Reference signals with different resource densities

Abstract

A wireless communication method includes transmitting, from a first communication device to a second communication device, an indication of N regions in a resource grid defined by transmission resources in a frequency domain and / or time resources in a time domain, and transmitting a reference signal between the first communication device and the second communication device according to density information. Here, each of the N regions has a corresponding resource density indicating a time-frequency resource density configured for the reference signal transmission, and N is an integer greater than 1.

Description

Technical Field

[0001] This document relates to systems, devices, and techniques for wireless communications. Background Art

[0002] Efforts are currently underway to define the next generation of wireless communication networks that will provide greater deployment flexibility, support a wide range of devices and services, and employ different technologies to efficiently utilize bandwidth. Summary of the invention

[0003] Various methods and apparatus are described for implementing different reference signal densities in a wireless communication system.

[0004] In one example aspect, a method of wireless communication is disclosed. The method includes: sending an indication of N zones in a resource grid defined by transmission resources in the frequency domain and / or time resources in the time domain from a first communication device to a second communication device, and transmitting a reference signal between the first communication device and the second communication device based on the density information. Here, each of the N zones has a corresponding resource density indicating a time-frequency resource density configured for reference signal transmission, and N is an integer greater than 1.

[0005] In another example aspect, a method of wireless communication is disclosed. The method includes: a second communication device receiving an indication of N zones in a resource grid defined by transmission resources in the frequency domain and / or time resources in the time domain from a first communication device, and transmitting a reference signal between the first communication device and the second communication device based on the density information. Here, each of the N zones has a corresponding resource density indicating a time-frequency resource density configured for reference signal transmission, and N is an integer greater than 1.

[0006] In yet another example aspect, a wireless communication apparatus is disclosed, comprising a processor configured to execute the methods described herein.

[0007] In another example aspect, the various techniques described herein may be embodied as processor-executable code and stored in a computer-readable program medium.

[0008] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 An example of a typical frequency spectrum of a wireless signal is shown.

[0010] Figure 2 An example of a configuration in which downlink to uplink interference may occur on the network side is shown.

[0011] Figure 3An example of a configuration in which downlink to uplink interference may occur on the network side is shown.

[0012] Figure 4 An example of a configuration in which uplink to downlink interference may occur on the wireless device side is shown.

[0013] Figure 5 An example of a configuration in which uplink to downlink interference may occur on the wireless device side is shown.

[0014] Figure 6 An example of transmission resources configured for reference signal transmission is shown.

[0015] Figure 7 An example of transmission resources configured for reference signal transmission is shown.

[0016] Figure 8 An example of transmission resources configured for reference signal transmission is shown.

[0017] Fig. 9 An example of transmission resources configured for reference signal transmission is shown.

[0018] Fig.10 An example of transmission resources configured for reference signal transmission is shown.

[0019] FIG. 11A to FIG. 11B is a flow chart of an example wireless communication method performed by a network device.

[0020] Fig.12 is a block diagram of an example of a wireless communication device.

[0021] Fig.13 An example of a wireless communication network is shown. DETAILED DESCRIPTION

[0022] The section headings used in this document are intended only to improve readability and are not intended to limit the scope of the embodiments and techniques disclosed in each section to that section. In addition, for ease of understanding, some embodiments are described with reference to the Third Generation Partnership Project (3GPP) New Radio (NR) standard ("5G"), and the described techniques may be implemented in different wireless systems that implement protocols other than the 5G protocol.

[0023] In existing NR systems, various reference signals have been specified to measure interference in wireless communications, such as demodulation reference signal (DM-RS), channel state information reference signal (CSI-RS) and sounding reference signal (SRS). A typical reference signal is a signal whose properties are predefined so that the receiver of the reference signal knows what to expect. Existing reference signals are usually configured to have the same frequency density in the frequency domain. For example, frequency density can be measured based on the number of subcarriers or resource blocks allocated to the reference signal per unit frequency.

[0024] However, for scenarios with different interference in the frequency domain, such as sub-band full-duplex and dynamic time division duplex (TDD), configuring reference signals with the same frequency density over the entire frequency bandwidth may result in undesirable resource overhead. For example, in a spectrum with strong or dynamic interference, it may be better to allocate a higher frequency density for reference signal transmission, for example, to be able to characterize and calibrate this part of the spectrum more accurately and quickly. On the contrary, in spectrum areas with lower and stable interference, it may be more appropriate for the reference signal to have a lower frequency density in order to save transmission resources for other transmissions such as data transmission. If the interference is different in the time domain, a similar problem exists in the time domain. However, today's systems fail to recognize this need and therefore do not provide a way for wireless communication systems to configure and use reference signal transmissions with different resource densities (e.g., time or frequency density).

[0025] This document discloses various techniques that embodiments may use, among other things, to configure and use reference signals with different frequency or time resource densities.

[0026] 1. Preliminary Discussion

[0027] In wireless communications, signals need to be filtered before they are transmitted through the medium in order to limit the transmitted signal power to the desired frequency range. Ideally, after filtering, there should be no leakage signal outside the desired frequency range. However, due to limitations in technology and implementation complexity, there is usually non-zero signal power outside the desired frequency range, sometimes called a leakage signal. Figure 1 An example of a typical output signal after the filtering operation is shown. Figure 1In FIG. 1 , the horizontal axis represents frequency, and the vertical axis represents signal power. For a desired signal with a center frequency of f and a bandwidth of B, the leakage signal in the bandwidth B adjacent to the desired signal (i.e., from f-3B / 2 to fB / 2 and from f+B / 2 to f+3B / 2) is stronger than the leakage signal in the bandwidth B far from the desired signal (e.g., from f-5B / 2 to f-3B / 2 and from f+3B / 2 to f+5B / 2). At the same time, the leakage signal in the bandwidth B adjacent to the desired signal is more dynamic. The leakage signal will interfere with the desired signal in the frequency resources from f-5B / 2 to fB / 2 and from f+B / 2 to f+5B / 2. This is also called a "roll-off filter".

[0028] In order to help demodulate the desired signal and ensure the best operation of the channel between the transmitter and the receiver, the receiver usually measures interference. Transmitting reference signals helps interference measurement. However, reference signal transmission occupies bandwidth for other traffic (such as user data). Therefore, reference signal transmission is usually performed only at some frequencies and some opportunities, and the channel estimate obtained by receiving the reference signal at these times or frequencies is interpolated to obtain the channel estimate over the entire relevant frequency band and the entire time period. If the reference signal is frequently transmitted in the time domain or closely transmitted in the frequency domain, the receiver can measure the interference more accurately, thereby demodulating the desired signal more accurately. However, transmitting more reference signals will result in more resource overhead. To cope with this situation, the transmitter can transmit more reference signals in frequency resources with strong dynamic interference (e.g., from f-3B / 2 to fB / 2 and from f+B / 2 to f+3B / 2), and transmit fewer reference signals in frequency resources with lower and stable interference (e.g., from f-5B / 2 to f-3B / 2 and from f+3B / 2 to f+5B / 2).

[0029] In some embodiments, for example, using the Orthogonal Frequency Division Multiplexing Access (OFDMA) scheme defined by 3GPP for Long Term Evolution (LTE) or NR technology, available transmission resources can be defined on a grid in the time domain and the frequency domain. In such a system, the transmitter sends a reference signal to the receiver in one or more resource elements. Each resource element is uniquely identified by an index in the frequency domain and an index in the time domain, where the index in the time domain refers to the symbol position in the time domain relative to a reference point.

[0030] The reference signal has different frequency density in the frequency domain. The receiver measures the reference signal to help demodulate the desired signal or monitor interference status.

[0031] In various embodiments, the techniques described herein may be implemented in a transmitter-receiver configuration as follows.

[0032] -The transmitter is a base station and the receiver is a user equipment (UE). In this case, the UE uses the reference signal to demodulate the downlink (DL) signal.

[0033] -The transmitter is the UE and the receiver is the base station. In this case, the base station uses the reference signal to demodulate the uplink (UL) signal.

[0034] -The transmitter is a base station and the receiver is also a base station. In this case, the reference signal is used for interference measurement between base stations.

[0035] - The transmitter is a UE and the receiver is also a UE. In this case, the reference signal is used for interference measurement between UEs.

[0036] 2. Example of different zones with different resource densities

[0037] In a sub-band full-duplex system, the base station can transmit and receive simultaneously. Figure 2 It is an example of a sub-band full-duplex system on the base station side. Figure 2 An example of a two-dimensional resource grid is shown, where the horizontal axis represents time (in time slots) and the vertical axis represents the frequency domain. A similar visual presentation scheme is also used for Figures 3 to 6 , where the additional reference signal resources are shown by oblique hatching. The area allocated to uplink transmission is shown by horizontal hatching, and the area allocated to downlink transmission is shown by vertical hatching. In this example, the bandwidth of the uplink frequency resources in time slots 1 / 2 / 3 is approximately twice the bandwidth of the downlink frequency resources. There is a guard band between the downlink resources and the uplink resources in time slots 1 / 2 / 3. The guard band can be several resource blocks (RBs) or zero RBs. During time slots 1, 2, and 3, the base station needs to send and receive simultaneously. However, in time slot 0, the base station only needs to send because only downlink resources are allocated at the base station. Similarly, in time slot 4, the base station only needs to receive because only uplink resources are allocated at the base station.

[0038] The power of the transmitted signal on the base station side is much higher than the power of the received signal. There may be interference from the downlink to the uplink because the leakage signal from the transmitted signal falls into the received signal. Due to the "roll-off filter", the interference from the downlink to the uplink may be stronger and more dynamic in the area closer to the downlink resources (i.e., the first area), while the interference may be reduced and flattened in the second area. Therefore, the reference signal in the first area may have a higher frequency density in the frequency domain, while the reference signal in the second area may have a lower frequency density.

[0039] Figure 3 It is another example of a sub-band full-duplex system on the base station side. Downlink resources are configured on both sides of the uplink resources. In this example, the bandwidth of the uplink frequency resources in time slots 1 / 2 / 3 is approximately 3 times the bandwidth of the downlink frequency resources on each side. Due to the "roll-off filter", the downlink interference to the uplink may be stronger and more dynamic in the areas closer to the downlink resources (i.e., the first area and the third area), while the interference can be reduced and flattened in the second area. Therefore, the reference signals in the first area and the third area may have a higher frequency density in the frequency domain, while the reference signals in the second area may have a lower frequency density.

[0040] Figure 4 is an example of a sub-band full-duplex system on the UE side. UE#1 and UE#2 operate on the same carrier, for example, both operate in a 60MHz bandwidth in the 2.6GHz band. The UE operates in half-duplex mode, which means that the UE cannot transmit and receive at the same time. In time slots 1 / 2 / 3, UE#1 is receiving downlink, while UE#2 is transmitting uplink. Similarly, the power of the transmitted signal of UE#2 is much higher than the power of the received signal of UE#1. There may be uplink interference to downlink because if UE#1 is physically close to UE#2, the leakage signal from the transmitted signal of UE#2 will fall into the received signal of UE#1.

[0041] In this example, the bandwidth of the downlink frequency resources in time slots 1 / 2 / 3 is approximately twice the bandwidth of the uplink frequency resources. Due to the "roll-off filter", the uplink interference to the downlink may be stronger and more dynamic in the area closer to the uplink resources (i.e., the first area). The interference may be reduced and flattened in the second area. Therefore, the reference signal in the first area may have a higher frequency density in the frequency domain, while the reference signal in the second area may have a lower frequency density.

[0042] Figure 5 is another example of a sub-band full-duplex system on the UE side. The UE is able to transmit and receive simultaneously in time slots 1 / 2 / 3. Similarly, the power of the transmitted signal is much higher than the power of the received signal. Since the leakage signal of the transmitted signal falls into the received signal, there may be uplink interference to the downlink. Due to the "roll-off filter", the uplink interference to the downlink may be stronger and more dynamic in the area closer to the uplink resource (i.e., the first area). The interference can be reduced and flattened in the second area. Therefore, the reference signal in the first area may have a higher frequency density in the frequency domain, while the reference signal in the second area may have a lower frequency density.

[0043] Although this article only describes the example of sub-band full-duplex, if the interference characteristics (such as strength and change rate) on different frequency resources are different, reference signals with different frequency densities can be applied to any scenarios, such as full-duplex systems, dynamic TDD systems, TDD systems with different time slot formats between cells, and cells with co-channel or adjacent channel interference.

[0044] Although only 2 or 3 areas are described here as examples, the number of areas can be greater than 3. In practice, the number of areas should be determined by the interference and implementation algorithms. For example, if the interference characteristics of the 4 areas are significantly different, 4 areas can be configured.

[0045] The base station configures and indicates N regions to the UE or the base station, each region being associated with a frequency density of the reference signal. N is an integer greater than 1. If the regions are configured for downlink, the base station transmits a reference signal with a corresponding frequency density associated with each region. If the regions are configured for uplink, the UE transmits a reference signal with a corresponding frequency density associated with each region.

[0046] Each region may be determined by frequency domain resources (or simply referred to as frequency resources) and time domain resources. The frequency domain resources of a region may be determined by one of the following alternatives.

[0047] Alternative 1: The base station configures frequency resources associated with each region. Each region may have one or more RBs or resource block groups (PRGs).

[0048] Alternative 2. The base station configures the number of zones. The base station and / or UE determines the frequency resources for each zone based on the number of zones and the total number of downlink or uplink RBs / PRGs. For example, if the total number of uplink RBs is 90 RBs and the number of zones is 3, each zone contains 30 RBs. If the total number of RBs is not divisible by the number of zones, a specific rule may be used to determine the number of RBs for each zone. For example, the first (or last) zone may have fewer RBs, while all other zones may have the same number of RBs. If the total number of uplink RBs is 86 RBs and the number of zones is 3, the first zone and the second zone will have RBs, and the third region will have 86-29*2=28 RBs. Represents the ceiling function.

[0049] The time domain resources of a region can be determined by one of the following alternatives.

[0050] Alternative 1. The base station does not configure any time domain resources for each zone. In this case, all time slots / symbols are associated with each zone. For example, if two zones are configured for uplink, all uplink time slots / symbols are associated with these two zones.

[0051] Alternative 2: The base station does not configure any time domain resources for each zone. In this case, for a sub-band full-duplex system, all time slots / symbols that the base station or UE can transmit and receive simultaneously are associated with each zone. Figure 2 For example, if the base station does not configure time domain resources for the first area and the second area, this means that all three time slots (time slot 1, time slot 2 and time slot 3) are associated with the first area and the second area, because the base station can send and receive simultaneously in these three time slots.

[0052] Alternative 3: The base station configures time domain resources for these areas. Time domain resources can be configured in units of frames, subframes, time slots, sub-time slots, symbols, seconds or milliseconds. Taking the figure as an example, time slot 2 is configured as the time domain resource of the first area and the second area.

[0053] The frequency density of the reference signal indicates the density of the reference signal in the frequency domain. The frequency density of each region can be determined by one of the following alternatives.

[0054] Alternative 1: Base stations are configured with frequency density associated with each region. Figure 2 For example, the base station can configure the frequency density of the first area to "4", which means that 4 REs in each RB send reference signals. The base station can configure the frequency density of the second area to "2", which means that only 2 REs in each RB send reference signals. The densities "4" and "2" here are just example values. The base station can use other values / parameters to indicate the density, as long as the base station and the UE understand it.

[0055] Alternative 2. The base station configures the frequency density associated with a reference area and configures another scaling factor for another area. Figure 2 For example, the base station may configure the frequency density of the first area to be "4" and the scaling factor of the second area to be "1 / 2". Therefore, it can be concluded that the frequency density of the second area is "2".

[0056] Alternative 3. The frequency density for each area is specified in the specification.

[0057] Alternative 4: The frequency density of each area is indicated or updated by a Media Access Control Control Element (MAC-CE).

[0058] Below are some examples of frequency density.

[0059] 1. Send a reference signal in each RE of each RB in the area;

[0060] 2. Send a reference signal in each odd RE (or even RE) of each RB in the region;

[0061] 3. Send a reference signal in the sixth RE of an odd-numbered RB in the region;

[0062] 4. A reference signal is sent in the second RE and the eighth RE of every 6 RBs in a region, for example, an RB with RB index m and mmod6=1.

[0063] The transmitter sends a reference signal with a specific frequency density, and the receiver determines the frequency resource of the reference signal based on the frequency density. Then, the receiver can measure the reference signal in the determined corresponding frequency resource.

[0064] If the frequency resource of the reference signal is completely within one region, the frequency density of the reference signal is the frequency density associated with the region.

[0065] If the frequency resources of the reference signal span more than one region, one of the following alternatives may be applied.

[0066] Alternative 1. The frequency density of the associated area is used for the frequency resources of the reference signal within the associated area. Therefore, one reference signal can have multiple frequency densities.

[0067] Alternative 2. The frequency density of the reference signal is determined by the frequency density associated with the region overlapped by the lowest RB of the reference signal.

[0068] Alternative 3. The frequency density of the reference signal is determined by the frequency density associated with the region overlapped by the highest RB of the reference signal.

[0069] Alternative 4. The frequency density of the reference signal is determined by the frequency density associated with the region with the lowest index that overlaps the reference signal.

[0070] Alternative 5. The frequency density of the reference signal is determined by the frequency density associated with the region with the highest index that overlaps with the reference signal.

[0071] Alternative 6. The frequency density of the reference signal is determined by the frequency density associated with the region with the highest frequency that overlaps with the reference signal.

[0072] Alternative 7. The frequency density of the reference signal is determined by the frequency density associated with the region with the lowest frequency that overlaps with the reference signal.

[0073] by Figure 6 For example, there are a total of 8 RBs in the frequency domain, which are divided into two regions, namely the first region and the second region. The reference signal is transmitted in 8 RBs. The frequency density of the first region is higher than the frequency density of the second region. In the first region, the reference signal is transmitted in the odd REs of all 4 RBs. In the second region, the reference signal is transmitted in the first RE, the fifth RE, and the ninth RE of all 4 RBs.

[0074] Figure 7 is another example. Similarly, there are a total of 8 RBs in the frequency domain, which are two regions, namely the first region and the second region. In the first region, the reference signal is transmitted in each RE of all 4 RBs. In the second region, the reference signal is transmitted in each RE of the even-numbered RBs.

[0075] The reference signal can be transmitted together with the data channel (e.g., Physical Downlink Shared Channel (PDSCH) or Physical Uplink Shared Channel (PUSCH)), which can be similar to the existing DMRS for PDSCH and PUSCH. The resources of the reference signal cannot be used for the data channel. In other words, the data channel is then mapped to the RE, and the data channel is not mapped to these REs used for the reference signal.

[0076] In this case, the reference signal is transmitted within the frequency resources of the data channel. The reference signal is transmitted in one or more symbols of the data channel. If the data channel is transmitted entirely in one region, the frequency density of the reference signal is the frequency density associated with that region. If the data channel is transmitted on more than one region, the frequency density of the associated region is used for the frequency resources of the reference signal within the associated region. Thus, one reference signal can have multiple frequency densities.

[0077] by Figure 8 For example, there are 8 RBs in total. Each RB has 12 REs. The lower 4 RBs are located in the first region, and the other 4 RBs are located in the second region. PUSCH is scheduled in the lower 6 RBs and transmitted in all 14 symbols in the time domain. The third symbol is used to transmit DMRS, and the reference signal for interference measurement is transmitted in the fourth symbol. Since PUSCH is transmitted across 2 regions, the frequency density of reference signals in different regions is different. In the first region, the frequency density is higher, that is, the reference signal is transmitted in the odd REs of all 4 RBs. In the second region, the reference signal is transmitted in the first RE, the fifth RE, and the ninth RE in the fifth and sixth RBs.

[0078] 3. Example of dynamic indication of frequency density

[0079] Method #1: Dynamic indication of frequency density.

[0080] The base station configures and indicates N areas to the UE, where N is an integer greater than 1. Downlink Control Information (DCI) indicates the frequency density of the data channel.

[0081] If the data channel is transmitted entirely within one area, the DCI indicates the corresponding frequency density of the reference signal transmitted with the data channel. The frequency density may be transmitted directly by the DCI, or may be configured by Radio Resource Control (RRC) signaling and indicated by the DCI. In the case of low interference or no interference, the DCI may also indicate that no reference signal is transmitted with the data channel. This may be determined by an interference threshold configured by RRC signaling, such as a Reference Signal Receiving Power (RSRP) or a Received Signal Strength Indicator (RSSI) threshold. If the interference is less than the threshold, no reference signal is required. For example, if the RRC configures 4 frequency densities {4, 2, 1, 0}, "4", "2" or "1" means that 4 REs, 2 REs or 1 RE are used for reference signals in each RB, respectively. "0" means that no reference signal is transmitted with the data channel.

[0082] If the data channel is transmitted on more than one region, the DCI indicates the corresponding frequency density of the reference signal for each region. RRC signaling configures the association between the index and the corresponding frequency density for each region. The DCI indicates the index so that the UE can determine the corresponding frequency density for each region.

[0083] by Figure 8 For example, RRC signaling configures the following association between the index and the corresponding frequency density for each area. Similarly, "0" means that there is no reference signal in the corresponding area. Figure 8 In the DCI, the DCI indicates the UE index 0. Therefore, the UE transmits the PUSCH according to the frequency density associated with the index 0, that is, the first region is 6 and the second region is 3. As shown in Table 1.

[0084] Table 1

[0085] index Frequency Density 0 The first area is 6 and the second area is 3. 1 The first area is 6 and the second area is 1. 2 The first area is 6 and the second area is 0. 3 The first area is 0 and the second area is 0.

[0086] Method #2: Dynamic indication of frequency resources and frequency density of an area.

[0087] The DCI indicates the frequency resources of the region and the frequency density of the data channel. One of the following alternatives may be used to indicate the frequency resources and frequency density of the region.

[0088] Alternative 1. RRC signaling configures a first index associated with the frequency resource partitioning of each region and a second index associated with the frequency density. The DCI indicates the first index and the second index to the UE, so that the UE can determine the frequency density of the corresponding frequency resources. The frequency resource partitioning of each region is configured by one of the alternatives in Embodiment 2.

[0089] For example, each region may be determined by frequency domain resources (or simply referred to as frequency resources) and time domain resources. The frequency domain resources of a region may be determined by one of the following alternatives.

[0090] Alternative 1. The base station configures the frequency resources associated with each region. Each region may have one or more RBs or PRGs.

[0091] Alternative 2. The base station configures the number of zones. The base station and / or UE determines the frequency resources for each zone based on the number of zones and the total number of downlink or uplink RBs / PRGs. For example, if the total number of uplink RBs is 90 RBs and the number of zones is 3, each zone contains 30 RBs. If the total number of RBs is not divisible by the number of zones, a specific rule may be used to determine the number of RBs for each zone. For example, the first (or last) zone may have fewer RBs, while all other zones may have the same number of RBs. If the total number of uplink RBs is 86 RBs and the number of zones is 3, the first zone and the second zone will have RBs, and the third region will have 86-29*2=28 RBs.

[0092] Alternative 2. RRC signaling configures an index associated with the frequency resource partitioning for each region and the corresponding frequency density. The DCI indicates the index to the UE, and the UE can determine the frequency density of the corresponding frequency resource. The frequency resource partitioning for each region is configured by one of the alternatives in embodiment 2.

[0093] by Figure 8 For example, as shown below, RRC signaling configures an index associated with the frequency resource partition for each region and the corresponding frequency density. In this example, the DCI indicates index 0 to the UE. Therefore, the frequency resources are divided into two regions, and the frequency resources of each region can be determined, for example, each region has the same number of RBs. Table 2 shows an example of resource density in this case.

[0094] Table 2

[0095]

[0096] Method #3: Other sample methods

[0097] The following methods can also be used to indicate frequency density.

[0098] Method 3-1: DCI indicates the number of frequency densities. If the DCI indicates M as the number of frequency densities, where M is an integer greater than 1, the frequency resources of the scheduled data channel are divided into M regions. For example, if the total number of RBs of the scheduled data channel is 90 RBs and the number of regions is 3, each region contains 30 RBs. If the total number of RBs cannot be divided by the number of regions, a specific rule can be used to determine the number of RBs in each region. For example, the first (or last) region can have fewer RBs, while all other regions can have the same number of RBs. If the total number of uplink RBs is 86 RBs and the number of regions is 3, the first region and the second region will have The first region will have 86-29*2=28 RBs, while the third region will have 86-29*2=28 RBs. The frequency density of each region is configured by RRC signaling or specified in the specification.

[0099] Method 3-2: DCI indicates the number of frequency densities If DCI indicates M frequency densities, where M is an integer greater than 1, the frequency resources of the scheduled data channel are divided into M regions.

[0100] 4. Time Domain Resource Example

[0101] The reference signal can be transmitted in one or more symbols within the scheduled data channel. DMRS is used to measure the channel state. In order to facilitate PDSCH demodulation, the DMRS symbol or at least some DMRS symbols are located in front of the scheduled PDSCH / PUSCH. For type A PDSCH / PUSCH scheduling, the DMRS is usually at the third or fourth symbol of the time slot (counting from the first symbol). For type B PDSCH / PUSCH scheduling, the DMRS is usually at the first symbol of the scheduled PDSCH / PUSCH.

[0102] The reference signal is used to measure interference, thereby helping demodulate the data channel. In order to facilitate demodulation of the data channel (eg, obtain interference measurement results earlier) and ensure the accuracy of interference measurement, the reference signal is placed adjacent to the DMRS through the following alternative scheme.

[0103] Alternative 1: Place the reference signal in the next symbol of DMRS If two consecutive symbols are used as DMRS, place the reference signal in the symbol next to the last DMRS symbol.

[0104] Alternative 2: Place the reference signal in the symbol preceding the DMRS If two consecutive symbols are used as DMRS, place the reference signal in the symbol preceding the first DMRS symbol.

[0105] Depending on the configuration, the DMRS symbol may also be transmitted in the middle or end portion of the scheduled data channel. The reference signal may be configured in the next symbol or the previous symbol of one or more DMRS symbols.

[0106] by Figure 8 For example, only one symbol DMRS is transmitted, and the reference signal is transmitted in the next symbol of DMRS.

[0107] by Fig. 9 For example, a total of 4 symbols are transmitted, and these 4 symbols are divided into two groups. The first group of DMRS symbols is at the front and occupies two consecutive symbols. The second group of DMRS symbols is at the end and also occupies two consecutive symbols. In this example, the reference signal is transmitted in the next symbol of the last DMRS symbol of each group of DMRS symbols.

[0108] 5. Example of a sequence transmitted via a reference signal

[0109] The transmitter does not send any signal on these resources of the reference signal, so the receiver can use it to measure the interference status.

[0110] Alternatively, the transmitter may send the following sequence on these resources of the reference signal.

[0111] Alternative 1. Pseudo-random sequence;

[0112] Alternative 2: Low peak to average power ratio (PAPR) sequence, such as Zadoff-Chu sequence;

[0113] Alternative 3: Reuse the DMRS sequence;

[0114] Alternative 4. Reuse the sequence of SRS;

[0115] Alternative 5. Reuse the sequence of CSI-RS.

[0116] 6. Examples of different temporal densities of reference signals

[0117] The interference between different symbols / time slots can also be different. Figure 2For example, the interference in time slot 0 or time slot 4 is lower than that in time slot 1, time slot 2 or time slot 3, because there is interference from downlink to uplink on the base station side, and there is interference from uplink to downlink on the UE side. Therefore, the reference signal also has different time densities in the time domain. For example, in time slot 0 and time slot 4, the reference signal is transmitted in two symbols in each time slot. In time slot 1, time slot 2 and time slot 3, the reference signal is transmitted in four symbols in each time slot.

[0118] Different methods may be applied to configure or indicate different time densities of reference signals.

[0119] Method #1: The base station configures different time zones and time densities associated with the time zones.

[0120] A time zone contains one or more symbols / time slots and can be defined as a time domain pattern. Fig.10 In the example, the first time domain pattern may be time slot 0 and time slot 4 in each cycle, and the cycle is 5 time slots. The second time domain pattern may be time slot 1, time slot 2, and time slot 3 in each cycle.

[0121] If the reference signal is transmitted in one time zone, the time density of the reference signal is determined by the time zone in which the reference signal is transmitted.

[0122] If the reference signal is transmitted across more than one time zone, the temporal density of the reference signal is determined by the following alternatives.

[0123] Alternative 1. The temporal density of the reference signals is determined by the time zones in which the reference signals are transmitted.

[0124] Alternative 2. The time density of the reference signal is determined by the time region overlapping with the first symbol of the reference signal.

[0125] Alternative 3. The time density of the reference signal is determined by the time region overlapping with the last symbol of the reference signal.

[0126] Method #2: The base station indicates the time density of the reference signal via DCI or MAC-CE.

[0127] RRC signaling configures a set of configurations for the UE, which includes an index and a corresponding time density associated with the index. The DCI or MAC-CE indicates the index to the UE. The UE determines the time density of the reference signal based on the indication. One of the indices indicates that the reference signal is not transmitted.

[0128] For example, RRC signaling configures the following association for the UE. Index 0 refers to time density "4", which means that the reference signal is transmitted in 4 symbols in each time slot. There are many common solutions to determine which 4 symbols to use, such as the first and second symbols configured by RRC signaling plus the last and second to last symbols of the scheduled data channel. Index 3 refers to time density 0, which means that the reference signal is not transmitted. Table 3 shows an example of such a configuration.

[0129] Table 3

[0130]

[0131]

[0132] The DCI or MAC-CE may also indicate more than one time density to the UE. If the DCI schedules PDSCH / PUSCH with N-1 repetitions (thus a total of N PDSCH / PUSCH transmissions), or if the DCI schedules N PDSCH / PUSCH transmissions with different transport blocks, the DCI indicates M time densities of PDSCH / PUSCH via the following alternatives. N is an integer greater than 1. M is an integer greater than 1 and M is not greater than N. Typically, M is equal to 2.

[0133] Alternative 1. With the first The reference signal transmitted together with the PDSCH / PUSCH transmission is transmitted at the first time density indicated by the DCI. The reference signal transmitted together with the two PDSCH / PUSCH transmissions is transmitted at the second time density indicated by the DCI, and so on.

[0134] Alternative 2. The reference signal transmitted together with the ((i mod M)+1)th PDSCH / PUSCH is transmitted at the ((i mod M)+1)th time density indicated by the DCI. i is the PDSCH / PUSCH index starting from 0. For example, if the DCI schedules 4 PDSCH transmissions and indicates 2 time densities, the time density of the reference signal transmitted together with the first PDSCH (i.e., the PDSCH with index 0) is the first time density indicated by the DCI. Similarly, the time density of the reference signal transmitted together with the third PDSCH (i.e., the PDSCH with index 2) is the first time density indicated by the DCI. The time density of the reference signal transmitted together with the second PDSCH (i.e., the PDSCH with index 1) is the second time density indicated by the DCI. The time density of the reference signal transmitted together with the fourth PDSCH (i.e., the PDSCH with index 3) is the second time density indicated by the DCI.

[0135] 7. Examples of different frequency densities of DMRS

[0136] Interference can be dynamic in the time domain. Figure 2 For example, the interference in slot 0 and slot 4 may be smaller than the interference in slot 1 / 2 / 3. Therefore, two DMRSs may be defined. The first DMRS has one frequency density and the second DMRS has another frequency density. The DCI indicates the frequency density of the DMRS used for the transmission of the scheduled data channel.

[0137] In summary, M groups of DMRS may be defined, and each group of DMRS has one frequency density. The DCI indicates one of the M groups of DMRS for the scheduled data channel. In other words, the DCI indicates one of the M frequency densities of DMRS for transmission of the scheduled data channel.

[0138] For example, in this embodiment, the base station does not need to configure or indicate any area. The base station only indicates the corresponding frequency density to the receiver.

[0139] 8. Example of Reference Signal Transmitted Overlapping with Guard Period

[0140] For a sub-band full-duplex system, one or more symbols are reserved for transmission in the communication direction. Fig.10 For example, in time slot 1, the third and fourth symbols are reserved as a guard period (GP) for switching from downlink to uplink. Similarly, in time slot 3, the eleventh and twelfth symbols are reserved as a guard period.

[0141] It should be noted that, in this article, the reference signal is not limited to a reference signal with different frequency densities, and it can be any reference signal.

[0142] The base station and the UE do not send any signal during the protection period. Therefore, in a sub-band full-duplex system, the DL symbol overlapping with the protection period and the UL symbol overlapping with the protection period can be used to transmit the reference signal. Since the base station and the UE do not send any signal during the protection period, the reference signal transmitted in the DL symbol (or UL symbol) overlapping with the protection period can be protected and less interfered.

[0143] The reference signal transmitted in the DL symbol overlapping with the guard period may be one of the following.

[0144] Alternative 1. DMRS: When a UE receives DMRS in a DL symbol overlapping with a guard period, no other UE performs uplink transmission.

[0145] Alternative 2: CSI-RS: When a UE or other base station receives DMRS in a DL symbol overlapping with a guard period, no other UE performs uplink transmission.

[0146] The reference signal transmitted in the UL symbol overlapping with the guard period may be one of the following.

[0147] Alternative 1. DMRS: When the base station receives DMRS in the UL symbol overlapping with the guard period, there is no interference from its own downlink.

[0148] Alternative 2. SRS: When the base station receives SRS in the UL symbol overlapping with the guard period, there is no interference from its own downlink.

[0149] The guard period can be configured as a flexible symbol, so the base station and the UE do not send any signal during the guard period.

[0150] Some preferred embodiments may combine the following solution features.

[0151] Referring to Sections 1 to 6, some example solutions implemented on the transmitter side are as follows.

[0152] 1. A wireless communication method (eg, Fig.11A The method 1100 depicted in ), comprising: sending (1102) from a first communication device to a second communication device an indication of N zones in a resource grid defined by transmission resources in the frequency domain and / or time resources in the time domain, wherein each of the N zones has a corresponding resource density indicating a time-frequency resource density configured for reference signal transmission, wherein N is an integer greater than 1; and transmitting (1104) a reference signal between the first communication device and the second communication device based on the density information. Reference Figures 2 to 10 Various configurations and examples of zones (also called "regions") are described.

[0153] Referring to Section 2, some example solutions can be as follows.

[0154] 2. The method according to solution 1 further includes: configuring frequency resources in the frequency domain for each of the N zones, wherein the frequency resources in the frequency domain are defined in units of resource blocks or resource block groups.

[0155] 3. The method according to solution 1, wherein the density information signals the value of N.

[0156] 4. A method according to solutions 2 to 3, wherein, in the absence of indication of time resources for a specific zone, the resource density is interpreted as applicable to all time units of the specific zone.

[0157] 5. A method according to solutions 2 to 3, wherein, in the absence of an indication of time resources for a specific zone, all time units transmitted by the first communication device or the second communication device are interpreted as all time units applicable to the specific zone.

[0158] 6. The method according to solutions 2 to 3 also includes: configuring time resources in the time domain for each of the N zones, wherein the time resources are defined for each zone in units of transmission symbols or time slots.

[0159] 7. The method according to any one of solutions 1 to 6, wherein the resource densities of the N zones are indicated using a scaling factor relative to the resource density of a reference zone.

[0160] 8. The method according to any one of solutions 1 to 7, wherein the resource density is indicated in a MAC CE.

[0161] 9. The method according to any one of solutions 1 to 8 further includes: transmitting a reference signal using transmission resources in one or more of the N zones, wherein, in each zone, the reference signal is transmitted using a density determined according to a rule.

[0162] 10. The method of solution 9, wherein the rule specifies the resource density per zone to be used for reference signals.

[0163] 11. The method according to any one of solutions 1 to 10 further includes: transmitting a reference signal by multiplexing with a data channel along a frequency domain and / or a time domain.

[0164] Referring to Section 3, some example solutions can be as follows.

[0165] 12. The method according to solution 1 includes: a first communication device sends an indication message to a second communication device to indicate resources used for data channel transmission and reference signal transmission, so that: when the data channel completely falls within a specific zone among N zones, the indication message indicates the resource density of reference signal transmission in the specific zone; or when the data channel occupies more than one zone among the N zones, the indication message indicates the resource density of the reference signal in the more than one zone; or when no reference signal is transmitted together with the data channel, the indication message indicates that no reference signal is transmitted.

[0166] 13. The method of solution 12, wherein upon determining that the estimated interference on the wireless channel between the first communication device and the second communication device is below a threshold, the indication message indicates that there is no reference signal transmission. The threshold may be a predefined number or may be implementation specific.

[0167] 14. The method according to solutions 12 to 13, wherein, in one zone, data channel transmission and reference signal transmission are configured such that resources allocated for reference channel transmission are not available for data channel transmission.

[0168] 15. The method according to solution 14, wherein the data channel transmission comprises PDSCH transmission or PUSCH transmission.

[0169] 16. The method according to solutions 12 to 15, wherein the indication message is carried in the DCI.

[0170] 17. The method according to solutions 12 to 16, wherein the indication indicates a configuration previously configured by a higher layer message.

[0171] 18. The method according to solution 17, wherein the high-layer message is an RRC message for configuring the N zones and / or the resource density of the N zones.

[0172] 19. The method of solution 12, wherein the indication message and the indication are transmitted in a DCI message.

[0173] Referring to Section 4, some example solutions can be as follows.

[0174] 20. The method according to solution 1, wherein the N zones are adjacent to the DMRS transmission in the time domain.

[0175] 21. The method according to solution 1, wherein the N zones are placed in the next symbol after the last DMRS symbol.

[0176] 22. The method according to solution 1, wherein the N zones are placed in a previous symbol adjacent to the first DMRS symbol.

[0177] Referring to Section 6, some example solutions can be as follows.

[0178] 23. The method according to solution 1, wherein the resource density corresponds to the density along the time domain.

[0179] 24. A method according to solution 23, wherein N zones are configured with different time densities of reference signals, the method further comprising: transmitting reference signals using transmission resources in one or more of the N zones, wherein, in each zone, the reference signals are transmitted using a density determined according to a rule.

[0180] 25. The method of solution 24, wherein the rule provides that, in case the reference signal uses transmission resources of a single zone among the N zones, the reference signal is transmitted using a time domain resource density associated with the single zone.

[0181] 26. A method according to solution 24, wherein the rule stipulates that, in the case where a reference signal uses transmission resources of multiple zones among N zones, when the reference signal is transmitted in each of the multiple zones, the reference signal is transmitted using a time domain resource density associated with the zone.

[0182] 27. A method according to solution 24, wherein the rule stipulates that, in the case where a reference signal uses transmission resources of multiple zones among N zones, the reference signal is transmitted using a time domain resource density corresponding to the time domain resource density of the first zone, and the first zone contains a first symbol for transmitting the reference signal.

[0183] 28. A method according to any one of solutions 23 to 27, wherein the time density is configured using an index, the index represents a different value in the RRC message and is indicated by a MAC CE or a DCI.

[0184] 29. The method of solution 28, wherein an index indicates that no reference signal transmission is performed.

[0185] 30. A method according to any one of solutions 1 to 29, wherein the reference signal comprises a pseudo-random sequence, a low peak-to-average power ratio sequence, or a sequence that is the same as a demodulation reference signal or a sounding reference signal or a channel state information reference signal.

[0186] 31. A method according to any of solutions 1 to 29, wherein the reference signal comprises a zero power transmission, wherein no signal is transmitted.

[0187] Referring to Sections 1 to 6, some example solutions implemented on the receiver side may be as follows.

[0188] 32. A wireless communication method (e.g., Fig. 11B The method 1150 described in , comprising: receiving (1152) an indication of N zones in a resource grid defined by transmission resources in the frequency domain and / or time resources in the time domain by a second communication device from a first communication device, wherein each of the N zones has a corresponding resource density indicating a time-frequency resource density configured for reference signal transmission, wherein N is an integer greater than 1; and transmitting (1154) a reference signal between the first communication device and the second communication device based on the density information. Reference Figures 2 to 10 Various configurations and examples of zones (also called "regions") are described.

[0189] Referring to Section 2, some example solutions can be as follows.

[0190] 33. The method according to solution 32, wherein for each of the N zones, frequency resources are configured in the frequency domain, wherein the frequency resources in the frequency domain are defined in units of resource blocks or resource block groups.

[0191] 34. The method of solution 32, wherein the density information signals the value of N.

[0192] 35. A method according to solutions 33 to 34, wherein, in the absence of indication of time resources for a specific zone, the resource density is interpreted as applicable to all time units of the specific zone.

[0193] 36. A method according to solutions 33 to 34, wherein, in the absence of an indication of time resources for a specific zone, all time units transmitted by the first communication device or the second communication device are interpreted as all time units applicable to the specific zone.

[0194] 37. A method according to solutions 33 to 34, wherein time resources in the time domain are configured for each of the N zones, wherein the time resources are defined for each zone in units of transmission symbols or time slots.

[0195] 38. A method according to any of solutions 32 to 37, wherein the resource densities of the N zones are indicated using a scaling factor relative to the resource density of a reference zone.

[0196] 39. The method according to any one of solutions 32 to 38, wherein the resource density is indicated in the MAC CE.

[0197] 40. The method according to any one of solutions 32 to 39 further includes: receiving a reference signal using transmission resources in one or more of the N zones, wherein, in each zone, the reference signal is transmitted using a density determined according to a rule.

[0198] 41. The method of solution 40, wherein the rules specify the resource density per zone to be used for reference signals.

[0199] 42. The method according to any one of solutions 32 to 41 further includes: receiving a reference signal by multiplexing with a data channel along a frequency domain and / or a time domain.

[0200] Referring to Section 3, some example solutions can be as follows.

[0201] 43. The method according to solution 32 includes: the second communication device receives an indication message from the first communication device to indicate the resources used for data channel transmission and reference signal transmission, so that: when the data channel completely falls within a specific zone among N zones, the indication message indicates the resource density of the reference signal transmission in the specific zone; or when the data channel occupies more than one zone among the N zones, the indication message indicates the resource density of the reference signal in the more than one zone; or when no reference signal is transmitted together with the data channel, the indication message indicates that no reference signal is transmitted.

[0202] 44. The method of solution 43, wherein upon determining that the estimated interference on the wireless channel between the first communication device and the second communication device is below a threshold, the indication message indicates that there is no reference signal transmission. The threshold may be a predefined number or may be implementation specific.

[0203] 45. The method according to solutions 43 to 44, wherein, in one zone, data channel transmission and reference signal transmission are configured such that resources allocated for reference channel transmission are not available for data channel transmission.

[0204] 46. ​​The method of solution 45, wherein the data channel transmission comprises a PDSCH transmission or a PUSCH transmission.

[0205] 47. A method according to solutions 43 to 46, wherein the indication message is carried in the DCI.

[0206] 48. A method according to solutions 43 to 47, wherein the indication indicates a configuration previously configured by a higher layer message.

[0207] 49. The method according to solution 48, wherein the high-layer message is an RRC message for configuring the N zones and / or the resource density of the N zones.

[0208] 50. The method of solution 43, wherein the indication message and the indication are transmitted in a DCI message.

[0209] Referring to Section 4, some example solutions can be as follows.

[0210] 51. The method of solution 32, wherein the N zones are adjacent to the DMRS transmission in the time domain.

[0211] 52. The method according to solution 32, wherein the N zones are placed in the next symbol after the last DMRS symbol.

[0212] 53. The method according to solution 32, wherein the N zones are placed in a previous symbol adjacent to the first DMRS symbol.

[0213] Referring to Section 6, some example solutions can be as follows.

[0214] 54. The method of solution 32, wherein the resource density corresponds to the density along the time domain.

[0215] 55. A method according to solution 54, wherein N zones are configured with different time densities of reference signals, the method further comprising: receiving reference signals using transmission resources in one or more of the N zones, wherein, in each zone, the reference signals are transmitted using a density determined according to a rule.

[0216] 56. The method of solution 55, wherein the rule provides that, in case the reference signal uses transmission resources of a single zone among the N zones, the reference signal is transmitted using a time domain resource density associated with the single zone.

[0217] 57. A method according to solution 55, wherein the rule stipulates that, in the case where a reference signal uses transmission resources of multiple zones among N zones, when the reference signal is transmitted in each of the multiple zones, the reference signal is transmitted using a time domain resource density associated with the zone.

[0218] 58. A method according to solution 55, wherein the rule stipulates that, in the case where a reference signal uses transmission resources of multiple zones among N zones, the reference signal is transmitted using a time domain resource density corresponding to the time domain resource density of the first zone, and the first zone contains a first symbol for transmitting the reference signal.

[0219] 59. A method according to any one of solutions 54 to 58, wherein the time density is configured using an index, the index represents a different value in the RRC message and is indicated by a MAC CE or a DCI.

[0220] 60. The method of solution 59, wherein an index indicates that no reference signal transmission is performed.

[0221] 61. A method according to any one of solutions 32 to 60, wherein the reference signal comprises a pseudo-random sequence, a low peak-to-average power ratio sequence, or a sequence that is the same as a demodulation reference signal or a sounding reference signal or a channel state information reference signal.

[0222] 62. The method of any of solutions 32 to 60, wherein the reference signal comprises a zero power transmission, wherein no signal is transmitted.

[0223] The above solution can be preferably implemented as follows:

[0224] 63. A method according to any one of solutions 1 to 62, wherein the first communication device corresponds to a base station and the second communication device corresponds to a user equipment.

[0225] 64. A method according to any one of solutions 1 to 62, wherein the first communication device corresponds to a user equipment and the second communication device corresponds to a base station.

[0226] 65. A wireless communication device comprising a processor configured to perform a method according to any one of solutions 1 to 64.

[0227] 66. A computer-readable medium storing a processor-executable code which, when executed by a processor, causes the processor to perform a method according to any one of solutions 1 to 64.

[0228] Fig.12 is a block diagram of an example implementation of a wireless communication device 1200. Methods 1100 and 1150 may be performed by the device 1200. In some embodiments, for example, when performing the method 1100, the device 1200 may be a first communication device, such as a base station or network device of a wireless network, and the second communication device may be a UE. In some embodiments, for example, when performing the method 1150, the device 1200 may be a second communication device, such as a UE. The device 1200 includes one or more processors (e.g., processor electronics 1210), transceiver circuits 1215, and one or more antennas 1220 for sending and receiving wireless signals. The device 1200 may include a memory 1205, which may be used to store data and instructions for use by the processor electronics 1210. The device 1200 may also include additional network interfaces to additional equipment of one or more core networks or network operators. Fig.12 This additional network interface, not explicitly shown in the figure, may be a wired interface (eg, fiber optic or Ethernet) or a wireless interface.

[0229] Fig.13 An example of a wireless communication system 1300 is depicted in which the various techniques described herein may be implemented. The system 1300 includes a base station 1302 that may be communicatively coupled to a core network (1312) and a wireless communication medium 1304 to communicate with one or more user devices 1306. The user device 1306 may be a smartphone, a tablet, a machine-to-machine communication device, an Internet of Things (IoT) device, or the like.

[0230] It should be understood that techniques for achieving different reference signal resource densities in the time domain and / or frequency domain are implemented. In one advantageous aspect, a transmitter (e.g., a base station) can use the disclosed techniques to schedule denser reference signal resource grids in time-frequency zones where interference potential is greater (e.g., time-frequency zones where uplink and downlink transmissions occupy adjacent or close time slots of subcarriers). Those skilled in the art will also appreciate that the disclosed techniques can be used to reserve certain resource elements as zero-power transmission resources (e.g., reference signal transmissions that do not include signal transmissions). In addition, embodiments can divide all available time-frequency resources into multiple zones (also referred to as regions in this document), and resource density can be specified by zone. Data and reference signal transmissions can fall entirely within a single zone, or can occupy multiple zones, thereby providing a flexible resource density organization.

[0231] The disclosed and other embodiments, modules and functional operations described in this document may be implemented in digital electronic circuits, or in computer software, firmware or hardware (including the structures disclosed in this document and their structural equivalents), or in a combination of one or more of them. The disclosed and other embodiments may be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded in a computer-readable medium, for execution by a data processing device or for controlling the operation of the data processing device. The computer-readable medium may be a machine-readable storage device, a machine-readable storage substrate, a storage device, a combination of substances that implement a machine-readable propagation signal, or a combination of one or more of them. The term "data processing device" includes all devices, equipment and machines for processing data, including, for example, a programmable processor, a computer or multiple processors or computers. In addition to hardware, the device may include code that creates an execution environment for the computer program in question, for example, code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagation signal is an artificially generated signal, such as a machine-generated electrical, optical or electromagnetic signal, which is generated to encode information for transmission to a suitable receiver device.

[0232] A computer program (also referred to as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that stores other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple collaborative files (e.g., files storing one or more modules, subroutines, or code portions). A computer program can be deployed to execute on one or more computers, which can be located in one location, or distributed in multiple locations and interconnected by a communication network.

[0233] The processes and logic flows described in this document may be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by special purpose logic circuits, and the apparatus may also be implemented as special purpose logic circuits, such as Field Programmable Gate Arrays (FPGAs) or Application Specific Integrated Circuits (ASICs).

[0234] For example, processors suitable for executing computer programs include general-purpose microprocessors and special-purpose microprocessors, as well as any one or more processors of any kind of digital computer. Typically, the processor will receive instructions and data from a read-only memory or a random access memory or both. The basic elements of a computer are a processor for executing instructions and one or more storage devices for storing instructions and data. Typically, a computer will also include or be operably coupled to one or more large-capacity storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, to receive data from the one or more large-capacity storage devices, or to send data to them, or to send and receive. However, a computer does not need to have such a device. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and storage devices, including, for example, semiconductor storage devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD ROM and DVD-ROM disks. The processor and memory can be supplemented or incorporated into them by dedicated logic circuits.

[0235] Although this document contains many details, these details should not be interpreted as limitations on the scope of the claimed invention or the scope that may be claimed, but should be understood as descriptions of features that are peculiar to a particular embodiment. Certain features described in the context of a separate embodiment in this document may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination. In addition, although the above-mentioned features may be described as working in certain combinations, and even initially claimed as such, one or more features from the claimed combination may be deleted from the combination in some cases, and the claimed combination may be for a sub-combination or a variation of the sub-combination. Similarly, although the operations are described in a particular order in the accompanying drawings, this should not be understood as requiring the operations to be performed in the particular order or continuous order shown, or requiring the execution of all the operations shown to obtain the desired results.

[0236] Only a few examples and implementations are disclosed. Changes, modifications, and enhancements may be made to the described examples and implementations, as well as other implementations, based on what is disclosed.

Claims

1. A wireless communication method, comprising: sending, from the first communication device to the second communication device, an indication of N zones in a resource grid defined by transmission resources in the frequency domain and / or time resources in the time domain, wherein each of the N zones has a corresponding resource density indicating a time-frequency resource density configured for reference signal transmission, Wherein, N is an integer greater than 1; and The reference signal is transmitted between the first communication device and the second communication device according to density information.

2. The method according to claim 1, further comprising: Frequency resources in the frequency domain are configured for each of the N zones, wherein the frequency resources in the frequency domain are defined in units of resource blocks or resource block groups.

3. The method according to claim 1, wherein: The density information signals the value of N.

4. The method according to claims 2 to 3, wherein: In case the time resources are not indicated for a specific zone, the resource density is interpreted as being applicable to all time units of the specific zone.

5. The method according to claims 2 to 3, wherein: In the case where no time resources are indicated for a specific zone, all time units transmitted by the first communication device or the second communication device are interpreted as all time units applicable to the specific zone.

6. The method according to claims 2 to 3, further comprising: A time resource in the time domain is configured for each of the N zones, wherein the time resource is defined for each zone in units of transmission symbols or time slots.

7. The method according to any one of claims 1 to 6, wherein: The resource densities of the N zones are indicated using a scaling factor relative to the resource density of a reference zone.

8. The method according to any one of claims 1 to 7, wherein: The resource density is indicated in a medium access control MAC control element CE.

9. The method according to any one of claims 1 to 8, further comprising: A reference signal is transmitted using transmission resources in one or more of the N zones, wherein in each zone, the reference signal is transmitted using a density determined according to a rule.

10. The method according to claim 9, wherein: The rule specifies a resource density per zone to be used for the reference signal.

11. The method according to any one of claims 1 to 10, further comprising: The reference signal is transmitted by multiplexing with the data channel along the frequency domain and / or the time domain.

12. The method according to claim 1, comprising: The first communications device sends an indication message to the second communications device to indicate resources used for data channel transmission and reference signal transmission, so that: In a case where the data channel completely falls within a specific zone among the N zones, the indication message indicates a resource density of the reference signal transmission in the specific zone; or In a case where the data channel occupies more than one of the N zones, the indication message indicates resource density of the reference signal of the more than one zone; or In a case where no reference signal is transmitted together with the data channel, the indication message indicates that no reference signal is transmitted.

13. The method according to claim 12, wherein: When it is determined that the estimated interference on the wireless channel between the first communication device and the second communication device is lower than a threshold, the indication message indicates no reference signal transmission.

14. The method according to claims 12 to 13, wherein: In one zone, the data channel transmission and reference signal transmission are configured such that resources allocated to the reference channel transmission are not available for the data channel transmission.

15. The method according to claim 14, wherein: The data channel transmission includes physical downlink shared channel PDSCH transmission or physical uplink shared channel PUSCH transmission.

16. The method according to claims 12 to 15, wherein: The indication message is carried in downlink control information DCI.

17. The method according to claims 12 to 16, wherein: The indication indicates a configuration previously configured by a higher layer message.

18. The method according to claim 17, wherein: The high-layer message is a radio resource control RRC message for configuring the N zones and / or the resource density of the N zones.

19. The method according to claim 12, wherein: The indication message and the indication are transmitted in a DCI message.

20. The method according to claim 1, wherein: The N zones are adjacent to the DMRS transmission in the time domain.

21. The method according to claim 1, wherein: The N zones are placed in the next symbol after the last DMRS symbol.

22. The method according to claim 1, wherein: The N zones are placed in a previous symbol adjacent to the first DMRS symbol.

23. The method according to claim 1, wherein: The resource density corresponds to a density along the time domain.

24. The method according to claim 23, wherein: The N zones are configured with different time densities of reference signals, and the method further comprises: A reference signal is transmitted using transmission resources in one or more of the N zones, wherein in each zone, the reference signal is transmitted using a density determined according to a rule.

25. The method according to claim 24, wherein: The rule stipulates that, if the reference signal uses transmission resources of a single zone among the N zones, the reference signal is transmitted using a time domain resource density associated with the single zone.

26. The method according to claim 24, wherein: The rule stipulates that, if the reference signal uses transmission resources of multiple zones among the N zones, when the reference signal is transmitted in each zone among the multiple zones, the reference signal is transmitted using a time domain resource density associated with the zone.

27. The method according to claim 24, wherein: The rule stipulates that, when the reference signal uses transmission resources of multiple zones among the N zones, the reference signal is transmitted using a time domain resource density corresponding to a time domain resource density of a first zone, the first zone including a first symbol for transmitting the reference signal.

28. The method according to any one of claims 23 to 27, wherein: The time density is configured using an index, which represents a different value in an RRC message and is indicated by a MAC CE or a DCI.

29. The method according to claim 28, wherein: An index indicates that reference signal transmission is not performed.

30. The method according to any one of claims 1 to 29, wherein: The reference signal includes a pseudo-random sequence, a low peak-to-average power ratio sequence, or a sequence that is the same as a demodulation reference signal, a sounding reference signal, or a channel state information reference signal.

31. The method according to any one of claims 1 to 29, wherein: The reference signal comprises a zero power transmission, wherein no signal is transmitted.

32. A wireless communication method, comprising: The second communication device receives from the first communication device an indication of N zones in a resource grid defined by transmission resources in the frequency domain and / or time resources in the time domain, wherein each of the N zones has a corresponding resource density indicating a time-frequency resource density configured for reference signal transmission, Wherein, N is an integer greater than 1; and The reference signal is transmitted between the first communication device and the second communication device according to density information.

33. The method of claim 32, wherein: Frequency resources in the frequency domain are configured for each of the N zones, wherein the frequency resources in the frequency domain are defined in units of resource blocks or resource block groups.

34. The method of claim 32, wherein: The density information signals the value of N.

35. The method according to claims 33 to 34, wherein: In case the time resources are not indicated for a specific zone, the resource density is interpreted as being applicable to all time units of the specific zone.

36. The method according to claims 33 to 34, wherein: In the case where no time resources are indicated for a specific zone, all time units transmitted by the first communication device or the second communication device are interpreted as all time units applicable to the specific zone.

37. The method according to claims 33 to 34, wherein: A time resource is configured in the time domain for each of the N zones, wherein the time resource is defined for each zone in units of transmission symbols or time slots.

38. The method according to any one of claims 32 to 37, wherein: The resource densities of the N zones are indicated using a scaling factor relative to the resource density of a reference zone.

39. The method according to any one of claims 32 to 38, wherein: The resource density is indicated in the MAC CE.

40. The method according to any one of claims 32 to 39, further comprising: A reference signal is received using transmission resources in one or more of the N zones, wherein in each zone, the reference signal is transmitted using a density determined according to a rule.

41. The method of claim 40, wherein: The rule specifies a resource density per zone to be used for the reference signal.

42. The method according to any one of claims 32 to 41, further comprising: The reference signal is received by multiplexing with the data channel along the frequency domain and / or the time domain.

43. The method of claim 32, comprising: The second communication device receives an indication message from the first communication device to indicate resources used for data channel transmission and reference signal transmission, so that: In a case where the data channel completely falls within a specific zone among the N zones, the indication message indicates a resource density of the reference signal transmission in the specific zone; or In a case where the data channel occupies more than one of the N zones, the indication message indicates resource density of the reference signal of the more than one zone; or In a case where no reference signal is transmitted together with the data channel, the indication message indicates that no reference signal is transmitted.

44. The method of claim 43, wherein: When it is determined that the estimated interference on the wireless channel between the first communication device and the second communication device is below a threshold, the indication message indicates that there is no reference signal transmission.

45. The method according to claims 43 to 44, wherein: In one zone, the data channel transmission and reference signal transmission are configured such that resources allocated to the reference channel transmission are not available for the data channel transmission.

46. ​​The method of claim 45, wherein: The data channel transmission includes physical downlink shared channel PDSCH transmission or physical uplink shared channel PUSCH transmission.

47. The method according to claims 43 to 46, wherein: The indication message is carried in downlink control information DCI.

48. The method of claims 43 to 47, wherein: The indication indicates a configuration previously configured by a higher layer message.

49. The method of claim 48, wherein: The high-layer message is a radio resource control RRC message for configuring the N zones and / or the resource density of the N zones.

50. The method of claim 43, wherein: The indication message and the indication are transmitted in a DCI message.

51. The method of claim 32, wherein: The N zones are adjacent to the DMRS transmission in the time domain.

52. The method of claim 32, wherein: The N zones are placed in the next symbol after the last DMRS symbol.

53. The method of claim 32, wherein: The N zones are placed in a previous symbol adjacent to the first DMRS symbol.

54. The method of claim 32, wherein: The resource density corresponds to a density along the time domain.

55. The method of claim 54, wherein: The N zones are configured with different time densities of reference signals, and the method further comprises: A reference signal is received using transmission resources in one or more of the N zones, wherein in each zone, the reference signal is transmitted using a density determined according to a rule.

56. The method of claim 55, wherein: The rule stipulates that, if the reference signal uses transmission resources of a single zone among the N zones, the reference signal is transmitted using a time domain resource density associated with the single zone.

57. The method of claim 55, wherein: The rule stipulates that, if the reference signal uses transmission resources of multiple zones among the N zones, when the reference signal is transmitted in each zone among the multiple zones, the reference signal is transmitted using a time domain resource density associated with the zone.

58. The method of claim 55, wherein: The rule stipulates that, when the reference signal uses transmission resources of multiple zones among the N zones, the reference signal is transmitted using a time domain resource density corresponding to a time domain resource density of a first zone, the first zone including a first symbol for transmitting the reference signal.

59. The method according to any one of claims 54 to 58, wherein: The time density is configured using an index, which represents a different value in an RRC message and is indicated by a MAC CE or a DCI.

60. The method of claim 59, wherein: An index indicates that reference signal transmission is not performed.

61. The method according to any one of claims 32 to 60, wherein: The reference signal includes a pseudo-random sequence, a low peak-to-average power ratio sequence, or a sequence that is the same as a demodulation reference signal, a sounding reference signal, or a channel state information reference signal.

62. The method of any one of claims 32 to 60, wherein: The reference signal comprises a zero power transmission, wherein no signal is transmitted.

63. The method according to any one of claims 1 to 62, wherein: The first communication device corresponds to a base station, and the second communication device corresponds to a user equipment.

64. The method according to any one of claims 1 to 62, wherein: The first communication device corresponds to a user equipment, and the second communication device corresponds to a base station.

65. A wireless communication device comprising a processor configured to perform the method according to any one of claims 1 to 64.

66. A computer readable medium storing processor executable code, which, when executed by the processor, causes the processor to perform the method according to any one of claims 1 to 64.

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