CN108737306B

CN108737306B - Frequency division multiplexing based communication

Info

Publication number: CN108737306B
Application number: CN201710245002.0A
Authority: CN
Inventors: 汪勇刚
Original assignee: Nokia Shanghai Bell Co Ltd
Current assignee: Nokia Shanghai Bell Co Ltd
Priority date: 2017-04-14
Filing date: 2017-04-14
Publication date: 2020-12-11
Anticipated expiration: 2037-04-14
Also published as: CN108737306A

Abstract

Implementations of the present disclosure provide a scheme for frequency division multiplexing-based communication. According to a method implemented at a communication device, a first interference expected to be caused by a first signal at a receiving end of a second signal and a second interference expected to be caused by the second signal at the receiving end of the first signal in a simultaneous transmission of the first signal and the second signal are determined. The first signal will be transmitted on a first subcarrier having a first frequency spacing and the second signal will be transmitted on a second subcarrier having a second frequency spacing. The second subcarrier is adjacent to the first subcarrier and the second frequency spacing is different from the first frequency spacing. The method also includes generating a first transmission signal by removing the second interference from the first signal, and generating a second transmission signal by removing the first interference from the second signal. The method also includes multiplexing the first transmission signal and the second transmission signal for simultaneous transmission.

Description

Frequency division multiplexing based communication

Technical Field

Implementations of the present disclosure relate generally to communication technology and, more particularly, to frequency division multiplexing based communication.

Background

In a conventional communication system, a transmitting end may employ various multiplexing techniques such as Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), etc. in order to improve transmission efficiency when communicating with a plurality of receiving ends. Generally, in the same communication system, the entire system bandwidth is divided into a plurality of subcarriers at the same frequency interval. In communication, signals destined for different receiving ends may be transmitted on the divided one or more subcarriers.

In recent communication developments, New Radio (NR) access technologies are being researched, which aim to provide a wider range of vertical communication services such as Machine Type Communication (MTC), large-scale MTC (MTC), enhanced mobile broadband (eMBB) communication, ultra-reliable low-delay communication (URLLC), and the like, in a single technology framework. It has been proposed to employ scalable frequency spacing in new communication systems. Scalable frequency spacing refers to the division of subcarriers at different frequency intervals for different receiving ends and/or services. Thus, in the same system, a portion of the overall system bandwidth is divided into subcarriers having a first frequency spacing, while another portion may be divided into subcarriers having a different second frequency spacing.

TDM and FDM can still be used for multiplexing of multiple transmissions in a system with scalable frequency spacing of subcarriers. In TDM-based multiplexing, transmissions utilizing different frequency intervals may be assigned to different time slots. In FDM based multiplexing, different transmissions are transmitted simultaneously on subcarriers having different frequency spacing. However, TDM based multiplexing may not guarantee the quality of service requirements of all traffic, especially in terms of latency. FDM based multiplexing can support services with different latency requirements and can also have a high degree of flexibility for supporting services with different traffic models, different packet sizes and bandwidth requirements. Also, NR based systems will be allocated a wider system bandwidth, so multiplexing techniques employing FDM are also beneficial.

FDM based multiplexing introduces interference problems in the presence of subcarriers of different frequency spacing on the system band, since only subcarriers with the same frequency spacing are orthogonal to each other. Therefore, there is a need for an interference solution that addresses FDM-based communication in the case of multiple frequency intervals.

Disclosure of Invention

In accordance with an example implementation of the present disclosure, a scheme for frequency division multiplexing based communication is provided.

In a first aspect of the disclosure, a method implemented at a communication device is provided. The method includes determining a first interference expected to be caused by the first signal at a receiving end of the second signal and a second interference expected to be caused by the second signal at the receiving end of the first signal in a simultaneous transmission of the first signal and the second signal. The first signal will be transmitted on a first subcarrier having a first frequency spacing and the second signal will be transmitted on a second subcarrier having a second frequency spacing. The second subcarrier is adjacent to the first subcarrier and the second frequency spacing is different from the first frequency spacing. The method also includes generating a first transmission signal by removing the second interference from the first signal, and generating a second transmission signal by removing the first interference from the second signal. The method also includes multiplexing the first transmission signal and the second transmission signal for simultaneous transmission.

In a second aspect of the disclosure, a method implemented at a communication device is provided. The method includes receiving a first received signal on a first subcarrier having a first frequency spacing. The first received signal is associated with a first signal transmitted by a transmitting device. The first signal is transmitted simultaneously with a second signal on a second subcarrier having a second frequency spacing, the second subcarrier being adjacent to the first subcarrier, and the second frequency spacing being different from the first frequency spacing. The first received signal contains interference that has been caused by the second signal and a transmission signal generated by the transmitting device removing the interference from the first signal. The method includes processing a first received signal to obtain a first signal without removing interference.

In a third aspect of the disclosure, a communication device is provided. The communication device includes a processor; and a memory coupled with the processor, the memory having instructions stored therein that, when executed by the processor, cause the transmitting device to perform actions. The actions include determining a first interference expected to be caused by the first signal at a receiving end of the second signal and a second interference expected to be caused by the second signal at the receiving end of the first signal in a simultaneous transmission of the first signal and the second signal. The first signal will be transmitted on a first subcarrier having a first frequency spacing and the second signal will be transmitted on a second subcarrier having a second frequency spacing. The second subcarrier is adjacent to the first subcarrier and the second frequency spacing is different from the first frequency spacing. The actions also include generating a first transmission signal by removing the second interference from the first signal, and generating a second transmission signal by removing the first interference from the second signal. The actions also include multiplexing the first transmission signal and the second transmission signal for simultaneous transmission.

In a fourth aspect of the disclosure, a communication device is provided. The communication device includes a processor; and a memory coupled with the processor, the memory having instructions stored therein that, when executed by the processor, cause the transmitting device to perform actions. The actions include receiving a first received signal on a first subcarrier having a first frequency spacing. The first received signal is associated with a first signal transmitted by a transmitting device. The first signal is transmitted simultaneously with a second signal on a second subcarrier having a second frequency spacing, the second subcarrier being adjacent to the first subcarrier, and the second frequency spacing being different from the first frequency spacing. The first received signal contains interference that has been caused by the second signal and a transmission signal generated by the transmitting device removing the interference from the first signal. The actions include processing a first received signal to obtain a first signal without removing interference.

In a fifth aspect of the disclosure, a computer-readable medium is provided. The computer-readable medium has stored thereon computer-executable instructions. The computer-executable instructions, when executed by one or more processors, cause the one or more processors to perform the steps of the method according to the first aspect.

In a sixth aspect of the disclosure, a computer-readable medium is provided. The computer-readable medium has stored thereon computer-executable instructions. The computer-executable instructions, when executed by one or more processors, cause the one or more processors to perform the steps of the method according to the second aspect.

It should be understood that what is described in this summary section is not intended to limit key or critical features of the disclosure, nor is it intended to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

The above and other features, advantages and aspects of various implementations of the present disclosure will become more apparent by referring to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, like or similar reference characters designate like or similar elements, and wherein:

FIG. 1 is a schematic diagram of an example network environment in which implementations described in this disclosure may be implemented;

fig. 2A shows a schematic diagram of subcarriers with different frequency spacing in the frequency domain;

fig. 2B shows the distribution of signals transmitted on subcarriers having different frequency intervals in the time and frequency domains;

fig. 3A and 3B are diagrams illustrating interference between adjacent subcarriers having different frequency intervals;

fig. 4 illustrates a schematic block diagram of a system for frequency division multiplexing-based communication in accordance with some implementations of the present disclosure;

fig. 5 illustrates a schematic block diagram of an encoder in a communication device in accordance with some implementations of the present disclosure;

fig. 6 is a flow diagram of a process for frequency division multiplexing-based communication in accordance with some implementations of the present disclosure;

fig. 7 is a flow diagram of a process for frequency division multiplexing-based communication according to further implementations of the present disclosure;

FIG. 8 illustrates a block diagram of an apparatus in accordance with some implementations of the present disclosure;

FIG. 9 illustrates a block diagram of an apparatus according to further implementations of the present disclosure; and

fig. 10 shows a simplified block diagram of a device suitable for implementing an implementation of the present disclosure.

Throughout the drawings, the same or similar reference numbers refer to the same or similar elements.

Detailed description of the invention

Implementations of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain implementations of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the implementations set forth herein, but rather are provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and implementations of the present disclosure are for illustration purposes only and are not intended to limit the scope of the present disclosure.

In the description of implementations of the present disclosure, the terms "include" and "comprise," and similar terms, are to be understood as being open-ended, i.e., "including but not limited to. The term "based on" should be understood as "based at least in part on". The term "one implementation" or "the implementation" should be understood as "at least one implementation". The terms "first," "second," and the like may refer to different or the same object. Other explicit and implicit definitions are also possible below.

The term "terminal equipment" or "user equipment" (UE) as used herein refers to any terminal equipment capable of wireless communication with a base station or with each other. As an example, the terminal device may include a Mobile Terminal (MT), a Subscriber Station (SS), a Portable Subscriber Station (PSS), a Mobile Station (MS), or an Access Terminal (AT), and the above-described devices in a vehicle. The terminal device may be any type of mobile terminal, fixed terminal, or portable terminal including a mobile handset, station, unit, device, multimedia computer, multimedia tablet, internet node, communicator, desktop computer, laptop computer, notebook computer, netbook computer, tablet computer, Personal Communication System (PCS) device, personal navigation device, Personal Digital Assistant (PDA), audio/video player, digital camera/camcorder, positioning device, television receiver, radio broadcast receiver, electronic book device, game device, smart meter, or other device that may be used for communication, or any combination of the above. In the context of the present disclosure, the terms "terminal device" and "user equipment" may be used interchangeably for purposes of discussion convenience.

The term "network device" as used herein refers to a base station or other entity or node having a particular function in a communication network. A "base station" (BS) may represent a node B (NodeB or NB), an evolved node B (eNodeB or eNB), a Remote Radio Unit (RRU), a Radio Head (RH), a Remote Radio Head (RRH), a relay, or a low power node such as a pico base station, a femto base station, or the like. The coverage area of a base station, i.e. the geographical area where it is able to provide service, is called a cell. In the context of the present disclosure, the terms "network device" and "base station" may be used interchangeably for purposes of discussion convenience, and may primarily be referred to as an eNB as an example of a network device. Both "network device" and "terminal device" may be referred to herein as communication devices.

In a communication system, one communication device may transmit information to a plurality of other communication devices or to transmit different information. FIG. 1 depicts a network environment 100 in which implementations of the present disclosure may be implemented. In this environment 100, a plurality of terminal devices 120-1 through 120-3 are in a serving cell 112 of a network device 110 and are served by the network device 110. Although three terminal devices in the form of mobile phones are shown in fig. 1, network device 110 may serve more or fewer terminal devices, and the types of terminal devices served may be the same or different (e.g., other types of terminal devices are also possible). Hereinafter, terminal devices 120-1 through 120-3 are collectively referred to as terminal devices 120 or individually represented as terminal devices 120.

The network device 110 and the terminal device 120 may communicate with each other to transmit various service data, control information, and the like. The transmitting end may be network device 110 and the receiving end may be one or more terminal devices 120, and such transmissions may be referred to as Downlink (DL) transmissions. In other cases, the transmitting end may be terminal device 120 and the receiving end may be network device 110, and such transmissions may be referred to as Uplink (UL) transmissions. Further, one terminal device 120 may transmit information to one or more terminal devices 120, which is referred to as a device-to-device (D2D) transmission. Of course, although not shown, the network device 110 may also communicate with other network devices via a backhaul (backhaul) interface or the like.

Communications in network environment 100 may be implemented in accordance with any suitable communication protocol, including, but not limited to, first-generation (1G), second-generation (2G), third-generation (3G), fourth-generation (4G), and fifth-generation (5G) cellular communication protocols, wireless local area network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE)802.11, and/or any other protocol now known or later developed.

As mentioned above, in one communication system, there may be a plurality of different subcarrier spacing configurations for different receiving ends or different traffic, each subcarrier spacing configuration being associated with one frequency interval. Thus, a portion of the overall system bandwidth of the same system may be divided into subcarriers having a first frequency spacing, while another portion may be divided into subcarriers having a different second frequency spacing. For example, the frequency interval of the subcarriers (denoted as f _ sc) may be calculated as follows (such equation is calculated in english)Also known as numerology) to give: f _ sc-15 × 2ⁿkHz, where n may take different non-negative integers for different receivers and/or services, resulting in corresponding different frequency intervals f _ sc. In this example, the baseline of the frequency interval is 15kHz and the ratio between different frequency intervals may be 2ⁿ. In other examples, the different frequency intervals may also be based on a particular scaling factor (e.g., scaling factor N-2)ⁿ) To be determined. For example, the basic frequency may be separated by 15kHz and a scaling factor N-2ⁿTo obtain frequency intervals of 3.75kHz, 7.5kHz, 30kHz, 60kHz, etc.

For example, in the example of fig. 2A, a transmission to a first receiver a may be allocated a frequency segment (F1-F2) 210 of the full system bandwidth with a first frequency interval of F sc1 per subcarrier, while a transmission to a second receiver B may be allocated a frequency segment (F2-F3) 220 of the full bandwidth with a second frequency interval of F sc2 per subcarrier. The frequency interval f _ sc2 is different from f _ sc1, e.g., f _ sc2 is greater than f _ sc 1. It should be understood that the number of sub-carriers allocated to different receiving ends may be one or more.

In a system having different frequency intervals, a transmitting end may employ both Time Division Multiplexing (TDM) and Frequency Division Multiplexing (FDM) in order to multiplex transmissions based on the different frequency intervals. FDM is more readily employed in such systems due to its advantages in terms of latency and flexibility, etc., and in view of the future use of wider bandwidths (e.g., in systems based on new radio access technologies). However, since different subcarriers may have different frequency intervals, it is not ensured that the subcarriers are orthogonal to each other, thereby causing interference between interfering adjacent subcarriers. Such interference may be referred to as multi-subcarrier inter-interval interference, as interference is due to different determination criteria for the frequency spacing of the subcarriers.

Fig. 2B shows the distribution of the first signal 212 and the second signal 222 in the time domain and the frequency domain when these signals are transmitted to the first receiving end and the second receiving end, respectively, on subcarriers of the

frequency bins

220 and 210 of fig. 2A. In this example, the first frequency interval f _ sc1 is twice the second frequency interval f _ sc 2. Thus, in the time domain, two symbols a1 and a2 of the signal 212 may be transmitted and one symbol B of the signal 212 may be transmitted within the same time. In frequency division multiplexing, symbols a1 and a2 of the first signal 212 and symbol B of the second signal 222 may be transmitted concurrently by a transmitting end to first and second receiving ends, e.g., transmitted in the same transmission slot.

Due to the different frequency intervals, after performing a time-domain to frequency-domain transform at the receiving end with parameters corresponding to a certain frequency interval (e.g., using corresponding fourier transform points in a fourier transform), a sub-carrier near frequency F2 transmitting the first signal 212 will interfere with a sub-carrier near frequency F2 transmitting the second signal 222, and thus the frequency spectrum of the corresponding signal will be observed to be spread out of band at the receiving end. For example, as shown in fig. 3A, at the second receiving end, after performing a time-domain to frequency-domain transform, a received signal 320 (denoted as R) at the first receiving end is observed_A) Is leaked to the second receiver end, thereby resulting in a transmission signal 310 (denoted as T) intended to be received by the second receiver end_B) Interference 322 (denoted as I)_A) Resulting in distortion of the received signal at the second receiving end. Similarly, as shown in fig. 3B, after performing the time-domain to frequency-domain transformation, a received signal 330 (denoted as R) of the second receiving end can also be observed at the first receiving end_B) Is leaked to the first receiving end, resulting in a signal 340 (denoted T) being received in anticipation of_A) Interference 332 (denoted as I)_B)。

From the above analysis, it can be seen that FDM-based communication needs to address the problem of interference. In conventional communication systems capable of resolving interference, there are two options. One approach is the use of guard bands (guard bands) similar to those used by the narrowband internet of things (NB-IoT) in current Long Term Evolution (LTE). Guard bands may be inserted between subcarriers having different frequency spacing, for example, before

frequency bins

210 and 220 of fig. 2A, to reduce interference with each other and/or to mitigate the degree of limitation on the desired spectrum. For effective interference suppression, the size of the guard band between subcarriers depends on many factors, such as the calculation parameters of the frequency spacing, the received power difference of the signals carried on the subcarriers of different frequency spacing, the total bandwidth used by the different subcarrier spacing configurations, and the communication performance requirements. Typically, the spectrum resources reserved for guard bands are around 6 x 15kHz, such as in current LTE NB IoT systems. Excessive guard bands between different subcarrier spacing configurations will greatly reduce spectrum utilization.

Another solution is to suppress the interference by windowing and filtering. To reduce interference, the transmit spectrum for each subcarrier frequency spacing configuration may be limited, e.g., requiring better spectrum roll-off. Windowing and filtering are means by which the spectral roll-off characteristics of the transmitting and receiving ends can be improved. However, this would require that the computational magnitude of the time-domain filtering in the receiving end be significantly higher than the time-frequency or frequency-time transform for each subcarrier frequency spacing configuration. This will increase the system complexity. Second, both windowing and filtering will cause signal distortion on the shoulders of the frequency bins at different receiving ends, which is more pronounced when higher order modulation, such as Quadrature Amplitude Modulation (QAM) of order 64, 128, 256 or more, is used.

Accordingly, improved solutions for addressing interference problems in FDM-based systems with multiple subcarrier spacings are desired. Implementations of the present disclosure provide a solution to some of the above or other potential problems. In this scheme, a communication device at a transmitting end estimates interference that two or more signals to be transmitted will cause at a receiving end of other signals, and removes interference caused by the other signals from each signal. The interference-removed signals are multiplexed and then transmitted simultaneously. Since the communication device at the transmitting end has estimated and removed the mutual interference between the signals from the signals, the communication device at the receiving end may not need to perform the estimation and removal of the mutual interference between the signals after receiving the signals. The communication device at the receiving end can directly determine the received signal as the desired signal without considering other interference. Of course, in other implementations, the receiving end may perform other conventional processing on the received signal, such as estimating and removing channel interference.

It can be seen that according to the technical solution of the present disclosure, the interference is estimated and removed in advance by the device at the transmitting end. Such a concept is theoretically called dirty paper coding (dirty paper coding). Dirty paper coding involves the following scenarios: how to continue writing information on a piece of paper (at the transmitting end) and make it readable without knowing the color and position of the ink (at the receiving end) is achieved if a lot of content has been written on the piece of paper or if there are a lot of stains (interference information is known at the transmitting end), i.e. dirty paper. According to the dirty paper coding, in the technical scheme of the present disclosure, since the communication device at the transmitting end can know all information of the original signals, it is possible to estimate the inter-signal interference of adjacent subcarriers at the receiving end due to different frequency intervals from the signals. By removing these interferences in advance, the communication device at the receiving end will not need to continue to handle this part of the interference.

By the technical scheme of the disclosure, the problem of interference in the FDM-based system with multiple frequency intervals is solved. Compared with the conventional guard interval-based interference solution, the scheme disclosed by the invention does not need to consume additional spectrum resources for the purpose of interference solution, and the frequency utilization rate is improved. Furthermore, compared to conventional windowing and filtering based schemes, the scheme of the present disclosure is simpler and does not require shaping of the original signal at the shoulder, reducing system complexity and improving usability.

The techniques described in this disclosure may be used for various FDM systems, such as Orthogonal Frequency Division Multiplexing (OFDM). FDM partitions the overall system frequency into multiple sub-bands, which are also referred to as tones (tones), subcarriers, bins (bins), and so on. The basic idea of frequency division multiplexing is: the modulated signals are staggered in frequency position by adopting a method of modulating the multi-path signals with different frequencies, so that the aim of simultaneously transmitting the multi-path signals in one channel is fulfilled. Therefore, the respective signals of the frequency division multiplexing are signals which overlap in time and do not overlap in frequency spectrum. That is, the multiplexed signals are concurrently transmitted in different frequency bands.

Example implementations of the present disclosure are discussed in detail below. FIG. 4 shows a device according toA schematic block diagram of a communication system 400 of some implementations of the present disclosure. The system 400 includes a communication device 410 at the transmitting end and

communication devices

420 and 430 at the receiving end. In one example, communication device 410 desires to transmit signal S to communication device 420_AAnd transmits another signal S to the communication device 430_B. Hereinafter, for ease of discussion, the signal S transmitted to the communication device 420_AReferred to as first signal and transmitted to the communication device 430_BReferred to as the second signal. In downlink communications, the transmitting communication device 410 may be, for example, the network device 110 in fig. 1, and the receiving

communication devices

420, 430 may be the terminal devices 120 in fig. 1. In other communications, transmitting communication device 410 may be, for example, terminal device 120 in fig. 1, and receiving

communication devices

420, 430 may be network device 110 and/or terminal device 120 in fig. 1.

According to an implementation of the present disclosure, the communication device 410 transmits the first signal S_AAnd a second signal S_BMultiplexed on different frequencies and transmitted to both

communication devices

420 and 430. As used herein, "simultaneously transmit" refers to some or all of the information of different signals being transmitted at the same transmission time (e.g., time slot). Such transmission is called frequency division multiplexing.

In frequency division multiplexing based communication, the communication device 410 will transmit a signal S on a first subcarrier having a first frequency spacing_AAnd will transmit S on a second subcarrier having a second frequency spacing_B. The second subcarrier is adjacent to the first subcarrier and the second frequency spacing is different from the first frequency spacing. For example, the first frequency interval may be 30kHz and the second frequency interval may be 15 kHz. Of course, other frequency intervals are possible. In one example, f _ sc may be 15 × 2ⁿkHz to calculate the frequency interval f _ sc for different receiving communication devices, where n may take different non-negative integers for different receiving communication devices and/or traffic. Different scaling factors may also be used (e.g., scaling factor N-2)ⁿ) The frequency separation of the different receiving communication devices is determined. In some implementations, the second frequency interval is a multiple of two of the first frequency interval, orThe first frequency interval is a multiple of two of the second frequency interval. Of course, the frequency spacing of the different receiving communication devices may or may not be other multiples. In some implementations, the first and second signals S_AAnd S_BMay be transmitted on a plurality of subcarriers having corresponding frequency intervals, but adjacent subcarriers exist among the subcarriers.

As shown in fig. 4, the communication device 410 includes

encoders

412, 414, a multiplexer 416, and a transceiver 418. The encoder 412 is used for encoding the first signal S_AAnd the encoder 414 is for encoding the second signal S_B. Due to the first and second signals S_AAnd S_BAre transmitted on subcarriers of different frequency intervals, and thus it is difficult for the subcarriers to be orthogonal to each other, so that there is mutual interference. Such interference is due to different frequency spacings and may therefore be referred to as multi-subcarrier inter-interval interference, inter-frequency interval interference, or inter-signal interference. To avoid interference estimation of the received signal by the receiving

communication devices

420 and 430, the

encoders

412 and 414 of the communication device 410 estimate the interference of the further signal with the signal to be encoded, in particular the inter-frequency space interference.

In particular, the encoder 412 of the communication device 410 estimates that the second signal S is expected to be present at the receiving end of the first signal (i.e., the communication device 420) in the simultaneous transmission_BInduced pair of first signals S_AMay be referred to as a second interference, denoted as I_B). In calculating the second interference, the encoder 412 also provides the second signal S_BAs an input. Encoder 414 estimates the signal S expected to be present at the receiving end of the second signal (i.e., communication device 430) in the simultaneous transmission from the first signal S_AInduced pair of second signals S_BMay be referred to as a first interference, denoted as I_A). In calculating the second interference, the encoder 412 also combines the first signal S_AAs an input. Further, the encoder 412 generates the first signal S by decoding the first signal S_AIn removing the second interference I_BGenerating a transmission signal (which may be referred to as a first transmission signal, denoted T)_A) The encoder 414 generates the second signal S by converting the second signal S_BIn removing the first interference I_ATo generate a transmission signal (which may be referred to as a second transmission signal, denoted T)_B). That is, the transmission signal is equal to the signal to be transmitted (S)_AOr S_B) And the difference between the interference. The encoding process of

encoders

412 and 414 will be discussed in detail below.

First transmission signal T_AAnd a second transmission signal T_BIs provided to a multiplexer 416 for multiplexing. Multiplexer 416 may multiplex the first transmission signal T_AModulates to corresponding sub-carriers (including the first sub-carrier), and transmits the second transmission signal T_BModulated onto a corresponding subcarrier (including the second subcarrier). Multiplexer 416 may also perform other processing to achieve multiplexing of the two transmission signals in the frequency domain. The multiplexed signals are provided to the transceivers 418 to be simultaneously transmitted at respective transmission times.

The encoding process of the first and second signals in

encoders

412 and 414 is described in further detail below. When communication is performed with adjacent subcarriers of different frequency intervals, for the different frequency intervals, time-frequency transformation will be performed at the receiving end with corresponding time-frequency transformation parameters. For example, for a frequency interval of 30kHz, a 1024 point Fourier transform would be used, while for a frequency interval of 15kHz, a 2048 point Fourier transform would be used. Such a transformation will generate interference. That is, interference refers to the generation of out-of-band energy leakage from adjacent subcarriers due to the use of time-frequency transform parameters that do not match with the adjacent subcarriers when the receiving end performs time-frequency transform on a received signal. Such interference is also called out-of-band interference (out-of-band interference). The first and second interference I due to the different first and second frequency intervals_AAnd I_BThe magnitude of (c) is also different. In some implementations, the encoder 412 may determine that the first signal S is being encoded_ASignals outside the frequency band of the first subcarrier when performing a transformation with time-frequency transformation parameters for the second signal as first interference I_A. The encoder 414 may determine that the second signal S is being processed_BSignals outside the frequency band of the second subcarrier when performing a transformation with time-frequency transformation parameters for the first signal as second interference I_B. The particular transform technique from the time domain to the frequency domain may depend onConfiguration of a communication system. In some implementations, the time-frequency transform may include a Fast Fourier Transform (FFT), and the time-frequency transform parameters include a number of fourier transform points. It should be appreciated that other time-domain to frequency-domain transforms are possible and that out-of-band interference may be determined accordingly.

Determining the first and second signals S is given below_AAnd S_BSpecific examples of interference to each other. Suppose first and second signals S_AAnd S_BIs a frequency domain signal and for convenience of explanation it is assumed that the first frequency interval is twice the second frequency interval. In the time domain representation, the second signal S_BIs equal to the first signal S_AIs shown as a1 and a2, similar to the example shown in fig. 2B. In communication with the

communication devices

420 and 430, it is desirable that the signals received by the receiving

communication devices

420 and 430 are as follows, according to the principles of dirty paper coding:

wherein S_bRepresenting the second signal S_BOne frequency domain symbol of (a); t is_bRepresenting the symbol S after processing by the encoder 414_bThe transmission symbol of (1); s_a1And S_a2Representing a first signal S_ATwo frequency domain symbols of (a); t is_a1And T_a2Respectively, represent the symbols S processed by the encoder 412_a1And S_a2Two frequency domain symbols of (a); i is_aIndicating the presence of a first signal S in a transmission time slot_AIs corresponding symbol S_a1And S_a2The interference caused; i is_b1And I_b2Indicating that the second signal S is transmitted in the same transmission time slot_BIs corresponding symbol S_bThe first portion b1 and the second portion b 2. As can be seen from equation (1), the transmission signal transmitted by the communication device 410 may be identical to the signal that is originally expected to be transmitted after experiencing the inter-carrier interference.

Interference I_a、I_b1And I_b2Of adjacent sub-carriers which may cause interferenceThe out-of-band energy representation. Assume that the first signal S is received at the receiving communication device 420_AThe time-to-frequency domain transform performed is 1024-FFT, and the second signal S is received at the receiving communication device 430_BThe time-to-frequency domain transform performed is 2048-FFT. Thus, the out-of-band interference calculated by

encoders

412 and 414 can be expressed as:

wherein t is_aRepresenting a first signal S in a time-domain to frequency-domain transform_ATime domain symbols a1 and a2 (sum is 2048); t is t_b1And t_b2Respectively representing the second signal S in a time-domain to frequency-domain transformation_BTime-domain samples of time-domain symbol b (sum 2048); FFT₂₀₄₈() And FFT₁₀₂₄() Respectively representing the operation of 2048-FFT and 1024-FFT; and cut () represents an operation of truncating only the value of the out-of-band interference sample point. As can be seen from equation (2), the first signal S_AGenerated interference I_aDue to the fact that the first signal (the time domain of which represents t)_a) The FFT is performed using the time-frequency transform parameters of the second signal (i.e., FFT parameters of 2048 points). Second signal S_BThe resulting interference with the different symbols a1 and a2 of the first signal is due to the second signal (whose time domain represents t)_b1And t_b2) The FFT is performed using the time-frequency transform parameters of the first signal (i.e., the FFT parameters of 1024 points).

The

encoders

412 and 414 can determine the first and second transmission signals T according to equations (1) and (2)_AAnd T_BThe following transmission symbols:

transmitting a symbol T_a1、T_a2And T_bRespectively corresponding to the slave symbols S_a1、S_a2And S_bThe symbols after the interference are removed.

The time-to-frequency domain variation in a signal may be determined in a number of waysOut-of-band interference I generated during handover_a、I_b1And I_b2. In the interference estimation, the

encoders

412 and 414 know S in the frequency domain_AAnd S_B. In one implementation, to increase the computation speed,

encoders

412 and 414 may employ an iterative process to compute the interference. This iterative process may be based on equations (1) to (3) above, as follows.

First, the encoder 414 may pass through S_a1And S_a2Estimating

And then determining

The following were used:

wherein IFFT () represents an inverse fast fourier transform for performing a frequency domain to time domain transform;

and

denotes a slave symbol S_a1And S_a2A first estimation of the transformed time domain representation;

represents the interference I_aThe first estimation of (d); and is

Representation and symbol S_bA first estimate of the corresponding transmission symbol.

May then pass through in encoder 412

Estimating interference

And

and determining therefrom

And

the following were used:

in which the interference is

And

represents interference to I_b1And I_b2Is estimated for the first time, and

and

representation and symbol S_a1And S_a2A first estimate of the corresponding transmission symbol.

Interference

And

may be used by

encoders

414 and 412 to determine the transmitted signal, e.g., as determined by equation (1). To further improve the accuracy of the determination, the determination may also be continued to pass through in the encoder 414

And

calculating interference I_aSecond estimate of

And is determined therefrom as follows:

wherein

And

denotes a slave symbol S_a1And S_a2A second estimate of the transformed time domain representation;

represents the interference I_aThe second estimation of (2); and is

Representation and symbol S_bA second estimate of the corresponding transmitted symbol.

Further, based on the result of equation (6), equation (5) may be repeated, in encoder 412, by

Continuing to estimate interference

And

and determining therefrom

And

the following were used:

in which the interference is

And

represents interference to I_b1And I_b2Is estimated a second time, and

and

representation and symbol S_a1And S_a2A second estimate of the corresponding transmitted symbol.

Interference of the second estimation

And

may be used by

encoders

414 and 412 to determine the transmitted signal. As can be seen from the above iterative process, the step corresponding to formula (6) is similar to the repetition of the step corresponding to formula (4), and the step corresponding to formula (7) is the repetition of formula (5). In some implementations, the computations of equations (6) and (7) may also continue to be performed iteratively in the

encoders

414 and 412 to obtain further estimates of interference. Implementations of the present disclosure are not limited in this respect. For the first signal S_AAnd a second signal S_BMay similarly estimate interference and perform interference removal.

Fig. 5 shows an example structure of the

encoders

412 and 414 for performing the iterative interference determination process described above. In particular, in the encoder 414, the module 512 may be used forPerforming on the first signal S_AFor example, the IFFT-related operations in equations (4) and (6). The module 514 may be used to perform FFT operations on the time domain signal, such as those involving FFT in equations (4) and (6). Further, module 516 may be configured to perform the determination of out-of-band interference. The operations of the modules 512 to 516 may be repeatedly performed to determine the first signal S_AFor the second signal S_BFirst interference I of_A. Interference I determined by Block 516_ACan be associated with the second signal S_BAre input together into a combiner 518 so that the second signal S can be derived from_BRemoving the first interference I_AGenerating a second transmission signal T_B。

Similarly, in the encoder 412, the module 522 may be used to perform the comparison of the second signal S_BFor example, the IFFT-related operations in equations (5) and (7). The module 524 may be used to perform FFT operations on the time domain signal, such as the operations involving FFT in equations (5) and (7). Further, the module 526 may be used to perform out-of-band interference determination. The operations of the modules 522 to 526 may be repeatedly performed to determine the second signal S_BFor the first signal S_ASecond interference I_B. Interference I determined by module 526_BCan be compared with the first signal S_AAre input together to the combiner 528 so that the first signal S can be derived from_ARemoving the second interference I_BGenerating a first transmission signal T_A。

The process of interference determination has been described above with respect to specific frequency intervals, time-frequency transform parameters, techniques, and the like. However, it should be understood that interference may be similarly calculated in implementations having other parameters, such as other frequency spacing relationships, other time-frequency transform parameters, and techniques. Of course, various other techniques may also be employed to determine mutual interference between adjacent subcarriers having different frequency spacing. Furthermore, the above relates to the first and second signals S_AAnd S_BThe description is made for an example of a frequency domain signal. In other implementations, the communication device 410 may obtain the first and second signals in the time domain, and may also determine the first sum by estimating and removing interference accordinglyA second transmission signal.

In the above description, it was discussed that the transmitting communication device 410 simultaneously transmits two signals S to two receiving

devices

420 and 430_AAnd S_BThe case (1). In other implementations, the communication device 410 may also transmit three or more signals simultaneously, and the signals may be transmitted on subcarriers having different frequency spacing. These subcarriers are adjacent to each other. In this case, for a specific signal (e.g., the first signal S)_A) If used for transmitting the first signal S_ANot only with the second signal S_BIs adjacent to the second subcarrier and is also used for transmitting the third signal S_CIs adjacent, the communication device 410 may also calculate accordingly the third signal S to be transmitted by the simultaneous transmission_CInduced pair of first signals S_AThe third interference of (2). Except from the first signal S_AIn which the second signal S is removed_BIn addition to the second interference caused, the encoder 412 of the communication device 410 also derives the first signal S from the first signal S_ARemoving the third signal S_CThe third interference caused to generate the first transmission signal.

The third signal may be transmitted to another communication device or may be transmitted as other traffic data for

communication device

410 or 420. Accordingly, to transmit the third signal, the encoder 412 of the communication device 410 may also calculate the signal S to be transmitted by the first signal in a simultaneous transmission_AInduced pair of third signals S_CAnd from the third signal S_CRemoving the fourth interference to generate a third transmission signal T_C. The calculation for the third and fourth interferences can also be done in a similar way as described above. In some implementations, the communication device 410 may include an additional separate encoder for the third signal S_CThe coding of (2). The third transmit signal is provided to multiplexer 416 for multiplexing along with the first and second transmit signals. The third transmission signal may be multiplexed onto a third subcarrier of the same transmission time. The multiplexed signals are provided to the transceiver 418 to be transmitted simultaneously at the respective transmission times.

The multiplexed signal may be transmitted to

communication devices

420 and 430 via channel 402. Channel 402 may be a wireless connection and/or a wired connection between communication devices. With continued reference to fig. 4, on the receive side, a communication device 420 receives a signal from a communication device 410 via a channel 402. The communication device 420 includes a transceiver 422, a transducer 424, and a controller 426. Transceiver 422 is used to receive signals on a first subcarrier having a first frequency spacing. The received signal may be a time domain signal. Thus, the transformer 424 of the communication device 420 may perform a time domain to frequency domain transformation, obtaining the first received signal.

For frequency division multiplexing reasons, the communication device 410 transmits the transmission signal T_ABut due to interference I of the simultaneously transmitted signals_BThe received signal actually obtained by the communication device 420 is T_A+I_B(without taking into account other interference). That is, the received signal includes the second signal S_BInduced interference I_BAnd removing, by the transmitting device, the interference I from the first signal_BAnd the generated transmission signal T_A. The controller 426 of the communication device 420 may not need to remove the second signal S without considering other interference_BThe induced interference, and the first received signal is directly processed into the first signal (i.e., the desired signal).

In some cases, the channel 402 used for transmission from the communication device 410 to the communication device 420 may have noise interference. Such noise interference may be caused by, for example, additive white noise N (0, σ)²) And (6) modeling. Therefore, the signal after being transformed by the transformer 424 may be T_A+I_B+σ². Therefore, the controller 426 may further perform a process of eliminating noise interference of the channel 402, etc., to obtain the first signal T_A+I_B. Of course, the controller 426 may also perform other processing on the first received signal, and implementations of the disclosure are not limited in this respect.

Similarly, the communication device 430 may also include a transceiver 432, a transducer 434, and a controller 436. The transceiver 432 is configured to receive signals from the communication device 410 on a second subcarrier having a second frequency spacing. Converter 434 is used for receiving the received time domain signalThe signal performs a time-to-frequency domain transform to obtain a second received signal. The second received signal includes interference I due to interference introduced by the simultaneously transmitted first signals_AAnd a transmission signal T_B. The controller 436 may directly process the second received signal into a second signal (i.e., the desired signal) without considering other interference. In other implementations, the controller 436 may also perform further processing on the second received signal, such as noise and interference cancellation of the channel.

In the example of fig. 4, the first and second signals are transmitted to different communication devices. However, it should be understood that in other implementations, the first and second signals may be transmitted as different traffic data for the same device. In such an implementation,

communication device

410 or 420 in fig. 4 may act as different receiving portions of the same device for receiving corresponding signals.

It should be understood that although described above with respect to the structure of the communication device at the transmitting end and the receiving end, the communication device may also include other functional modules and/or other configured structures. In some implementations, operations described above as being performed by two or more functional modules may be performed by a single functional module. In other implementations, operations described above as being performed by a single functional module may also be performed by multiple functional modules. The scope of the present disclosure is not limited in this respect.

Fig. 6 illustrates a flow diagram of a process 600 for frequency division multiplexing-based communication in accordance with some implementations of the present disclosure. It is to be appreciated that process 600 may be implemented, for example, at communication device 410 as shown in fig. 4 or at device 110 or 120 that transmits signals as shown in fig. 1. For ease of description, process 600 is described below in conjunction with FIG. 4. At 610, the communication device 410 determines a first interference expected to be caused by the first signal at a receiving end of the second signal and a second interference expected to be caused by the second signal at the receiving end of the first signal in the simultaneous transmission of the first signal and the second signal. The first signal will be transmitted on a first subcarrier having a first frequency spacing and the second signal will be transmitted on a second subcarrier having a second frequency spacing. The second subcarrier is adjacent to the first subcarrier and the second frequency spacing is different from the first frequency spacing. At 620, the communication device 410 generates a first transmission signal by removing the second interference from the first signal. At 630, the communication device 410 generates a second transmission signal by removing the first interference from the second signal. At 640, the communication device 410 multiplexes the first transmission signal and the second transmission signal for simultaneous transmission.

In some implementations, determining the first interference and the second interference may include determining a signal outside a frequency band of the first subcarrier as the first interference when performing a transform on the first signal with time-frequency transform parameters for the second signal, and determining a signal outside a frequency band of the second subcarrier as the second interference when performing a transform on the second signal with time-frequency transform parameters for the first signal.

In some implementations, the time-domain to frequency-domain transform may include a fast fourier transform, and wherein the time-frequency transform parameters include a number of fourier transform points.

In some implementations, generating the first transmission signal may further include: obtaining a third signal to be transmitted on a third subcarrier having a third frequency interval in the frequency domain, the third subcarrier being adjacent to the first subcarrier and the third frequency interval being different from the first frequency interval; determining a third interference to the first signal that would be caused by the third signal in the simultaneous transmission of the third subcarrier and the first subcarrier; and generating the first transmission signal by further removing the third interference from the first signal.

In some implementations, multiplexing may further include: determining a fourth interference of the first signal with the third signal in the transmission; generating a third transmission signal by removing the fourth interference from the third signal; and further multiplexing the third transmission signal with the first transmission signal and the second transmission signal for simultaneous transmission.

In some implementations, the second frequency interval may be a multiple of two of the first frequency interval, or the first frequency interval may be a multiple of two of the second frequency interval.

Fig. 7 illustrates a flow diagram of a process 700 for frequency division multiplexing-based communication in accordance with some implementations of the present disclosure. It is to be appreciated that process 700 may be implemented, for example, at

communication device

420 or 430 as shown in fig. 4, or device 110 or 120 receiving a signal as shown in fig. 1. For ease of description, the process 700 is described below in connection with the communication device 420 of fig. 4. It should be understood that the communication device 430 may perform operations similarly. At 710, the communication device 420 receives a first received signal on a first subcarrier having a first frequency spacing. The first received signal is associated with a first signal transmitted by a transmitting device, the first signal being transmitted simultaneously with a second signal on a second subcarrier having a second frequency spacing. The second subcarrier is adjacent to the first subcarrier and the second frequency spacing is different from the first frequency spacing. The first received signal contains interference that has been caused by the second signal and a transmission signal generated by the transmitting device removing the interference from the first signal. At 720, the communication device 420 processes the first received signal to obtain a first signal without removing interference.

In some implementations, the second frequency interval is a multiple of two of the first frequency interval, or the first frequency interval is a multiple of two of the second frequency interval.

Fig. 8 illustrates a block diagram of an apparatus 800 in accordance with some implementations of the present disclosure. It is to be appreciated that the apparatus 800 may be implemented on the side of the communication device 410 shown in fig. 4 or at the device 110 or 120 transmitting the signal shown in fig. 1. As shown in fig. 8, the apparatus 800 comprises a determining unit 810 for determining a first interference expected to be caused by the first signal at the receiving end of the second signal and a second interference expected to be caused by the second signal at the receiving end of the first signal in the simultaneous transmission of the first signal and the second signal. The first signal will be transmitted on a first subcarrier having a first frequency spacing and the second signal will be transmitted on a second subcarrier having a second frequency spacing. The second subcarrier is adjacent to the first subcarrier and the second frequency spacing is different from the first frequency spacing. The apparatus 800 further comprises a first generating unit 820 for generating a first transmission signal by removing the second interference from the first signal. The apparatus 800 further comprises a second generating unit 830 for generating a second transmission signal by removing the first interference from the second signal. Furthermore, the apparatus 800 further comprises a multiplexing unit 840 for multiplexing the first transmission signal and the second transmission signal for simultaneous transmission.

In some implementations, the determining unit 810 may be configured to: determining a signal outside a frequency band of the first subcarrier as a first interference when performing a transform on the first signal with time-frequency transform parameters for the second signal; and determining a signal outside the frequency band of the second subcarrier as the second interference when the transform is performed on the second signal with the time-frequency transform parameters for the first signal.

In some implementations, the apparatus 800 may further include: an acquisition unit for acquiring a third signal to be transmitted on a third subcarrier having a third frequency interval in the frequency domain, the third subcarrier being adjacent to the first subcarrier and the third frequency interval being different from the first frequency interval. The determining unit 810 may be configured to determine a third interference to the first signal that would be caused by the third signal in the simultaneous transmission of the third subcarrier and the first subcarrier. The first generating unit 820 may be configured to generate the first transmission signal by further removing the third interference from the first signal.

In some implementations, the determining unit 810 may be further configured to: a fourth interference of the first signal with the third signal in the transmission is determined. The apparatus 800 may further comprise a third generating unit for generating a third transmission signal by removing the fourth interference from the third signal. Multiplexing unit 840 may further be configured to multiplex the third transmission signal with the first transmission signal and the second transmission signal for simultaneous transmission.

Fig. 9 illustrates a block diagram of an apparatus 900 according to some implementations of the present disclosure. It is understood that the apparatus 900 may be implemented on the side of the

communication device

420 or 430 shown in fig. 4, or at the device 110 or 120 receiving the signal shown in fig. 1. As shown in fig. 9, the apparatus 900 comprises a receiving unit 910 configured to receive a first received signal on a first subcarrier having a first frequency spacing. The first received signal is associated with a first signal transmitted by a transmitting device, the first signal being transmitted simultaneously with a second signal on a second subcarrier having a second frequency spacing. The second subcarrier is adjacent to the first subcarrier and the second frequency spacing is different from the first frequency spacing. The first received signal contains interference that has been caused by the second signal and a transmission signal generated by the transmitting device removing the interference from the first signal. The apparatus 900 further comprises a processing unit 920 for processing the first received signal to obtain a first signal without removing interference.

It should be understood that each unit recited in the apparatus 800 and the apparatus 900 corresponds to each step in the

processes

600 and 700 described with reference to fig. 6-7, respectively. Moreover, the operations and features described above in connection with fig. 4-5 are equally applicable to 800 and apparatus 900 and the units contained therein, and have the same effect, and detailed description is omitted.

800 and the elements included in the apparatus 900 may be implemented in a variety of ways including software, hardware, firmware, or any combination thereof. In one implementation, one or more of the units may be implemented using software and/or firmware, such as computer-executable instructions stored on a storage medium. In addition to, or in the alternative to, computer-executable instructions, some or all of the elements in 800 and apparatus 900 may be implemented at least in part by one or more hardware logic components. By way of example, and not limitation, exemplary types of hardware logic components that may be used include Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), Application Specific Standards (ASSPs), systems on a chip (SOCs), Complex Programmable Logic Devices (CPLDs), and so forth.

The elements shown in fig. 8 and 9 may be implemented partially or wholly as hardware modules, software modules, firmware modules, or any combination thereof. In particular, in some implementations, the above-described flows, methods or processes may be implemented by hardware in a communication device. For example, a communication device may implement

processes

600 and 700 with its transmitter, receiver, transceiver, and/or processor or controller.

Fig. 10 illustrates a simplified block diagram of a device 1000 suitable for implementing implementations of the present disclosure. Device 1000 may be used to implement a communication device, such as network device 110, terminal device 120 shown in fig. 1, or

communication devices

410, 420, or 430 shown in fig. 4. As shown, device 1000 includes one or more processors 1010, one or more memories 1020 coupled to processor(s) 1010, one or more transmitters and/or receivers (TX/RX)1040 coupled to processor 1010.

The processor 1010 may be of any type suitable to the local technical environment, and may include one or more of the following as non-limiting examples: general purpose computers, special purpose computers, microprocessors, Digital Signal Processors (DSPs) and processors based on a multi-core processor architecture. Device 1000 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time with a clock synchronized to the main processor.

The memory 1020 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as non-transitory computer-readable storage media, semiconductor-based storage devices, magnetic storage devices and systems, optical storage devices and systems, fixed memory and removable memory, as non-limiting examples.

Memory 1020 stores at least a portion of program 1030. TX/RX 1040 is used for bi-directional communication. TX/RX 1040 has at least one antenna to facilitate communications. A communication interface may represent any interface necessary to communicate with other devices.

Programs 1030 are assumed to include program instructions that, when executed by associated processor 1010, cause device 1000 to perform implementations of the present disclosure as discussed above with reference to fig. 4-7. That is, implementations of the present disclosure may be implemented by computer software executable by the processor 1010 of the device 1000, or by a combination of software and hardware.

In general, various example implementations of the disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Certain aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. For example, in some implementations, various examples of the disclosure (e.g., a method, apparatus, or device) may be partially or fully implemented on a computer-readable medium. While various aspects of the implementations of the disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

By way of example, implementations of the disclosure may be described in the context of computer-executable instructions, such as program modules, being included in a device executing on a physical or virtual processor of a target. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various implementations, the functionality of the program modules may be combined or divided among the program modules described. Computer-executable instructions for program modules may be executed within local or distributed devices. In a distributed facility, program modules may be located in both local and remote memory storage media.

Computer program code for implementing the methods of the present disclosure may be written in one or more programming languages. These computer program codes may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the computer or other programmable data processing apparatus, cause the functions/acts specified in the flowchart and/or block diagram block or blocks to be performed. The program code may execute entirely on the computer, partly on the computer, as a stand-alone software package, partly on the computer and partly on a remote computer or entirely on the remote computer or server.

In the context of this disclosure, a computer readable medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The computer readable medium may be a machine readable signal medium or a machine readable storage medium. A computer readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More detailed examples of a machine-readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical storage device, a magnetic storage device, or any suitable combination thereof.

Additionally, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking or parallel processing may be beneficial. Likewise, while the above discussion contains certain specific implementation details, this should not be construed as limiting the scope of any invention or claims, but rather as a description of specific implementations that may be directed to a particular invention. Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A method implemented at a communication device, comprising:

determining a first interference expected to be caused by a first signal at a receiving end of a second signal and a second interference expected to be caused by the second signal at the receiving end of the first signal in a simultaneous transmission of the first signal and the second signal, the first signal to be transmitted on a first subcarrier having a first frequency spacing, the second signal to be transmitted on a second subcarrier having a second frequency spacing, the second subcarrier being adjacent to the first subcarrier, and the second frequency spacing being different from the first frequency spacing;

generating a first transmission signal by removing the second interference from the first signal;

generating a second transmission signal by removing the first interference from the second signal; and

multiplexing the first transmission signal and the second transmission signal for the simultaneous transmission.

2. The method of claim 1, wherein determining the first interference and the second interference comprises:

determining a signal outside a frequency band of the first subcarrier as the first interference when performing a transform on the first signal with time-frequency transform parameters for the second signal; and

determining a signal outside the frequency band of the second subcarrier as the second interference when performing a transform on the second signal with time-frequency transform parameters for the first signal.

3. The method of claim 2, wherein the transform comprises a fast fourier transform, and wherein the time-frequency transform parameters comprise a number of fourier transform points.

4. The method of claim 1, wherein generating the first transmission signal further comprises:

obtaining a third signal to be transmitted on a third subcarrier having a third frequency spacing in the frequency domain, the third subcarrier being adjacent to the first subcarrier and the third frequency spacing being different from the first frequency spacing;

determining a third interference to the first signal that would be caused by the third signal in the simultaneous transmission of the third subcarrier and the first subcarrier; and

generating the first transmission signal by further removing the third interference from the first signal.

5. The method of claim 4, wherein the multiplexing further comprises:

determining a fourth interference of the first signal to the third signal in the transmission;

generating a third transmission signal by removing the fourth interference from the third signal; and

further multiplexing the third transmission signal with the first transmission signal and the second transmission signal for the simultaneous transmission.

6. The method of claim 1, wherein the second frequency interval is a multiple of two of the first frequency interval, or the first frequency interval is a multiple of two of the second frequency interval.

7. A method implemented at a communication device, comprising:

receiving a first receive signal on a first subcarrier having a first frequency spacing, the first receive signal being associated with a first signal transmitted by a transmitting device, the first signal being transmitted simultaneously with a second signal on a second subcarrier having a second frequency spacing, the second subcarrier being adjacent to the first subcarrier, the second frequency spacing being different from the first frequency spacing, and the first receive signal containing interference that has been caused by the second signal and a transmit signal generated by the transmitting device removing the interference from the first signal; and

processing the first received signal to obtain the first signal without removing the interference.

8. The method of claim 7, wherein the second frequency interval is a multiple of two of the first frequency interval, or the first frequency interval is a multiple of two of the second frequency interval.

9. A communication device, comprising:

a processor; and

a memory coupled with the processor, the memory having instructions stored therein that, when executed by the processor, cause the communication device to perform acts comprising:

10. The communication device of claim 9, wherein determining the first interference and the second interference comprises:

11. The communication device of claim 10, wherein the transform comprises a fast fourier transform, and wherein the time-frequency transform parameters comprise a number of fourier transform points.

12. The communication device of claim 9, wherein generating the first transmission signal further comprises:

13. The communication device of claim 12, wherein the multiplexing further comprises:

14. The communication device of claim 9, wherein the second frequency interval is a multiple of two of the first frequency interval, or the first frequency interval is a multiple of two of the second frequency interval.

15. A communication device, comprising:

a processor; and

16. The communication device of claim 15, wherein the second frequency interval is a multiple of two of the first frequency interval, or the first frequency interval is a multiple of two of the second frequency interval.

17. A computer-readable medium having stored thereon computer-executable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the method of any one of claims 1-6.

18. A computer-readable medium having stored thereon computer-executable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the method of any one of claims 7 and 8.