiment in which the start and end symbols of the data frame are all switching symbols. It should be understood that the described LTE background is merely an example of wireless communication, and embodiments of the present invention may be applied in other similar systems.

In this embodiment assumed that the user data in a resource block size (in LTE, a resource block includes N _s. = 12 subcarriers) in D2D discovery transmission channel, and the assumed length N _se is switched by the symbol Half of the DFT precoding, the number of user data constellation symbols that can be loaded in the data frame is:

Ncsym― (Ndsym 1) N _S c where N _esym represents the number of user data constellation symbols that can be loaded in the data frame, N _se represents the number of subcarriers, and N _dsym represents the number of symbols in the data frame.

As an example, the user data constellation symbol is represented as ^, ^, ^, ..., ⁶ ^ . The sequence of symbols is then divided into a number of symbol vectors so that DFT precoding employed in LTE uplink can be applied subsequently to reduce the average ratio (PAPR) to achieve higher amplifier efficiency and potentially lower out-of-band emissions. Thus, the constellation symbol is converted into a plurality of symbol vectors, which respectively correspond to one SC-FDMA symbol. It should be noted that in this implementation of the invention it is used for The symbol vectors of the start and end SC-FDMA symbols are obtained with a length of NJ2, and the symbol vectors corresponding to other SC-FDMA symbols include _Nse symbol elements. Each symbol vector can represent the following:

d _A d

d

ί = 1,2,···,Ν d

It represents the i-th user data constellation symbol. After that, the above symbol vectors are respectively subjected to DFT precoding to obtain a -DFT precoded vector; ^ , , · · · , x _msym _ :

= i = Q,N _d ,_i

j = l,2,-,N _dsym -2 It should be noted that ^'^ν is obtained by half-length DFT (N _sc /2-point DFT) precoding, while other vectors are pre-processed by full-length DFT (^ point DFT) Coding obtained. Then the vector of length N _sc /2 ^, the sign of ^ is placed on the even subcarrier, and the other subcarriers are set to zero, thus ^. The length of , expands to _Nse , which is the same length as other vectors.

0

These vectors are then mapped onto the assigned subcarriers, for example in this embodiment, Mapped to the subcarriers used to discover the channel. The subcarriers may be obtained automatically by the UE or scheduled by the access point. Next, as in the conventional SC-FDMA operation, the vector is converted to the time domain by an IDFT operation.

It is worth noting that for the start and end SC-FDMA symbols, because of the special mapping of their data on subcarriers (only mapped to even subcarriers), the vector exhibits a repetitive structure in the time domain, as shown in Figure 3. . This feature allows for a reserved switching time by removing some of the repeated redundant samples.

According to another embodiment of the invention, the partial repetition symbol sampling can also be used to extend the CP. Since the reserved switching time does not normally occupy all of the repeated symbols, a part can be used for the CP for some potential purpose, for example for auxiliary time and/or frequency synchronization.

Yet another embodiment of the present invention is an apparatus for reserving switching time in device-to-device (D2D) communication. Figure 6 shows a schematic block diagram of a device 600 for reserving handover time in device-to-device (D2D) communication.

As shown in FIG. 6, the apparatus 600 includes a precoding unit 601 configured to perform discrete Fourier transform (DFT) precoding on constellation symbols of user data to obtain a precoded symbol vector; mapping unit 602, configured Mapping the precoded symbol vector to a portion of the equally spaced subcarriers while leaving the other allocated subcarriers unused; the transform unit 603 is configured to map the mapped by inverse discrete Fourier transform (IDFT) The symbol vector is transformed into the time domain such that the generated time domain symbol vector presents a repeating structure; and the removing unit 604 is configured to remove at least a portion of the redundant repeat from the time domain symbol vector having the repeating structure The symbol is sampled to obtain a partial symbol structure in which the idle time obtained by at least partially removing the symbol is reserved as the switching time.

According to some embodiments, wherein the length of the precoded symbol vector obtained in the precoding unit 601 is half of the number of allocated subcarriers; and wherein the precoded symbol vector is mapped only to even subcarriers.

According to another embodiment, the removal unit 604 can be further configured to generate a length-expanded cyclic prefix (CP) in the partial symbol structure, and the length extension is obtained using at least partially redundant repetitive symbol sampling. Another embodiment of the present invention provides an apparatus for performing a transmission/reception state switching in device-to-device (D2D) communication. FIG. 7 shows a schematic block diagram of an apparatus 700 for performing a transmit/receive state switch in device-to-device (D2D) communication.

As shown in FIG. 7, the apparatus 700 includes a first determining unit 701 configured to determine whether to switch a transmission/reception state in a data frame. The second determining unit 702 is configured to determine in a data frame to be switched. Determining a switching symbol position; and processing unit 703 configured to transmit/receive a partial symbol structure within the determined switching symbol and to complete switching of the transmission/reception state by using a switching time reserved in the partial symbol structure.

According to some embodiments of the present invention, the first determining unit 701 may be further configured to determine that the data frame is different from the sending/receiving state of the previous data frame or the subsequent data frame. Switch.

According to another embodiment of the present invention, the second determining unit 702 may be further configured to: when the data frame is different from a previous data frame transmission/reception state and not performed at the end of the previous data frame The symbol position is determined to be the start symbol of the data frame upon handover.

According to still another embodiment of the present invention, the second determining unit 702 is further configured to: when the data frame is different from the next data frame transmission/reception state and not to switch at the beginning of the latter data frame The symbol position is determined to be the end symbol of the data frame.

In a further embodiment of the present invention, the second determining unit 702 may be further configured to determine that the data frame is different from the previous and succeeding data frame transmission/reception states and determine that the symbol position is when the data frames are not switched. The end symbol and start symbol of the data frame.

According to some embodiments of the invention, the above device may be a device that is included or applied to the user device 104. FIG. 8 illustrates an exemplary block diagram of an apparatus that may be included or applied to a UE 104 that may be configured to perform the functions/method steps as described in the embodiments herein. However, it should be noted that the components, devices or components illustrated in Figure 8 or described below with respect to Figure 8 may not be mandatory, and thus some may be omitted in certain embodiments. Moreover, some embodiments may include more or different components, devices or elements than those illustrated in FIG. 8 and described with respect to FIG. Referring now to FIG. 8, UE 104 may include, or otherwise be in communication with, processing system 810, which may be configured to perform operations in accordance with the exemplary embodiments disclosed herein. Processing system 810 can be configured to perform data processing, execution of applications, and/or other processing and management services in accordance with one or more exemplary embodiments. In some embodiments, the UE 104, or portions or components thereof, such as the processing system 810, can be implemented as or include a chip or chipset. Thus, in some cases, UE 104 or processing system 810 can be configured to implement one embodiment of the present invention on a single chip or as a separate "system on a chip." Thus, in some cases, a chip or chipset may constitute a means for performing one or more operations to provide the functionality described herein.

In some exemplary embodiments, processing circuit 810 can include a processor 812, and in some embodiments, can further include memory 814. Processing system 810 can communicate with one user interface 816 and/or a communication interface 818, or otherwise control them. Thus, processing system 810 can be implemented as a circuit chip (e.g., an integrated circuit chip) that is configured (e.g., by hardware, software, or a combination of hardware and software) to perform the operations described herein.

User interface 816 (if implemented) can communicate with processing system 810 to receive an indication of user input at user interface 816 and/or provide the user with some form, such as audible, visual, mechanical, or otherwise. Output.

Communication interface 818 may contain one or more interface mechanisms that enable communication with other devices and/or networks. In some cases, the communication interface 818 can be any device, such as one device or circuit included in hardware or a combination of hardware and software configured to receive data from or transmit data to a network, and/or Any other device or module that is in communication with processing system 810. As an example, communication interface 818 can support D2D communication with another UE 104, such as through a D2D link 110.

In some example embodiments, memory 814 may include one or more non-transitory memory devices such as, for example, volatile and/or non-volatile memory that may be fixed or removable. The memory 814 can be configured to store information, data, applications, instructions, etc., such that the UE 104 can perform various functions/method steps in accordance with one or more exemplary embodiments. For example, memory 814 can be configured to be cached for use by processor 812 Input data. Additionally or alternatively, memory 814 can be configured to store instructions for execution by processor 812. As yet another alternative, the memory 814 can include one or more databases that can store various files, content, or data sets.

Processor 812 can be implemented in many different ways. For example, processor 812 can be implemented as various processing devices, such as one or more microprocessors or other processing elements, a coprocessor, a controller or include, for example, an ASIC (Application Specific Integrated Circuit), an FPGA ( Various other computing or processing devices for integrated circuits such as field programmable gate arrays, or the like. In some exemplary embodiments, processor 812 can be configured to execute instructions stored on memory 814 or otherwise accessible by processor 812. Thus, whether configured by hardware or a combination of hardware and software, the processor 812 can be representative of an entity capable of performing operations in accordance with embodiments of the present invention (e.g., physically implemented on a circuit) to a processing system 810. form) . Thus, for example, when processor 812 is implemented as an ASIC, FPGA or the like, the processor 812 can be hardware that is specifically configured to perform the operations described herein. Alternatively, as another example, when processor 812 is implemented as an executor of software instructions, the instructions may specifically configure processor 812 to perform one or more of the operations described herein.

In some exemplary embodiments, processor 812 (or processing system 810) may be implemented to include, or otherwise control, a D2D manager 820. Likewise, D2D manager 820 can be implemented as a variety of devices, such as circuitry, hardware, a computer including a processing device (eg, processor 812) stored on a computer readable medium (eg, memory 814) A computer program product readable by program instructions, or some combination thereof. The D2D manager 820 may be capable of communicating with one or more memories 814 or communication interfaces 818 to access, receive, and/or transmit data. In accordance with some embodiments, determining whether to perform a transmit/receive state switch in operation of the apparatus may be based on a predefined value, such as a value/decision criterion stored in 814 in memory, or based on obtaining from access point 102 via communication interface 818. The indication is based on the coordination result obtained from the other device 104 via the communication interface 818.

In some embodiments, determining the transmit/receive state in the operation of the device will be The operation of changing and determining the symbol location at which the handover time is reserved includes obtaining the location of the handover symbol by, for example, based on a pre-defined stored in memory 814 or based on an indication obtained from access point 102 via communication interface 818, or It is based on coordination between devices via communication interface 818.

Figure 9 shows computer simulation results of D2D communication performance obtained in accordance with one embodiment of the present invention. The parameters used in the simulation are shown in Table 1. In FIG. 9, the simulation result shows that the method for obtaining the reserved switching time based on the partial symbol structure proposed by the present invention has a gain of about 0.3 to 0.4 dB compared with the direct puncturing method in the prior art, and the result depends on each The number of SC-FDMA symbols available in the discovery sub-frame.

Table 1: Simulation parameters

Benefit from the foregoing description and the revelation in the related drawings, the fields related to the present invention Many modifications and other embodiments of the inventions described herein will be apparent to those skilled in the art. Therefore, it is understood that the invention is not limited to the particular embodiments disclosed, and the scope of the appended claims. In addition, while the foregoing description and the associated drawings are described in the context of exemplary embodiments of certain combinations of elements and/or functions, it is understood that other alternative embodiments may provide different elements and/or functions. The combination of the claims is not to be construed as a limitation. In this regard, for example, it is contemplated that combinations of elements and/or functions described above may also be described in the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive manner and not for the purpose of limitation.

Claims

Claim

1. A method for reserving switching time in device-to-device (D2D) communication, comprising:

2. The method of claim 1 wherein the length of said precoded symbol vector is one half of the number of allocated subcarriers; and wherein said precoded symbol vector is mapped only to even subcarriers.

3. The method of claim 1 wherein a length extended cyclic prefix (CP) is employed in said partial symbol structure and said length extension is obtained using at least partially redundant repeated symbol samples.

4. A method for performing a transmit/receive state switch in device-to-device (D2D) communication, comprising:

Determining whether to switch the transmit/receive state in the data frame;

Transmitting/receiving a partial symbol structure within the determined switching symbol and performing switching of the transmission/reception state using a switching time reserved in the partial symbol structure, wherein the partial symbol structure is according to any of claims 1-3 The method described is generated.

5. The method of claim 4, wherein determining whether to switch the transmit/receive state in the data frame comprises: transmitting/receiving the data frame with a previous data frame or a subsequent data frame When the status is different, it is determined that a switch is required.

6. The method according to claim 4 or 5, wherein when the data frame is different from the previous data frame transmission/reception state and no handover is performed at the end of the previous data frame, determining the handover symbol position as the data frame Start symbol.

7. The method of claim 4 or 5, wherein said data frame is sent with a subsequent data frame

/ When the reception state is different and no handover is made at the beginning of the latter data frame, the handover symbol position is determined to be the end symbol of the data frame.

8. The method of claim 4 or 5, wherein when the data frame is different from the preceding and succeeding data frame transmission/reception states and the previous and subsequent data frames are not switched, determining the switching symbol position as the end symbol of the data frame and starting symbol.

9. A device for reserving switching time in device-to-device (D2D) communication, comprising:

10. Apparatus according to claim 9, wherein the length of said precoded symbol vector is one half of the number of allocated subcarriers; and wherein said precoded symbol vector is mapped only to even subcarriers.

11. Apparatus according to claim 9 wherein a length extended cyclic prefix (CP) is employed in said partial symbol structure and the length extension is obtained using at least partially redundant repetitive symbol sampling.

12. One for performing a transmit/receive state cut in device-to-device (D2D) communication Equipment exchanged, including:

a processing unit configured to transmit/receive a partial symbol structure within the determined switching symbol, and complete switching of a transmission/reception state by using a switching time reserved in the partial symbol structure, wherein the partial symbol structure is according to claim 1 - Generated by the method of any of the preceding claims.

The apparatus according to claim 12, wherein said first determining unit is further configured to determine that a handover is required when said frame is different from a transmission/reception state of a previous data frame or a subsequent data frame.

14. The apparatus according to claim 12 or 13, wherein said second determining unit is further configured to determine when the current data frame is different from a previous data frame transmission/reception state and is not switched at the end of the previous data frame The symbol position is the start symbol of the data frame.

15. Apparatus according to claim 12 or claim 13, wherein said second determining unit is further configured to: when said data frame is different from a subsequent data frame transmission/reception state and not to be switched at the beginning of a subsequent data frame The symbol position is determined to be the end symbol of the data frame.

16. The device of claim 12 or 13, wherein the second determining unit is further configured to determine when the data frame is different from a before/after data frame transmission/reception state and when the before and after data frames are not switched The symbol position is the end symbol and the start symbol of the data frame.