JP7194766B2 - Wireless communication method, wireless communication device and wireless communication system - Google Patents

Description

The present disclosure relates to the field of wireless communications, and more particularly to wireless communication methods, wireless communication devices and wireless communication systems in machine-type communications.

Machine-Type Communication (MTC) is a new type of communication in Release 12 of The 3rd Generation Partnership Project (3GPP) and is an important source of revenue for operators and operator perspectives. has great potential from Based on market and operator requirements, one of the key requirements of MTC is to improve the coverage of MTC's User Equipment (UE). Therefore, MTC is further envisioned in Release 13 to support coverage enhancement of eg 15 dB. This type of coverage enhancement technique is very useful for some MTC UEs, such as underground sensors with large loss in signal strength due to penetration loss.

Repetition is one of the key techniques for supporting MTC UEs in coverage extension. Specifically, for MTC UEs in coverage extension, each channel basically needs to perform multiple repetitions (eg, 100 times). On the receiver side, the receiver combines all repetitions of the channel to decode the information. Thus, coverage enhancement requirements are achieved through signal accumulation and power enhancement due to repetition.

One non-limiting exemplary embodiment provides a method for maximizing system performance in MTC with coverage extension.

In a first general aspect of the present disclosure, a wireless communication method is provided comprising transmitting a reference signal and a data signal in a physical resource block (PRB) at a coverage enhancement level, wherein the reference signal in the PRB is The number of resource elements to transmit is determined by the coverage enhancement level, channel type and/or coding rate of the data signal.

In a second general aspect of the present disclosure, a wireless communication method is provided comprising receiving a reference signal and a data signal in a physical resource block (PRB) transmitted at a coverage enhancement level, The number of resource elements for transmitting reference signals is determined by the coverage enhancement level, channel type, and/or coding rate of the data signal.

In a third general aspect of the present disclosure, a wireless communications apparatus is provided that includes a transmission unit configured to transmit reference signals and data signals in physical resource blocks (PRBs) at a coverage enhancement level. , PRBs are determined by the coverage enhancement level, the channel type, and/or the coding rate of the data signal.

In a fourth general aspect of the disclosure, a wireless communication apparatus includes a receiving unit configured to receive reference signals and data signals in physical resource blocks (PRBs) transmitted at a coverage enhancement level. and the number of resource elements for transmitting reference signals in a PRB is determined by the coverage enhancement level, channel type, and/or coding rate of the data signal.

Note that the general or specific embodiments may be implemented as systems, methods, integrated circuits, computer programs, storage media, or any selective combination thereof.

Further benefits and advantages of the disclosed embodiments will be apparent from the specification and drawings. Benefits and/or advantages may be obtained individually through various embodiments and features of the specification and drawings, all of which need to be provided in order to obtain one or more of such benefits and/or advantages. no.

These and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. With the understanding that these drawings show only some embodiments in accordance with the disclosure and are therefore not to be construed as limiting its scope, the present disclosure will be further illustrated through the use of the accompanying drawings. be explained in detail.

FIG. 4 is a schematic diagram illustrating an example of BLER characteristics of PUSCH repetition; 4 is a flow chart of a wireless communication method according to an embodiment of the present disclosure; 4 is a flowchart of a wireless communication method according to another embodiment of the present disclosure; FIG. 4 is a block diagram illustrating a wireless communication device in accordance with a further embodiment of the present disclosure; FIG. 4 is a block diagram illustrating a wireless communication device according to yet another embodiment of the present disclosure;

In the following detailed description, reference is made to the accompanying drawings which form a part hereof. In the drawings, similar symbols generally identify similar components, unless context dictates otherwise. It will be readily understood that aspects of the present disclosure may be arranged, permuted, combined, and designed in a wide variety of different configurations, all of which are expressly contemplated and form part of the present disclosure. doing.

<Basic knowledge that forms the principle of this disclosure>
As described in Background Art, in repetition, which is one of the important techniques for MTC coverage extension, long repetition lasts for a long time, and MTC UE maintains an active state for a long time in order to always be in a receiving state. you will be asked to do so. This consumes a lot of UE power and occupies a lot of system resources. Therefore, other coverage enhancement techniques, such as increasing reference signal (RS) density, are effective in achieving coverage enhancement to reduce the number of repetitions.

To introduce a simple RS density increase, take one Physical Resource Block (PRB) as an example. One PRB is composed of 14 symbols in the time domain and 12 subcarriers in the frequency domain, and one symbol and one subcarrier form one resource element (RE). That is, one PRB has a total of 12×14 REs. The standard specifies that in one PRB, some REs are allocated to transmit some types of reference signals and other REs are allocated to transmit data signals. For a particular reference signal in the case of normal usage, the standard specifies the number of REs allocated to transmit the reference signal in one PRB and their location. Therefore, the RS density, ie the ratio of REs to transmit reference signals to all REs in one PRB, is specified in the standard. Therefore, increasing the RS density means increasing the number of REs for transmitting reference signals in one PRB.

By increasing the RS density, the channel estimation performance and signal quality can be improved, thus reducing the number of UE repetitions for MTC with coverage extension.

One straightforward solution for increasing the RS density is that all UEs and all channels can use e.g. 24 Cell-specific Reference Signal (CRS) REs and 24 is to assume a maximum RS density with a demodulation reference signal (DMRS) RE of . However, based on our considerations, some UEs cannot benefit from increased RS density, but their performance will be affected. Also, some channels cannot benefit from increased RS density due to the impact on the code rate. Detailed considerations are provided below.

The first consideration is based on Physical Uplink Shared Channel (PUSCH) simulations for different repetition times and number of subframes combined at the receiver side for demodulation. FIG. 1 is a schematic diagram showing an example of Block Error Rate (BLER) characteristics of PUSCH repetition.

As shown in FIG. 1, FIG. 1(a) on the left and FIG. 1(b) on the right show simulation curves corresponding to two different repetition cases. In both cases, the horizontal axis represents the average signal-to-noise ratio (SNR), and the vertical axis represents the average BLER. The simulation parameters are specifically shown in the lower left corner of both FIG. 1(a) and FIG. 1(b). 1(a) and 1(b), except that the _number of repetitions in FIG. 1(a) is N _Rep =8 and the number of repetitions in FIG. are the same.

Also, as shown in the upper right corners of FIGS. 1(a) and 1(b), the parameter of _Nave determines the number of subframes synthesized at the receiver for joint channel estimation. represent. Specifically, in Fig. 1(a), for 8 repetitions, the dotted curve corresponds to the ideal channel estimation, and the three solid curves are combined at the receiver side for joint channel estimation. corresponds to realistic channel estimation when the number of subframes taken equals 1, 4 and 8, respectively. Similarly, in Fig. 1(b), for 128 repetitions, the dotted curve corresponds to the ideal channel estimation, and the three solid curves are combined at the receiver side for joint channel estimation. It corresponds to realistic channel estimation when the number of subframes is equal to 1, 4 and 8 respectively.

Intuitively, by comparing FIG. 1(a) and FIG. 1(b), for the same average BLER, regardless of ideal and realistic channel estimates, 8 repetitions is much larger than the average SNR of 128 repetitions. Also, the characteristic difference between the ideal channel estimation curve and the realistic channel estimation curve with synthesis of 4 or 8 subframes for 8 repetitions in Fig. 1(a) is , is smaller than the case of 128 times in FIG. 1(b). That is, the characteristic difference between the ideal channel estimation curve and the realistic channel estimation curve increases as the number of repetitions increases.

In particular, taking an average BLER=10 ⁻¹ as an example, by comparing the ideal channel estimation curve and the curve for N _ave =8, as indicated by the double arrows, the channel estimation gain is shown in FIG. It is easy to see that it is only about 1 dB for 8 repetitions as shown in (a) and reaches 6-7 dB for 128 repetitions as shown in FIG. 1(b). That is, the channel estimation gain is fairly limited when the number of repetitions is low, but becomes large when the number of repetitions is high.

Note that the simulation results are from uplink simulations, but the above considerations are also valid for the downlink. That is, the improvement in channel estimation performance significantly improves the BLER performance in low Signal to Interference plus Noise Ratio (SINR) scenarios (e.g., as shown in FIG. 1(b)), but ( For example, a relatively high SINR scenario (as shown in FIG. 1(a)) has less impact on the performance.

Therefore, from the above considerations, the SINR is relatively high as shown in FIG. , with relatively low SINR as shown in FIG. 1(b), it is meaningful to increase the RS density for higher repetition times or longer repetitions (higher coverage enhancement level).

A second consideration is based on the Enhanced Physical Downlink Control Channel (EPDCCH) example as follows.

As an example, assuming that the EPDCCH is transmitted in one PRB with 120 available REs, the downlink control information (DCI) size is determined by the Cyclic Redundancy Check (CRC). It is 26 bits, the modulation is QPSK (Quadrature Phase Shift Keying), and its equivalent code rate is very low, about 26/(120×2)=0.108. In that case, in order to increase the RS density, some REs allocated for transmitting data signals are usually used for transmitting RSs, which does not significantly affect the coding rate. is. For example, using 12 data REs to further transmit the RS changes the coding rate to 26/((120−12)×2=0.120, which is still very low. The amount of change in conversion rate is also very small, ie, 0.012.

As another example, assuming that the EPDCCH is transmitted in one Enhanced Control Channel Element (ECCE) that can carry 36 REs, the DCI size is also 26 bits with CRC, The modulation is QPSK and its equivalent code rate is 26/(36×2)=0.361, which is relatively high compared to the above example. In this case, replacing 3 or 6 data REs for RS REs yields 26/((36−3)×2)=0.394 or 26/((36−6)×2)=0.433 , which is also relatively high compared to the above example. Correspondingly, the amount of change in the coding rate is as high as 0.033 or 0.072. Therefore, replacing 3 or 6 data REs for RS REs has some impact on BLER performance. In that case, the channel estimation gain due to the increased RS density may be smaller than the loss caused by the increased code rate.

Thus, from the above considerations, it can be seen that for low code rates (eg, the previous example), it is more reasonable to increase the RS density than for high code rates (eg, the latter example). Because it has little impact on low code rates, User Equipment (UE) can benefit from improved channel estimation performance due to increased RS density.

Note that although the above discussion results are based on a downlink example, the above discussion is also valid for the uplink case.

Based on the above two considerations, when adopting an increase in RS density, it is necessary to consider the conditions under which an increase in RS density is meaningful in order to optimize the performance of the system as much as possible.

In one embodiment of the present disclosure, a wireless communication method 20 is provided as shown in FIG. FIG. 2 is a flow chart of a wireless communication method according to one embodiment of the present disclosure. As shown in FIG. 2, the wireless communication method 20 includes a step S201 of transmitting reference signals and data signals in PRBs at a coverage enhancement level. In wireless communication method 20, the number of resource elements for transmitting reference signals in PRBs is determined by the coverage enhancement level, channel type, and/or coding rate of the data signal.

Specifically, as described above, one PRB includes a total of 12×14 REs, some of which are assigned to transmit reference signals (RS), and others Some are used to transmit data signals. For example, the RS may be a DMRS used to demodulate a transmission containing data for the UE (receiver side). However, the RSs are not limited to specific RSs such as DMRSs, and may be all kinds of RSs. For example, if wireless communication method 20 is used in MTC, RS may be CRS.

Further, for example in MTC with coverage enhancement, a coverage enhancement level is defined to indicate the level or degree of coverage enhancement. The higher the coverage enhancement level, the greater the coverage enhancement. More specifically, when using repetitions to implement coverage enhancement, the coverage enhancement level may be represented by the number of repetitions. That is, the more repetitions that are used, the greater the coverage extension and thus the higher the level of coverage extension.

Further, with respect to repetition, it is well known that the repetition count indicates the number of times the RS and data signals are repeatedly transmitted in a subframe or PRB. One subframe consists of two slots, and each slot contains seven symbols in the time domain, which is the same as one PRB. However, one PRB corresponds to 12 subcarriers in the frequency domain and one subframe is bandwidth dependent in the frequency domain. Therefore, repetition in the subframe means repetition in the time domain only, and repetition in the PRB means repetition in both the time domain and the frequency domain. Note that, although not illustrated here, repetition may be performed only in the frequency domain.

Thus, according to one embodiment of the present disclosure, in wireless communication 20, the coverage enhancement level can be represented by the number of repetitions of transmission of reference and data signals in the time and/or frequency domain.

Repetition as one of the important techniques for coverage extension is only for explanation, the technique for coverage extension is not limited to repetition, even if other techniques are used to implement coverage extension. Good thing to note. When using other techniques, the coverage enhancement level may be represented by other parameters instead of the number of repetitions.

Also, the wireless communication method 20 is suitable for MTC, but is not limited to MTC. It can be applied to any wireless communication with coverage extension.

As described above, the number of REs transmitting RSs in a PRB may be determined by the coverage enhancement level, channel type, and/or coding rate of the data signal. That is, one or any combination of the three parameters are used to implement the RS density increase. Details of the three parameters will be described later.

In wireless communication 20, signal quality is improved and UE power consumption associated with coverage extension is reduced by increasing RS density based on coverage extension level, channel type, and/or coding rate of the data signal. .

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, the number of resource elements transmitting reference signals in PRBs for larger coverage enhancement levels is less than for smaller coverage enhancement levels. may be more.

Specifically, as seen in the first consideration above, as shown in FIG. In this case, increasing the RS density is meaningful, i.e. more RS REs in the PRB are used to transmit the RS, as the performance improvement will greatly improve its BLER performance. should. On the other hand, as shown in FIG. 1(a), communication with a small coverage extension level (for example, a small number of repetitions) has a relatively high SINR, and improvement in channel estimation performance has little effect on its BLER characteristics. and in this case it makes no sense to increase the RS density, ie less RS REs in the PRB should be used to transmit RSs.

For ease of understanding by those skilled in the art, the Physical Downlink Shared Channel (PDSCH) is taken as an example. Table 1 below shows an exemplary usage of REs for transmitting RSs in PRBs based on coverage enhancement levels.

In Table 1, the first line gives five different coverage enhancement levels 1-5 and the second line shows the RS configurations corresponding to coverage enhancement levels 1-5 respectively. Here, assume that coverage enhancement level 1 indicates the minimum level (eg, the minimum number of repetitions) and coverage enhancement level 5 indicates the maximum level (eg, the maximum number of repetitions).

For the minimum coverage enhancement level 1, the minimum number of REs in the PRB is used to transmit RSs, i.e., as mentioned above, the channel estimation gain due to increased RS density in this scenario is potentially , the minimum RS density is used. For example, as shown in Table 1, one or two DMRS ports, ie, 12 DMRS REs, are used here as RS REs.

For coverage enhancement level 2, which is greater than the lowest coverage enhancement level 1, the number of REs for transmitting RSs in a PRB can be increased compared to the lowest coverage enhancement level 1 case. For example, as shown in Table 1, 2 or 4 DMRS ports, ie, 24 DMRS REs are used here as RS REs. 24 DMRS REs is the maximum DMRS RE configuration.

For coverage enhancement level 3, which is greater than coverage enhancement level 2, the number of REs for transmitting RSs in PRBs can be further increased than for coverage enhancement level 2. For example, as shown in Table 1, in addition to 2 or 4 DMRS ports, ie 24 DMRS REs, 2 CRS ports, ie 16 CRS REs, are used here as RS REs. That is, in this case, there are a total of 40 RS REs in the PRB.

For coverage enhancement level 4, which is greater than coverage enhancement level 3, the number of REs for transmitting RSs in PRBs can be further increased than for coverage enhancement level 3. For example, as shown in Table 1, two or four DMRS ports, namely 24 DMRS REs and four CRS ports, namely 24 CRS REs, are used here as RS REs. That is, in this case, there are a total of 48 RS REs in the PRB. 24 CRS REs is the maximum configuration of CRS REs.

For maximum coverage enhancement level 5, the number of REs for transmitting RSs in PRBs can be further increased than for coverage enhancement level 4. For example, as shown in Table 1, in addition to the maximum configuration of DMRS REs, i.e. 24 DMRS REs and the maximum configuration of CRS REs, i.e. 24 CRS REs, the channel state information reference signal (CSI- An RE assigned to another RS, such as an RS (Channel State Information Reference Signal), can be used here as the RS's RE. That is, in this case, there are a total of 48 or more RS REs in the PRB.

With RS configurations based on the coverage enhancement levels in Table 1, UEs that cannot benefit from increased RS density experience no performance loss.

Note that the classification of coverage enhancement levels and corresponding RS configurations in Table 1 is for illustrative purposes only, and the present disclosure is not limited thereto. The classification of coverage enhancement levels and corresponding RS configurations may vary according to specific implementations.

Also, taking the PDSCH as an example, the determination of the number of REs of the RS in the PRB based on the coverage enhancement level has been specifically described, but the present invention is not limited to this. The present disclosure is also suitable for PUSCH, for example, and is applicable to any kind of downlink and uplink.

By determining the number of REs for RSs in PRBs based on the coverage enhancement level, wireless communication 20 may unnecessarily increase RS density, and UEs with lower coverage enhancement levels due to increased overhead and code rate can avoid affecting the original performance of

According to one embodiment of the present disclosure, in wireless communication 20 shown in FIG. 2, at least some of the reference signals transmitted in PRBs are existing CRS, DMRS, CSI-RS, and/or other existing reference Signals can be reused.

Reusing these existing RSs means not only using the allocated REs to transmit the existing RSs in PRBs, but also using these signals for channel estimation. Specifically, RE configurations in PRBs for legacy RSs such as CRS, DMRS, CSI-RS, etc. are predefined in the standard. These legacy RSs can be reused to increase RS density.

For example, for MTC UEs, the RSs used for MTC can reuse the existing CRS, DMRS, CSI-RS, depending on the specific requirement of increased RS density. That is, REs transmitting MTC RSs in PRBs can directly apply CRS REs, DMRS REs, CSI-RS REs, and the like. For example, as shown in Table 1, for coverage enhancement levels 1 and 2 DMRS are reused. If the RS density for coverage enhancement levels 3 and 4 needs to be increased, CRSs are additionally reused. DMRS, CRS and CSI-RS are all reused if the coverage enhancement level 5 RS density needs to be further increased. In addition to the REs of legacy RSs, the signals of these legacy RSs may be used directly for MTC.

By reusing legacy RSs for RSs in wireless communication 20, existing RSs can be utilized as much as possible and increasing the REs of many additional RSs is avoided, thus ensuring resource utilization. be.

According to one embodiment of the present disclosure, in wireless communication 20 shown in FIG. 2, at least some of the reference signals transmitted in PRBs may be transmitted on resource elements used to transmit data signals. .

Specifically, some REs allocated for transmitting data signals can be used to transmit RSs, for example, if legacy RSs cannot be used for MTC. For example, assume that only DMRS REs are available in the case of PDSCH in Table 1. Therefore, for coverage enhancement level 3, using the maximum configuration of DMRS REs, i.e., 24 DMRS REs plus 16 REs allocated for transmitting data signals, CRS REs RS can be sent instead. Coverage extension levels 4 and 5 are similar to coverage extension level 3.

Therefore, based on the availability of legacy RSs and the number of REs of RSs to be increased, all RSs reuse legacy RSs or some RSs reuse legacy RSs and the remaining RSs are in PRBs. or all RSs are transmitted in some data REs in a PRB.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, the number of resource elements transmitting reference signals in the PRBs for higher coding rates is less.

Specifically, as seen in the second consideration above, when increasing the RS density, there is little effect on low code rates, so , the increase in RS density becomes more reasonable. That is, when the coding rate is low, it is necessary to use REs of more RSs of PRBs to transmit RSs, and when the coding rate is high, it is necessary to use REs of RSs of fewer PRBs. must send the RS.

By determining the number of REs for RSs in PRBs based on the code rate, the wireless communication 20 avoids unnecessarily increasing the RS density and causing performance loss for UEs with high code rates. can do.

According to one embodiment of the present disclosure, in wireless communication 20 shown in FIG. 2, data signals are used for PDSCH or PUSCH transmission, and the usage of resource elements for transmitting reference signals in PRBs is physical downtime. It is indicated by the MCS indicated in DCI transmitted on a link control channel (PDCCH: Physical Downlink Control Channel) or EPDCCH.

Specifically, we continue with the example where the PDSCH is transmitted in one PRB with 120 available REs and the modulation is assumed to be QPSK, as can be readily understood by those skilled in the art. The usage (configuration) of the RS in this case can be indicated in the MCS indicated in the DCI transmitted on the PDCCH or EPDCCH. Next, Table 2 shows an example of increasing the RS density based on the coding rate indicated by the Modulation and Coding Scheme (MCS).

In Table 2, the first column lists the MCS indices 0-9 and the second column now gives the modulation order 2 for QPSK. In addition, the third column shows the Transport Block Size (TBS) indices 0-9 corresponding to the MCS indices 0-9 in the first column, respectively, with different sizes of data, i.e. different data bits. showing the number. Based on the conditions assumed above as well as the number of bits indicated by each TBS index, the corresponding code rate for each TBS index can be calculated by the same calculation method as in the second consideration above. The fourth column gives the calculated code rates corresponding to TBS indices 0-9 respectively. For example, TBS index 0 and MCS index 0 correspond to coding rate 0.067, TBS index 1 and MCS index 1 correspond to coding rate 0.1, TBS index 2 and MCS index 2 correspond to coding rate 0. .134, TBS index 3 and MCS index 3 correspond to coding rate 0.167, TBS index 4 and MCS index 4 correspond to coding rate 0.233, TBS index 5 and MCS index 5 correspond to Corresponding to coding rate 0.3, TBS index 6 and MCS index 6 correspond to coding rate N/A, TBS index 7 and MCS index 7 correspond to coding rate 0.433, TBS index 8 and MCS index 8 corresponds to coding rate 0.5, and TBS index 9 and MCS index 9 correspond to coding rate 0.567.

Based on the above discussion, the number of REs of RS in PRB for higher coding rate should be smaller than that for lower coding rate, and the increase of RS density is Therefore, the UE can benefit from the improved channel estimation due to the increased RS density without being affected by the increased code rate.

In Table 2, the fifth column gives the number of REs for the increased RS in different cases. Specifically, the maximum RE density increase is used when the code rates are as low as 0.067, 0.1, and 0.134, indicated by MCS indices 0, 1, and 2, respectively, i.e. , PRBs, 24 REs are added to transmit the RSs. For moderate cases of code rates 0.167, 0.233, and 0.3, denoted by MCS indices 3, 4, and 5, respectively, moderate RE density increases are used, i.e., RS 12 REs are added to transmit . If the code rate is as high as N/A, 0.433, 0.5, and 0.567, indicated by MCS indices 6, 7, 8, and 9, respectively, no increase in RE density is used, i.e. , PRBs to transmit RSs. Therefore, as shown in Table 2, the usage of REs to transmit RSs (or increased RS density) in PRBs can be indicated by MCS.

Note that the increased number of RS REs (eg, 24 or 12 REs) in Table 2 is for illustrative purposes only, and the present disclosure is not limited thereto. Also, although the PDSCH has been described here as an example, the present invention is not limited to this. The present disclosure is also suitable for PUSCH, for example, and is applicable to any kind of downlink and uplink data.

Furthermore, as mentioned above, the added 24 or 12 REs in this example may either reuse legacy RSs, be transmitted in some data REs of the PRB, or be part of legacy RSs. can be partially reused and partially transmitted in the RE for some data in the PRB.

By indicating the usage of REs to transmit RSs in PRBs by MCS, no new signaling needs to be set up to indicate the usage of RSs.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, the usage of resource elements for transmitting reference signals in PRBs may be configured by Radio Resource Control (RRC), It may be predefined or recommended by the user equipment via a Channel Quality Indicator (CQI).

Specifically, although an example was given above showing the usage of REs to transmit RSs in PRBs in the MCS, the invention is not so limited. The detailed usage of REs of increased RS may be configured by RRC or may be pre-defined. Alternatively, the UE may recommend increasing RS density via CQI. RRC and CQI are existing signaling like MCS, and their configuration is well known to those skilled in the art, so the details are not described here to avoid redundancy. Similarly, no new signaling needs to be set up to indicate RS usage in this case.

As mentioned above, the number of REs transmitting RSs in a PRB may be determined by the channel type of the data signal. That is, different channels may use different RS densities.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2 , the usage of resource elements that use data signals for transmission of PDCCH or EPDCCH and transmit reference signals in PRBs is defined in system information blocks ( SIB: System Information Block) or may be specified.

Specifically, take PDCCH and PDSCH as an example. In general, PDCCH has a very low coding rate, e.g., it is assumed to use one PRB to transmit 26 bits of DCI, whereas PDSCH uses a relatively high coding rate to ensure throughput. . In this case, PDSCH normally uses standard RS density and PDCCH may use increased RS density. Therefore, the channel characteristics of PDSCH are not affected. On the other hand, the PDCCH suffers little performance loss, but can benefit from improved channel estimation performance due to increased RS density.

Further, the detailed usage of the RS's REs for the PDCCH may be indicated by the SIB. Alternatively, the detailed usage of the RS's REs for the PDCCH may be specified, eg, in the specification. For example, for simplicity, a maximum RS density (eg, 24 CRS REs and 24 DMRS REs) may always be assumed for PDCCH. Thus, no new signaling needs to be set up to indicate the detailed usage of the RS's REs for the PDCCH.

Although PDCCH and PDSCH have been described here as examples, the invention is not so limited, for example, the above design is also suitable for EPDCCH.

According to one embodiment of the present disclosure, in wireless communication 20 shown in FIG. 2, data signals may be used for transmission of SIB1, and the usage of resource elements for transmitting reference signals in PRBs is determined by the master information block ( MIB: Master Information Block) or may be specified.

Specifically, SIB is taken as an example. It is well known that the UE does not know the coverage enhancement level before or during SIB reception. In this case, it is not possible to determine an increase in RS density for SIB1 based on the coverage enhancement level before reception and demodulation of SIB1. Therefore, if SIB1 is transmitted in the PRB, the specification may specify how to use the REs to transmit the RS. For example, for SIB1, a maximum RS density (eg, 24 CRS REs and 24 DMRS REs) may always be assumed.

Alternatively, the usage of REs to transmit RSs for SIB1 may be indicated in the MIB. In this case, the MIB can be first demodulated at the receiver side to obtain the RE usage for transmitting the RS for SIB1 indicated in the MIB for demodulation of SIB1. Then, the SIB1 is demodulated on the receiver side.

By indicating or specifying the RS's RE usage in the PRB for SIB1 in the MIB, there is no need to set up new signaling to indicate the detailed usage of the RS's REs for SIB1.

According to one embodiment of the present disclosure, in wireless communication 20 shown in FIG. 2, the usage of resource elements for transmitting reference signals in PRBs for other SIBs is denoted by SIB1.

Specifically, since other SIBs are obtained after SIB1, the RS's RE usage in PRBs for other SIBs may be indicated by SIB1. In this way, after SIB1 is received at the receiver side, the RS's RE usage in PRBs for other SIBs indicated by SIB1 can be obtained for decoding the other SIBs. Then another SIB can be obtained at the receiver side.

By indicating the RE usage of RSs in PRBs for other SIBs by SIB1, more flexible usage of RSs in SIBs is achieved.

Another embodiment of the present disclosure provides a wireless communication method 30 as shown in FIG. FIG. 3 is a flowchart of a wireless communication method according to another embodiment of the present disclosure; As shown in FIG. 3, the wireless communication method 30 includes receiving S301 reference signals and data signals in PRBs transmitted at a coverage enhancement level. In wireless communication method 30, the number of resource elements for transmitting reference signals in PRBs is determined by the coverage enhancement level, channel type, and/or coding rate of the data signal.

In wireless communication 30, signal quality is improved and UE power consumption associated with coverage extension is reduced by increasing the RS density based on the coverage extension level, channel type, and/or code rate of the data signal. .

According to one embodiment of the present disclosure, in wireless communication 30 shown in FIG. 3, the number of resource elements transmitting reference signals in PRBs for a larger coverage enhancement level is many.

According to one embodiment of the present disclosure, in wireless communication 30 shown in FIG. 3, the number of resource elements transmitting reference signals in PRBs for higher coding rates is Few.

It should be noted that other technical features of the wireless communication method 20 can also be incorporated into the wireless communication device 30 .

A further embodiment of the present disclosure provides a wireless communication device 40 as shown in FIG. FIG. 4 is a block diagram illustrating wireless communication device 40 according to a further embodiment of the present disclosure.

As shown in FIG. 4, wireless communication device 40 includes a transmitting unit 401 configured to transmit reference signals and data signals in PRBs at the coverage enhancement level. The number of resource elements for transmitting reference signals in a PRB is determined by the coverage enhancement level, channel type, and/or coding rate of the data signal.

The wireless communication device 40 according to the present disclosure processes various data within the wireless communication device 40 and executes related programs to control the operation of each unit (CPU: Central Processing Unit) 410, CPU 410 A read-only memory (ROM) 430 for storing various programs necessary for executing various processing and control by the CPU 410, and storing intermediate data temporarily generated in the procedure of processing and control by the CPU 410 and/or a storage unit 470 for storing various programs, data, and the like. The transmission unit 401, CPU 410, ROM 430, RAM 450, and/or storage unit 470, etc., are interconnected via a data and/or command bus 490 to transfer signals between them.

Each unit as described above is not intended to limit the scope of the present disclosure. According to one embodiment of the present disclosure, the functions of the transmission unit 401 may be realized by functional software in combination with the CPU 410, ROM 430, RAM 450, and/or storage unit 470, etc., above.

Wireless communication device 40 improves signal quality and reduces UE power consumption associated with coverage extension by increasing RS density based on coverage extension level, channel type, and/or code rate of data signal. be.

In yet another embodiment of the present disclosure, a wireless communication device 50 is provided as shown in FIG. FIG. 5 is a block diagram illustrating a wireless communication device 50 according to yet another embodiment of the present disclosure.

As shown in FIG. 5, wireless communication device 50 includes a receiving unit 501 configured to receive reference signals and data signals in PRBs transmitted at the coverage enhancement level. The number of resource elements for transmitting reference signals in a PRB is determined by the coverage enhancement level, channel type, and/or coding rate of the data signal.

The wireless communication device 50 according to the present disclosure processes various data in the wireless communication device 50 and executes related programs to control the operation of each unit. A ROM 513 for storing various programs necessary for , a RAM 515 for storing intermediate data temporarily generated by the processing and control procedures by the CPU 510, and/or a memory for storing various programs and data A unit 517 may also be included. The receiving unit 501, CPU 510, ROM 513, RAM 515, and/or storage unit 517, etc., are interconnected via a data and/or command bus 520 to transfer signals between them.

Each unit as described above is not intended to limit the scope of the present disclosure. According to one embodiment of the present disclosure, the functions of the receiving unit 501 may be realized by functional software in combination with the CPU 510, ROM 513, RAM 515, and/or storage unit 517, etc., above.

Wireless communication device 50 improves signal quality and reduces UE power consumption associated with coverage extension by increasing RS density based on coverage extension level, channel type, and/or coding rate of the data signal. be.

Note that the wireless communication device 40 and the wireless communication device 50 may be eNB (eNodeB), UE, etc., depending on the specific application scenario. Also, the technical features of the wireless communication methods 20 and 30 described above can be incorporated into the wireless communication devices 40 and 50 described above, respectively.

The present disclosure can be implemented in software, hardware, or software in cooperation with hardware. Each functional block used in the description of each embodiment described above can be implemented by an LSI as an integrated circuit, and each process described in each embodiment may be controlled by the LSI. They may be formed individually as chips, or one chip may be formed to include some or all of the functional blocks. They may include data inputs and outputs coupled thereto. Here, LSI may be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration. However, the method of realizing an integrated circuit is not limited to LSI, and may be realized using a dedicated circuit or a general-purpose processor. In addition, a field programmable gate array (FPGA) that can be programmed after the LSI is manufactured, or a reconfigurable that can reconfigure the connections and settings of circuit cells placed inside the LSI. A processor may be used.

It is intended, however, that the present disclosure may be variously changed or modified by those skilled in the art based on the descriptions presented herein and known techniques without departing from the spirit and scope of the present disclosure, Such modifications and adaptations fall within the scope of the protected claims. Furthermore, the constituent elements of the above-described embodiments can be arbitrarily combined without departing from the gist of the present disclosure.

Embodiments of the present disclosure may provide at least the following subject matter.

(1). transmitting reference signals and data signals in physical resource blocks (PRBs) at the coverage enhancement level;
A wireless communication method comprising:
The number of resource elements for transmitting reference signals in a PRB is determined by the coverage enhancement level, channel type, and/or coding rate of the data signal.

(2). The method of (1), wherein the number of resource elements transmitting reference signals in PRBs for higher coverage enhancement levels is greater than for lower coverage enhancement levels.

(3). At least part of the reference signal transmitted in the PRB is an existing cell-specific reference signal (CRS: Cell-specific Reference Signal), demodulation reference signal (DMRS: Demodulation Reference Signal), channel state information reference signal (CSI-RS : Channel State Information Reference Signal) and/or other existing reference signals.

(4). The method of (1), wherein at least some of the reference signals transmitted in PRBs are transmitted in resource elements used for transmitting data signals.

(5). The method of (1), wherein the number of resource elements transmitting reference signals in PRBs for higher code rates is less than for lower code rates.

(6). A data signal is used to transmit a physical downlink shared channel (PDSCH) or a physical uplink shared channel (PUSCH), and resource elements for transmitting reference signals in PRBs The usage is Downlink Control Information (DCI) transmitted on a Physical Downlink Control Channel (PDCCH) or an Enhanced Physical Downlink Control Channel (EPDCCH). The method according to (1), indicated by the indicated modulation and coding scheme (MCS: Modulation and Coding Scheme).

(7). The usage of resource elements for transmitting reference signals in the PRB is configured by Radio Resource Control (RRC) and predefined by the user equipment via Channel Quality Indicator (CQI) or The method described in (1), which is recommended.

(8). The data signal is used to transmit the PDCCH or EPDCCH, and the usage of resource elements to transmit the reference signal in the PRB is indicated or specified by a System Information Block (SIB) ( 1) The method described in 1).

(9). A data signal is used to transmit SIB1, and the usage of resource elements for transmitting reference signals in PRBs is indicated or specified by a Master Information Block (MIB), (1) The method described in .

(10). The method of (1), wherein the usage of resource elements for transmitting reference signals in PRBs for other SIBs is denoted by SIB1.

(11). 1. A wireless communication method comprising: receiving a reference signal and a data signal in a physical resource block (PRB) transmitted at a coverage enhancement level;
The number of resource elements for transmitting reference signals in a PRB is determined by the coverage enhancement level, channel type, and/or coding rate of the data signal.

(12). The method of (11), wherein the number of resource elements transmitting reference signals in PRBs for higher coverage enhancement levels is greater than for lower coverage enhancement levels.

(13). The method of (11), wherein the number of resource elements transmitting reference signals in PRBs for higher code rates is less than for lower code rates.

(14). 1. A wireless communications apparatus comprising: a transmitting unit configured to transmit reference signals and data signals in physical resource blocks (PRBs) at a coverage enhancement level,
The number of resource elements for transmitting reference signals in a PRB is determined by the coverage enhancement level, channel type, and/or coding rate of the data signal.

(15). 1. A wireless communication apparatus comprising: a receiving unit configured to receive a reference signal and a data signal in a physical resource block (PRB) transmitted at a coverage enhancement level;
The number of resource elements for transmitting reference signals in a PRB is determined by the coverage enhancement level, channel type, and/or coding rate of the data signal.

(16). The method according to (1), wherein the coverage enhancement level is represented by the number of repetitions of transmission of the reference signal and the data signal in the time domain and/or frequency domain.

The technical features of the wireless communication method can be incorporated into the wireless communication device as well. Further, embodiments of the present disclosure may also provide an integrated circuit including modules for performing the steps in each of the above wireless communication methods. Further, embodiments of the present invention also provide a computer readable storage medium storing a computer program comprising program code for performing the steps of each of the above wireless communication methods when run on a computing device. can.

Claims (20)

receiving a reference signal and a data signal based on a coverage enhancement level represented by the number of transmission repetitions;
and processing the received reference signal and the data signal;
The reference signal includes a cell-specific reference signal (CRS: Cell-specific Reference Signal), a demodulation reference signal (DMRS: Demodulation Reference Signal),
When the coverage extension level is 2 or more, the received reference signal has a constant density of the DMRS in one physical resource block (PRB), and the CRS is added.
wireless communication method. The number of resource elements of the reference signal used at the coverage enhancement level of 2 or higher is greater than the number of resource elements used at the coverage enhancement level of 1,
The wireless communication method according to claim 1. The number of resource elements used for transmission of the reference signal varies depending on the channel type,
The wireless communication method according to claim 1. The physical downlink control channel (PDCCH) reference signal density is higher than the physical downlink shared channel (PDSCH) reference signal density,
The wireless communication method according to claim 1. at least a portion of the received reference signal is received on a resource element used to receive the data signal;
The wireless communication method according to claim 1. The usage of the resource elements used to receive the reference signal is indicated by a System Information Block (SIB),
The wireless communication method according to claim 1. The usage of the resource elements used to receive the reference signal is received on a physical downlink control channel (PDCCH) or an enhanced physical downlink control channel (EPDCCH). indicated by the modulation and coding scheme (MCS: Modulation and Coding Scheme) indicated by the downlink control information (DCI: Downlink Control Information),
The wireless communication method according to claim 1. The usage of the resource elements used for reception of the reference signal may be configured or predefined by Radio Resource Control (RRC) or may be a Channel Quality Indicator (CQI). ) recommended by the user equipment via
The wireless communication method according to claim 1. In the receiving step, if a request for increasing the density of the reference signal is received, reuse the DMRS or the CRS;
The wireless communication method according to claim 1. a receiver that receives a reference signal and a data signal based on a coverage enhancement level represented by the number of transmission repetitions;
a processor for processing the received reference signal and the data signal;
with
The reference signal includes a cell-specific reference signal (CRS: Cell-specific Reference Signal), a demodulation reference signal (DMRS: Demodulation Reference Signal),
When the coverage extension level is 2 or more, the received reference signal has a constant density of the DMRS in one physical resource block (PRB), and the CRS is added.
wireless communication device. The number of resource elements of the reference signal used at the coverage enhancement level of 2 or higher is greater than the number of resource elements used at the coverage enhancement level of 1,
A wireless communication device according to claim 10 . The number of resource elements used for receiving the reference signal varies depending on the channel type,
A wireless communication device according to claim 10 . The physical downlink control channel (PDCCH) reference signal density is higher than the physical downlink shared channel (PDSCH) reference signal density,
A wireless communication device according to claim 10 . at least a portion of the received reference signal is received on a resource element used to receive the data signal;
A wireless communication device according to claim 10 . The usage of the resource elements used to receive the reference signal is indicated by a System Information Block (SIB),
A wireless communication device according to claim 10 . The usage of the resource elements used to receive the reference signal is received on a physical downlink control channel (PDCCH) or an enhanced physical downlink control channel (EPDCCH). indicated by the modulation and coding scheme (MCS: Modulation and Coding Scheme) indicated by the downlink control information (DCI: Downlink Control Information),
A wireless communication device according to claim 10 . The usage of the resource elements used for reception of the reference signal may be configured or predefined by Radio Resource Control (RRC) or may be a Channel Quality Indicator (CQI). ) by or recommended by the User Equipment via
A wireless communication device according to claim 10 . When the receiving unit receives a request to increase the density of the reference signal, reuse the DMRS or the CRS;
A wireless communication device according to claim 10 . A transmission/reception method executed in a communication system having a base station device and a terminal device,
Reference signals including cell-specific reference signals (CRS) and demodulation reference signals (DMRS) from the base station apparatus based on the coverage extension level represented by the number of transmission repetitions and a data signal to the terminal device;
receiving the reference signal and the data signal at the terminal device;
When the coverage extension level is 2 or more, the reference signal received by the terminal device has a constant density of the DMRS in one physical resource block (PRB), and the CRS is added. be,
How to send and receive. Based on the coverage extension level represented by the number of transmission repetitions, transmit reference signals including cell-specific reference signals (CRS) and demodulation reference signals (DMRS) and data signals. a base station device comprising a transmitter for
a terminal device including a receiving unit that receives the reference signal and the data signal;
with
When the coverage extension level is 2 or more, the reference signal received by the terminal device has a constant density of the DMRS in one physical resource block (PRB) and the CRS is added. be,
wireless communication system.

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