Simultaneous transmission in multiple frequency bands

Abstract

The invention relates to simultaneous transmission in multiple frequency bands. A communication device determines whether simultaneous transmissions in a first frequency band and a second frequency band are to be synchronized in time. In response to determining that simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time, the communication device transmits a first packet in the first frequency band starting from a first time and a second packet in the second frequency band starting from the first time. In response to determining that simultaneous transmissions in the first frequency band and the second frequency band are not synchronized in time, the communication device transmits a third packet in the first frequency band starting from a second time, and transmits a fourth packet in the second frequency band starting from a third time different from the second time.

Description

[0001] Division Explanation

[0002] This application is a divisional application of a Chinese patent application with application number 202080038418.5 and titled "Simultaneous Transmission in Multiple Frequency Bands", which was filed on April 10, 2020.

[0003] Cross - Reference to Related Applications

[0004] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 832,757, titled "Extra High Throughput (EHT) Aggregated PLCP Protocol Data Unit (PPDU)", filed on April 11, 2019, which is incorporated herein by reference in its entirety. Technical Field

[0005] The present disclosure generally relates to wireless communication systems and, more particularly, to data transmission and reception over multiple communication channels. Background Art

[0006] Wireless local area networks (WLANs) have evolved rapidly over the past two decades, and the development of WLAN standards such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard family has increased the single-user peak data rate. One way to increase the data rate is to increase the frequency bandwidth of the communication channels used in the WLAN. For example, the IEEE 802.11n standard allows aggregating two 20 MHz sub-channels to form a 40 MHz aggregated communication channel, while the newer IEEE 802.11ax standard allows aggregating up to eight 20 MHz sub-channels to form an aggregated communication channel up to 160 MHz. A new iteration of the IEEE 802.11 standard has now begun, which is known as the IEEE 802.11be standard, or the extremely high throughput (EHT) WLAN. The IEEE 802.11be standard may allow aggregating up to 16 20 MHz sub-channels (or possibly even more) to form an aggregated communication channel up to 320 MHz (or possibly even wider aggregated communication channels). Additionally, the IEEE 802.11be standard may allow aggregating 20 MHz sub-channels in different frequency bands (e.g., separated by a frequency gap) to form a single aggregated channel. Additionally, the IEEE 802.11be standard may allow aggregating 20 MHz sub-channels in different radio frequency (RF) bands to form a single aggregated channel.

[0007] The current draft of the IEEE 802.11ax standard (referred to herein as the "IEEE 802.11ax standard" for simplicity) defines an "80+80" transmission mode in which a communication device transmits simultaneously in two 80 MHz channel segments within a single radio frequency (RF) band. The two 80 MHz channel segments may be frequency-separated within a single RF band. Transmissions in the two 80 MHz channel segments are synchronized, i.e., the transmissions start at the same start time and end at the same end time. SUMMARY OF THE INVENTION

[0008] In one embodiment, a method for simultaneous transmission in multiple frequency segments includes: determining, at a communication device, whether simultaneous transmissions in a first frequency segment and a second frequency segment are to be synchronized in time; in response to the communication device determining that the simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in time, transmitting a first packet in the first frequency segment starting from a first time and transmitting a second packet in the second frequency segment starting from the first time; and in response to the communication device determining that the simultaneous transmissions in the first frequency segment and the second frequency segment are to be non-synchronized in time, transmitting a third packet in the first frequency segment starting from a second time and transmitting a fourth packet in the second frequency segment starting from a third time different from the second time.

[0009] In another embodiment, a communication device includes a wireless network interface device that includes one or more integrated circuit (IC) devices and multiple radio frequency (RF) radio devices, including at least a first RF radio device and a second RF radio device, wherein the multiple RF radio devices are at least partially implemented on the one or more IC devices. The one or more IC devices are configured to: determine whether simultaneous transmissions in a first frequency segment and a second frequency segment are to be synchronized; and in response to the communication device determining that the simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized, control the first RF radio device to transmit a first packet in the first frequency segment starting from a first time and control the second RF radio device to transmit a second packet in the second frequency segment starting from the first time. The one or more IC devices are further configured to: in response to the communication device determining that the simultaneous transmissions in the first frequency segment and the second frequency segment are to be non-synchronized, control the first RF radio device to transmit a third packet in the first frequency segment starting from a second time and control the second RF radio device to transmit a fourth packet in the second frequency segment starting from a third time different from the second time. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a block diagram of an exemplary wireless local area network (WLAN) in which corresponding RF signals are transmitted simultaneously in corresponding frequency segments.

[0011] Figure 2AA diagram of an example synchronous transmission over different channel segments according to an embodiment.

[0012] Figure 2B A diagram of an example asynchronous transmission over different channel segments according to an embodiment.

[0013] Figure 3A A diagram of an example synchronous downlink multi-user (MU) orthogonal frequency division multiple access (OFDMA) transmission over different channel segments according to an embodiment.

[0014] Figure 3B A diagram of an example asynchronous MU OFDMA transmission over different channel segments according to an embodiment.

[0015] Figure 4 A flowchart of an example method for transmission via multiple frequency bands in a wireless communication network according to an embodiment.

[0016] Figure 5 A diagram of an example network interface device configured for multi-channel segment operation according to an embodiment.

[0017] Figure 6A A diagram of an example packet transmitted in a corresponding frequency band according to an embodiment.

[0018] Figure 6B A diagram of an example non-legacy preamble included in an example packet according to some embodiments. Figure 6A in accordance with some embodiments DETAILED DESCRIPTION

[0019] Next-generation wireless local area network (WLAN) protocols (e.g., the IEEE 802.11be standard, sometimes referred to as the extremely high throughput (EHT) WLAN standard) may allow simultaneous transmissions in different channel segments. The different channel segments may be in a single radio frequency (RF) band or in different RF bands. The different channel segments may have the same bandwidth or different bandwidths.

[0020] The IEEE 802.11ax standard allows synchronous transmissions in two 80 MHz channel segments (i.e., the transmissions start at the same start time and end at the same end time) (referred to as "80+80" transmissions), and requires that the two 80 MHz channel segments be idle simultaneously for synchronous transmission. However, for many WiFi deployments, it is often difficult to find a time when both 80 MHz channel segments are idle, thus limiting the practicality of the 80+80 transmission mode.

[0021] In some embodiments described below, the communication device is configured to transmit synchronously in different channel segments in some scenarios (e.g., the transmissions start at the same start time), and transmit asynchronously in different channel segments in other scenarios (e.g., the transmissions do not need to start at the same start time). At least in some embodiments, transmitting asynchronously in different channel segments does not require the different channel segments to be idle at the same time. Thus, compared with a communication system that always requires transmissions in different channel segments to be synchronized (e.g., the transmissions start at the same start time) and the different channel segments to be idle simultaneously, at least in some embodiments and / or scenarios, it allows the different channel segments to be used simultaneously more frequently.

[0022] Figure 1 is a block diagram of an example wireless local area network (WLAN) 110 according to an embodiment. The WLAN 110 includes an access point (AP) 114, and the AP 114 includes a host processor 118 coupled to a network interface device 122. The network interface device 122 includes one or more media access control (MAC) processors 126 (sometimes referred to herein as "MAC processor 126" for brevity) and one or more physical layer (PHY) processors 130 (sometimes referred to herein as "PHY processor 130" for brevity). The PHY processor 130 includes a plurality of transceivers 134, and the transceivers 134 are coupled to a plurality of antennas 138. Although Figure 1 three transceivers 134 and three antennas 138 are shown, in other embodiments, the AP 114 includes other suitable numbers (e.g., 1, 2, 4, 5, etc.) of transceivers 134 and antennas 138. In some embodiments, the AP 114 includes more antennas 138 than transceivers 134 and utilizes antenna switching techniques.

[0023] The network interface device 122 is implemented using one or more integrated circuits (ICs) configured to operate as described below. For example, the MAC processor 126 can be implemented at least in part on a first IC, and the PHY processor 130 can be implemented at least in part on a second IC. As another example, at least a portion of the MAC processor 126 and at least a portion of the PHY processor 130 can be implemented on a single IC. For example, the network interface device 122 can be implemented using a system on a chip (SoC), where the SoC includes at least a portion of the MAC processor 126 and at least a portion of the PHY processor 130.

[0024] In one embodiment, host processor 118 includes a processor configured to execute machine-readable instructions stored in a memory device (not shown) such as random access memory (RAM), read only memory (ROM), flash memory, etc. In one embodiment, host processor 118 may be implemented at least in part on a first IC, and network device 122 may be implemented at least in part on a second IC. As another example, host processor 118 and at least a portion of network interface device 122 may be implemented on a single IC.

[0025] In various embodiments, the MAC processor 126 and / or the PHY processor 130 of AP 114 are configured to generate data units and process received data units that conform to a WLAN communication protocol, such as a communication protocol that conforms to the IEEE 802.11 standard or other suitable wireless communication protocol. For example, MAC processor 126 may be configured to implement MAC layer functions, including MAC layer functions of a WLAN communication protocol, and PHY processor 130 may be configured to implement PHY functions, including PHY functions of a WLAN communication protocol. For example, MAC processor 126 may be configured to generate MAC layer data units, such as MAC service data units (MSDUs), MAC protocol data units (MPDUs), aggregated MPDUs (A-MPDUs), etc., and provide the MAC layer data units to PHY processor 130. The MPDUs and A-MPDUs exchanged between MAC processor 126 and PHY processor 130 are sometimes referred to as physical layer convergence procedure (PLCP) (or simply "PHY") service data units (PSDUs).

[0026] PHY processor 130 may be configured to receive a MAC layer data unit (or PSDU) from MAC processor 126 and encapsulate the MAC layer data unit (or PSDU) to generate a PHY data unit such as a PLCP (or "PHY") protocol data unit (PPDU) for transmission via antenna 138. Similarly, PHY processor 130 may be configured to receive a PHY data unit received via antenna 138 and extract the MAC layer data unit encapsulated within the PHY data unit. PHY processor 130 may provide the extracted MAC layer data unit to MAC processor 126, which processes the MAC layer data unit.

[0027] PHY data units are sometimes referred to herein as "packets", and MAC layer data units are sometimes referred to herein as "frames".

[0028] According to one embodiment, with respect to generating one or more radio frequency (RF) signals for transmission, the PHY processor 130 is configured to process (which may include modulation, filtering, etc.) data corresponding to a PPDU to generate one or more digital baseband signals, and convert the (multiple) digital baseband signals into one or more analog baseband signals. In addition, the PHY processor 130 is configured to up-convert the one or more analog baseband signals into one or more RF signals for transmission via one or more antennas 138.

[0029] With respect to receiving one or more RF signals, the PHY processor 130 is configured to down-convert the one or more RF signals into one or more analog baseband signals, and convert the one or more analog baseband signals into one or more digital baseband signals. The PHY processor 130 is further configured to process (which may include demodulation, filtering, etc.) the one or more digital baseband signals to generate a PPDU.

[0030] The PHY processor 130 includes amplifiers (e.g., low noise amplifiers (LNAs), power amplifiers, etc.), radio frequency (RF) down-converters, RF up-converters, multiple filters, one or more analog-to-digital converters (ADCs), one or more digital-to-analog converters (DACs), one or more discrete Fourier transform (DFT) calculators (e.g., fast Fourier transform (FFT) calculators), one or more inverse discrete Fourier transform (IDFT) calculators (e.g., inverse fast Fourier transform (IFFT) calculators), one or more modulators, one or more demodulators, etc.

[0031] The PHY processor 130 is configured to generate one or more RF signals that are provided to one or more antennas 138. The PHY processor 130 is further configured to receive one or more RF signals from one or more antennas 138.

[0032] According to some embodiments, the MAC processor 126 is configured to control the PHY processor 130 to generate one or more RF signals by, for example, providing one or more MAC layer data units (e.g., MPDUs) to the PHY processor 130 and optionally providing one or more control signals to the PHY processor 130. In one embodiment, the MAC processor 126 includes a processor configured to execute machine-readable instructions stored in a memory device (not shown) such as RAM, read-only ROM, flash memory, etc. In another embodiment, the MAC processor 126 includes a hardware state machine.

[0033] According to one embodiment, the MAC processor 126 includes or implements a multi-channel segment transmission controller 142, which is configured to determine when transmissions in different channel segments are to be synchronously transmitted (e.g., the transmissions start at the same start time), and when transmissions in different channel segments can be asynchronously transmitted (e.g., the transmissions do not need to start at the same start time). According to some embodiments, when transmissions in different channel segments are to be synchronously transmitted, the multi-channel segment transmission controller 142 prompts the PHY processor 130 to start the transmissions in different channel segments at the same time. According to some embodiments, when transmissions in different channel segments are to be asynchronously transmitted, the multi-channel segment transmission controller 142 prompts the PHY processor 130 to start the transmissions in different channel segments at different times.

[0034] In one embodiment, the multi-channel segment transmission controller 142 is implemented by a processor executing machine-readable instructions stored in a memory, where the machine-readable instructions cause the processor to perform the actions described in more detail below. In another embodiment, the multi-channel segment transmission controller 142 additionally or alternatively includes hardware circuitry configured to perform the actions described in more detail below. In some embodiments, the hardware circuitry includes one or more hardware state machines configured to perform the actions described in more detail below.

[0035] The WLAN 110 includes a plurality of client stations 154. Although three client stations 154 are shown in Figure 1 , in various embodiments, the WLAN 110 includes other suitable numbers (e.g., 1, 2, 4, 5, 6, etc.) of client stations 154. The client station 154-1 includes a host processor 158 coupled to a network interface device 162. The network interface device 162 includes one or more MAC processors 166 (sometimes referred to herein as "MAC processors 166" for brevity) and one or more PHY processors 170 (sometimes referred to herein as "PHY processors 170" for brevity). The PHY processor 170 includes a plurality of transceivers 174, and the transceivers 174 are coupled to a plurality of antennas 178. Although Figure 1 three transceivers 174 and three antennas 178 are shown, in other embodiments, the client station 154-1 includes other suitable numbers (e.g., 1, 2, 4, 5, etc.) of transceivers 174 and antennas 178. In some embodiments, the client station 154-1 includes more antennas 178 than transceivers 174 and utilizes antenna switching techniques.

[0036] The network interface device 162 is implemented using one or more ICs configured to operate as described below. For example, the MAC processor 166 may be implemented on at least a first IC, and the PHY processor 170 may be implemented on at least a second IC. As another example, at least a portion of the MAC processor 166 and at least a portion of the PHY processor 170 may be implemented on a single IC. For example, the network interface device 162 may be implemented using a SoC that includes at least a portion of the MAC processor 166 and at least a portion of the PHY processor 170.

[0037] In one embodiment, the host processor 158 includes a processor configured to execute machine-readable instructions stored in a memory device (not shown) such as RAM, ROM, flash memory, etc. In one embodiment, the host processor network device 162 may be at least partially implemented on a first IC, and the network device 162 may be at least partially implemented on a second IC. As another example, the host processor 158 and at least a portion of the network interface device 162 may be implemented on a single IC.

[0038] In various embodiments, the MAC processor 166 and the PHY processor 170 of the client device 154-1 are configured to generate data units and process received data units that conform to a WLAN communication protocol or another suitable communication protocol. For example, the MAC processor 166 may be configured to implement MAC layer functions, including the MAC layer functions of the WLAN communication protocol, and the PHY processor 170 may be configured to implement PHY functions, including the PHY functions of the WLAN communication protocol. The MAC processor 166 may be configured to generate MAC layer data units such as MSDU, MPDU, etc., and provide the MAC layer data units to the PHY processor 170. The PHY processor 170 may be configured to receive the MAC layer data units from the MAC processor 166, and encapsulate the MAC layer data units to generate PHY data units such as PPDU for transmission via the antenna 178. Similarly, the PHY processor 170 may be configured to receive PHY data units received via the antenna 178, and extract the MAC layer data units encapsulated within the PHY data units. The PHY processor 170 may provide the extracted MAC layer data units to the MAC processor 166, and the MAC processor 166 processes the MAC layer data units.

[0039] According to one embodiment, the PHY processor 170 is configured to down-convert one or more RF signals received via one or more antennas 178 into one or more baseband analog signals, and convert the (multiple) analog baseband signals into one or more digital baseband signals. The PHY processor 170 is further configured to process one or more digital baseband signals to demodulate one or more digital baseband signals and generate a PPDU. The PHY processor 170 includes amplifiers (e.g., LNA, power amplifier, etc.), RF down-converters, RF up-converters, multiple filters, one or more ADCs, one or more DACs, one or more DFT calculators (e.g., FFT calculator), one or more IDFT calculators (e.g., IFFT calculator), one or more modulators, one or more demodulators, etc.

[0040] The PHY processor 170 is configured to generate one or more RF signals, which are provided to one or more antennas 178. The PHY processor 170 is further configured to receive one or more RF signals from one or more antennas 178.

[0041] According to some embodiments, the MAC processor 166 is configured to control the PHY processor 170 to generate one or more RF signals, for example, by providing one or more MAC layer data units (e.g., MPDU) to the PHY processor 170 and optionally providing one or more control signals to the PHY processor 170. In one embodiment, the MAC processor 166 includes a processor configured to execute machine-readable instructions stored in a memory device (not shown) such as RAM, ROM, flash memory, etc. In one embodiment, the MAC processor 166 includes a hardware state machine.

[0042] In some embodiments, the MAC processor 166 includes a multi-channel segment transmission controller (not shown) that is the same as or similar to the multi-channel segment transmission controller 142 of the AP 114. For example, according to some embodiments, the client station 154-1 is configured to transmit synchronously (e.g., start transmission at the same start time) in different channel segments in some scenarios, and transmit asynchronously (e.g., transmission does not need to start at the same start time) in different channel segments in other scenarios.

[0043] In one embodiment, each of the client stations 154-2 and 154-3 has the same or similar structure as the client station 154-1. Each of the client stations 154-2 and 154-3 has the same or different numbers of transceivers and antennas. For example, according to one embodiment, each of the client stations 154-2 and / or client station 154-3 has only two transceivers and two antennas (not shown).

[0044] In one embodiment, multiple different frequency bands within the RF spectrum are used for signal transmission within WLAN 110. In one embodiment, different communication devices (i.e., AP 114 and client stations 154) can be configured for operation in different frequency bands. In one embodiment, at least some communication devices within WLAN 110 (e.g., AP 114 and client stations 154) can be configured for operation on multiple different frequency bands. Exemplary frequency bands include a first frequency band (“2 GHz band”) corresponding to a frequency range of approximately 2.4 GHz - 2.5 GHz of the RF spectrum, and a second frequency band (“5 GHz band”) corresponding to a frequency range of approximately 5 GHz - 5.9 GHz. In one embodiment, one or more communication devices within the WLAN can also be configured for operation in a third frequency band (“6 GHz band”) within the range of 6 GHz - 7 GHz. As described above, each frequency band includes multiple component channels that can be combined within the corresponding frequency band to generate a wider bandwidth channel. In embodiments corresponding to multi-channel segment operation on a first channel segment and a second channel segment, the first channel segment and the second channel segment can be in different frequency bands or within the same frequency band. In some embodiments, at least one communication device within WLAN 110 (e.g., at least AP 114) is configured for simultaneous operation on any two of the 2 GHz band, 5 GHz band, and 7 GHz band. In some embodiments, at least one communication device within WLAN 110 (e.g., at least AP 114) is configured for simultaneous operation on all three of the 2 GHz band, 5 GHz band, and 7 GHz band.

[0045] Figure 2A FIG. is an example synchronous transmission 200 on different channel segments according to an embodiment. In one embodiment, transmission 200 is generated and transmitted by network interface device 122( Figure 1 ) to one or more client stations 154 (e.g., client station 154-1). In another embodiment, transmission 200 is generated and transmitted by network interface device 162( Figure 1 ) to AP114.

[0046] In one embodiment, transmission 200 corresponds to a single-user (SU) transmission that is generated and transmitted to a single communication device. In another embodiment, transmission 200 corresponds to a multi-user (MU) transmission that includes data of multiple communication devices (e.g., multiple client stations 154). For example, in one embodiment, MU transmission 200 is an OFDMA transmission. In another embodiment, MU transmission 200 is a MU-MIMO transmission.

[0047] Transmission 200 includes a first RF signal 204 in a first channel segment 208 and a second RF signal 212 in a second channel segment 216. According to one embodiment, the first RF signal 204 corresponds to a first PPDU and the second RF signal 212 corresponds to a second PPDU. The first signal includes a PHY preamble 220 and a PHY data portion 224. The second signal 212 includes a PHY preamble 228, a data portion 232, and an optional padding 236. Transmission 200 is synchronized such that the transmissions of the first signal 204 and the second signal 212 start at the same time t1. In some embodiments, the first signal 204 and the second signal 212 also end at the same time t2.

[0048] In some embodiments, the PHY preamble 220 and the PHY preamble 228 do not need to have the same duration and / or end at the same time. In other embodiments, the PHY preamble 220 and the PHY preamble 228 need to have the same duration and / or end at the same time.

[0049] In an embodiment where the second RF signal 212 will have a shorter duration than the first RF signal 204, the PHY data portion 232 is appended with a packet extension field 236 such that the transmission of the signal 212 ends at t2. In one embodiment, the packet extension field 236 includes any data that is ignored by the receiver.

[0050] In another embodiment where the second RF signal 212 has a shorter duration than the first RF signal 204, the duration information in the MAC header (not shown) within the PHY data portion 232 is set to indicate that the transmission of the signal 212 ends at t2, which causes another communication device to set the network allocation vector (NAV) timer of another communication device to a value indicating that the transmission of the signal 212 will end at t2.

[0051] In another embodiment where the second RF signal 212 will have a shorter duration than the first RF signal 204, padding information is included in the PHY data portion 232 such that the transmission of the signal 212 ends at t2.

[0052] Example formats of the PHY preamble 220 and the PHY preamble 228 are described in more detail below. In one embodiment, at least a portion of the PHY preamble 220 and at least a portion of the PHY preamble 228 include different information. In another embodiment, at least a portion of the PHY preamble 220 and at least a portion of the PHY preamble 228 have the same structure and / or include the same information. In some embodiments, at least a portion of the PHY preamble 220 and at least a portion of the PHY preamble 228 are the same.

[0053] In embodiments where the first channel segment 208 includes multiple component channels (e.g., 20 MHz sub-channels), at least a portion (e.g., the legacy portion) of the PHY preamble 220 is generated by generating a field corresponding to one component channel and replicating the field on one or more other component channels corresponding to the first channel segment 208. In embodiments where the second channel segment 216 includes multiple component channels (e.g., 20 MHz sub-channels), at least a portion (e.g., the legacy portion) of the PHY preamble 228 is generated by generating a field corresponding to one component channel and replicating the field on one or more other component channels corresponding to the second channel segment 216.

[0054] In various embodiments, the first channel segment 208 and the second channel segment 216 are in different RF bands or are co-located in the same RF band. In one embodiment, the (multiple) RF bands correspond to the 2 GHz band, the 5 GHz band, and the 6 GHz band, as described above. Each of the first channel segment 208 and the second channel segment 216 may include one or more component channels. In one embodiment, the frequency bandwidth of the first channel segment 208 (i.e., the frequency bandwidth of the first signal 204) is different from the frequency bandwidth of the second channel segment 216 (i.e., the frequency bandwidth of the second signal 212). In another embodiment, the frequency bandwidth of the first channel segment 208 is the same as the frequency bandwidth of the second channel segment 216.

[0055] In one embodiment, the first channel segment 208 and the second channel segment 216 are frequency-separated. For example, there is a frequency gap between the first channel segment 208 and the second channel segment 216. In various embodiments, the gap is at least 500 kHz, at least 1 MHz, at least 5 MHz, at least 20 MHz, etc.

[0056] In some embodiments, the first signal 204 is transmitted via a first number of spatial streams or space-time streams (hereinafter referred to as "spatial streams" for brevity), and the second signal 212 is transmitted via a second number of spatial streams different from the first number of spatial streams. In such an embodiment, the PHY preamble 220 includes a first number of LTFs corresponding to the first number of spatial streams, and the PHY preamble 228 includes a second number of LTFs (different from the first number of LTFs) corresponding to the second number of spatial streams. In such another embodiment, the PHY preamble 220 and the PHY preamble 228 include the same number of LTFs, even when the first signal 204 is transmitted via a first number of spatial streams and the second signal 212 is transmitted via a second number of spatial streams different from the first number of spatial streams. In one embodiment, the same number of LTFs corresponds to the one of the first signal 204 and the second signal 212 that has the larger number of spatial streams. In other embodiments, the first signal 204 and the second signal 212 are transmitted via the same number of spatial streams.

[0057] In one embodiment, at least the PHY data portion 224 and at least the PHY data portion 232 employ different coding schemes and / or modulation schemes. For example, in one embodiment, the PHY data portion 224 is generated using a first MCS, while the PHY data portion 432 is generated using a different second MCS. In other embodiments, the PHY data portion 224 and the PHY data portion 232 are generated using the same MCS.

[0058] In one embodiment, the transmission 200 corresponds to a single PPDU, where a first frequency portion of the single PPDU is transmitted via the first channel 208, and a second frequency portion of the single PPDU is transmitted via the second channel 216. In another embodiment, the first signal 204 corresponds to a first PPDU, while the second signal 212 corresponds to a second PPDU. In one embodiment, each of the PHY preambles 220 and 228, and the PHY data portions 224 and 232 are composed of one or more OFDM symbols.

[0059] Figure 2B is a diagram of an example asynchronous transmission 250 over different channel segments according to an embodiment. In one embodiment, the transmission 250 is generated and transmitted by the network interface device 122 ( Figure 1 ) to one or more client stations 154 (e.g., client station 154-1). In another embodiment, the transmission 250 is generated and transmitted by the network interface device 162 ( Figure 1 ) to the AP 114.

[0060] The asynchronous transmission 250 is similar to Figure 2AThe synchronous transmission 200, and for the sake of brevity, elements with the same number are not described in detail. Different from Figure 2A the synchronous transmission 200, the transmission of the signal 204 and the transmission of the signal 212 start at different times. In addition, according to some embodiments, the transmission of the signal 204 and the transmission of the signal 212 end at different times. In addition, according to some embodiments, the signal 212 does not include Figure 2A the packet extension field 236.

[0061] Now refer to Figure 1 and Figures 2A to 2B , according to some embodiments, a communication device (e.g., AP 114, client station 154-1, etc.) is configured to generate and transmit synchronous transmissions such as transmission 200 ( Figure 2A ) at some times (and / or in some scenarios), and generate and transmit asynchronous transmissions such as transmission 250 ( Figure 2B ) at other times (and / or in other scenarios). For example, at least in some embodiments, transmitting asynchronous transmissions in different channel segments does not require the different channel segments to be idle simultaneously, thus allowing the simultaneous use of different channel segments at least in some embodiments and / or scenarios when synchronous transmission may not be possible (e.g., when synchronous transmission requires different channel segments to be idle simultaneously). On the other hand, in some scenarios, asynchronous transmissions in different channel segments may not be allowed, at least in some embodiments and / or scenarios, such as when the different channel segments are relatively close in frequency.

[0062] Figure 3A is a diagram of an example synchronous downlink MU OFDMA transmission 300 on different channel segments according to an embodiment. In one embodiment, the transmission 300 is generated and transmitted by the network interface device 122 ( Figure 1 ) to multiple client stations 154.

[0063] The OFDMA transmission 300 includes a first RF signal 304 in a first channel segment 308 and a second RF signal 312 in a second channel segment 316. In various embodiments, the first channel segment 308 and the second channel segment 316 are respectively similar to the first channel segment 208 and the second channel segment 216 as described above with reference to Figure 2A . The transmission 300 is synchronized such that the first RF signal 304 and the second RF signal 312 start at the same time t1. In some embodiments, the first RF signal 304 and the second RF signal 312 end at the same time t2.

[0064] The first signal 304 includes a PHY preamble 320 and a PHY data portion 324. The second signal 312 includes a PHY preamble 328 and a data portion 332. In some embodiments, the PHY preamble 320 and the PHY preamble 328 do not need to have the same duration and / or end at the same time. In other embodiments, the PHY preamble 320 and the PHY preamble 328 need to have the same duration and / or end at the same time.

[0065] In an embodiment where the second RF signal 312 would otherwise have a shorter duration than the first RF signal 304, a packet extension field 336 is appended to the PHY data portion 332 such that the transmission of the signal 312 ends at t2. In one embodiment, the packet extension field 336 includes any data that is ignored by the receiver.

[0066] In another embodiment where the second RF signal 312 has a shorter duration than the first RF signal 304, the duration information in the MAC header (not shown) within the PHY data portion 332 is set to indicate that the transmission of the signal 312 ends at t2, which causes another communication device to set its NAV timer to a value indicating that the transmission of the signal 212 will end at t2.

[0067] In another embodiment where the second RF signal 312 would have a shorter duration than the first RF signal 304, padding information is included in the PHY data portion 332 such that the transmission of the signal 312 ends at t2.

[0068] In one embodiment, the PHY preamble 320 and the PHY preamble 328 are formatted in a manner similar to the PHY preamble 204. Example formats of the PHY preamble 320 and the PHY preamble 328 are described in more detail below. In one embodiment, at least a portion of the PHY preamble 320 and at least a portion of the PHY preamble 328 include different information. In another embodiment, at least a portion of the PHY preamble 320 and at least a portion of the PHY preamble 328 have the same structure and / or include the same information. In some embodiments, at least a portion of the PHY preamble 320 and at least a portion of the PHY preamble 328 are the same.

[0069] In embodiments where the first channel segment 308 includes a plurality of component channels (e.g., 20 MHz sub-channels), at least a portion (e.g., the legacy portion) of the PHY preamble 320 is generated by generating a field corresponding to one component channel and replicating the field on one or more other component channels corresponding to the first channel segment 308. In embodiments where the second channel segment 316 includes a plurality of component channels, at least a portion (e.g., the legacy portion) of the PHY preamble 328 is generated by generating a field corresponding to one component channel and replicating the field on one or more other component channels corresponding to the second channel segment 316.

[0070] In various embodiments, the first channel segment 308 and the second channel segment 316 are in different RF bands or are co-located in the same RF band. In one embodiment, the (one or more) RF bands correspond to the 2 GHz band, the 5 GHz band, and the 6 GHz band, as described above. Each of the first channel segment 308 and the second channel segment 316 may include one or more component channels. In one embodiment, the frequency bandwidth of the first channel segment 308 (i.e., the frequency bandwidth of the first signal 304) is different from the frequency bandwidth of the second channel segment 316 (i.e., the frequency bandwidth of the second signal 212). In another embodiment, the frequency bandwidth of the first channel segment 308 is the same as the frequency bandwidth of the second channel segment 316.

[0071] In one embodiment, the first communication channel 308 and the second communication channel 316 are separated in frequency. For example, there is a frequency gap between the first communication channel 308 and the second communication channel 316. In various embodiments, the gap is at least 500 kHz, at least 1 MHz, at least 5 MHz, at least 20 MHz, etc.

[0072] In some embodiments, the first signal 304 is transmitted via a first number of spatial streams, and the second signal 312 is transmitted via a second number of spatial streams different from the first number of spatial streams. In such an embodiment, the PHY preamble 320 includes a first number of LTFs corresponding to the first number of spatial streams, and the PHY preamble 328 includes a second number of LTFs (different from the first number of LTFs) corresponding to the second number of spatial streams. In such another embodiment, the PHY preamble 320 and the PHY preamble 328 include the same number of LTFs, even when the first signal 304 is transmitted via a first number of spatial streams and the second signal 312 is transmitted via a second number of spatial streams different from the first number of spatial streams. In one embodiment, the same number of LTFs corresponds to the one of the first signal 304 and the second signal 312 that has the larger number of spatial streams. In other embodiments, the first signal 304 and the second signal 312 are transmitted via the same number of spatial streams.

[0073] In one embodiment, at least the PHY data section 324 and at least the PHY data section 332 employ different coding schemes and / or modulation schemes.

[0074] In one embodiment, the transmission 300 corresponds to a single PPDU, where a first frequency portion of the single PPDU is transmitted via a first channel 308 and a second frequency portion of the single PPDU is transmitted via a second channel 316. In another embodiment, the first signal 304 corresponds to a first PPDU and the second signal 312 corresponds to a second PPDU. In one embodiment, each of the PHY preambles 320 and 328, and the PHY data sections 324 and 332, are composed of one or more OFDM symbols.

[0075] The PHY data section 324 and the PHY data section 332 include respective frequency-division multiplexed data for respective client stations 154. Individual data within the data section 324 is transmitted to a corresponding client station 154 in a corresponding allocated frequency resource unit (RU) 340. Individual data within the data section 332 is transmitted to a corresponding client station 154 in a corresponding allocated RU 344. In various embodiments, the transmission signals corresponding to some or all of the RUs 340 / 344 use different coding schemes and / or modulation schemes. For example, the transmission signals corresponding to RU 340-1 and RU 344-1 are generated using different MCSs and / or different numbers of spatial streams / spatio-temporal streams, etc. In an embodiment where the duration of the data in RU 344 is shorter than the duration of the PHY data section 324, padding is added to the data in RU 344 to ensure that the durations of the PHY data sections in the two communication channels are the same.

[0076] In at least some embodiments, at least some of the client stations 154 are configured to operate in only one RF band. In such an embodiment, RUs are allocated to client stations 154 that are configured to operate only within the RF band. As an illustrative example, STA2 and STA3 are configured to operate only in the first RF band. Thus, in one embodiment, the data corresponding to STA2 and STA3 is transmitted on RUs within the first channel segment 308, which is within the first RF band. Similarly, STA4 is configured to operate only in the second RF band. Thus, in one embodiment, the data corresponding to STA4 is transmitted on RUs within the second channel segment 316, which is within the second RF band. On the other hand, STA1 is configured to operate in both the first RF band and the second RF band. Thus, the data corresponding to STA1 can be transmitted on RUs located in one or both of the first channel segment 308 and the second channel segment 316.

[0077] Figure 3B is a diagram of an example asynchronous MU OFDMA transmission 350 over different channel segments according to an embodiment. In one embodiment, the transmission 350 is generated and transmitted by the network interface device 122( Figure 1 ) to one or more client stations 154 (e.g., client station 154-1). In another embodiment, the transmission 350 is generated and transmitted by the network interface device 162( Figure 1 ).

[0078] The asynchronous transmission 350 is similar to Figure 2A the synchronous transmission 300, and for the sake of brevity, elements with the same number are not described in detail. Different from Figure 3A the synchronous transmission 300, the transmission of signal 304 and the transmission of signal 312 start at different times. In addition, according to some embodiments, the transmission of signal 304 and the transmission of signal 312 end at different times. In addition, according to some embodiments, signal 312 does not include Figure 3A the packet extension field 336 of

[0079] Now referring to Figure 1 and Figures 3A to 3B , according to some embodiments, a communication device (e.g., AP 114, client station 154-1, etc.) is configured to generate and transmit synchronous transmissions such as transmission 300( Figure 3A ) at some times (and / or in some scenarios), and generate and transmit asynchronous transmissions such as transmission 350( Figure 3B ) at other times (and / or in other scenarios).

[0080] Figure 4 is a flowchart of an example method 400 for transmission via multiple frequency segments in a wireless communication network according to an embodiment. According to some embodiments, Figure 1 the AP 114 of Figure 1 is configured to implement method 400. According to other embodiments,

[0081] At block 404, a communication device determines (e.g., AP 114 determines, network interface 122 determines, MAC processor 126 determines, multi-channel segment transmission controller 142 determines, etc.) whether simultaneous corresponding transmissions in a plurality of frequency bands are to be synchronized (e.g., whether the simultaneous corresponding transmissions are to start at the same time). In various embodiments, the plurality of frequency bands are contiguous in frequency, or pairs of one or more adjacent frequency bands are separated in frequency by respective frequency gaps. In various embodiments, each frequency band of the plurality of frequency bands spans the same frequency bandwidth, or the frequency bands of the plurality of frequency bands span different frequency bandwidths. In various embodiments, two or more of the plurality of frequency bands are in the same RF band (e.g., 2 GHz band, 5 GHz band, 6 GHz band, etc.), or two or more of the plurality of frequency bands are in different RF bands.

[0082] In various embodiments, determining whether simultaneous corresponding transmissions are to be synchronized at block 404 is based on various parameters and / or factors. For example, in one embodiment, determining whether simultaneous corresponding transmissions are to be synchronized at block 404 is based on the bandwidth of the frequency gap between adjacent frequency bands of the plurality of frequency bands. For example, according to an illustrative embodiment, when the frequency gap between a first frequency band and a second frequency band is less than a threshold, the communication device determines (e.g., AP 114 determines, network interface 122 determines, MAC processor 126 determines, etc.) at block 404 that the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized (e.g., the simultaneous corresponding transmissions are to start at the same time); and when the frequency gap between the first frequency band and the second frequency band is greater than the threshold, the communication device determines (e.g., AP 114 determines, network interface 122 determines, MAC processor 126 determines, etc.) at block 404 that the simultaneous transmissions in the first frequency band and the second frequency band are not to be synchronized. According to an illustrative embodiment, when the first frequency band and the second frequency band are relatively close in frequency (e.g., the frequency gap between the first frequency band and the second frequency band is less than the threshold), the amount (or probability) of inter-channel interference is relatively high, and thus synchronized transmissions are required to improve performance (e.g., total throughput); while when the first frequency band and the second frequency band are relatively far apart in frequency (e.g., the frequency gap between the first frequency band and the second frequency band is greater than the threshold), the amount (or probability) of inter-channel interference is relatively low, and thus synchronized transmissions are not required.

[0083] As another example, in another embodiment, additionally or alternatively, determining at block 404 whether simultaneous corresponding transmissions are to be synchronized is based on the bandwidth capabilities of one or more other communication devices that are to receive the simultaneous corresponding transmissions. For example, according to an illustrative embodiment, in response to the AP 114 determining (e.g., the network interface 122 determines, the MAC processor 126 determines, etc.) that one or more other communication devices cannot receive an asynchronous transmission, the AP 114 determines at block 404 that the simultaneous corresponding transmissions in multiple frequency bands are to be synchronized.

[0084] As another example, determining at block 404 whether simultaneous corresponding transmissions are to be synchronized is based on the total frequency bandwidth of the multiple frequency bands among the multiple frequency bands. For example, according to an illustrative embodiment, when the total bandwidth is less than a threshold, the communication device determines at block 404 (e.g., the AP 114 determines, the network interface 122 determines, the MAC processor 126 determines, etc.) that the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized (e.g., the simultaneous corresponding transmissions are to start at the same time); while when the total bandwidth is greater than the threshold, the communication device determines at block 404 (e.g., the AP 114 determines, the network interface 122 determines, the MAC processor 126 determines, etc.) that the simultaneous transmissions in the first frequency band and the second frequency band are not to be synchronized. According to an illustrative embodiment, when the total bandwidth is relatively narrow (e.g., the total bandwidth is less than the threshold), the probability of finding a time when all frequency bands among the multiple frequency bands are idle is relatively high, and the benefits of synchronous transmissions can improve performance (e.g., total throughput); while when the total bandwidth is relatively wide (e.g., the total bandwidth is greater than the threshold), the probability of finding a time when all frequency bands among the multiple frequency bands are idle is relatively low, and the benefits of synchronous transmissions do not exceed the performance degradation caused by an increased failure due to finding a time when all frequency bands are idle.

[0085] When it is determined at block 404 that the simultaneous corresponding transmissions in multiple frequency bands are to be synchronized, the process proceeds to block 408. At block 408, the AP 114 transmits simultaneously via multiple frequency bands in a synchronized manner (e.g., the network interface device 122 transmits simultaneously, the PHY processor 130 transmits simultaneously, etc.). According to one embodiment, transmitting simultaneously at block 408 includes transmitting a first signal via a first frequency band at a first time and transmitting a second signal via a second frequency band at the first time.

[0086] In some embodiments, before simultaneous transmission at block 408 in a synchronous manner, AP 114 determines (e.g., network interface device 122 determines, MAC processor 126 determines, etc.) when multiple frequency bands are simultaneously idle, and after determining that the multiple frequency bands are simultaneously idle, begins simultaneous synchronous transmission at block 408. In some embodiments, before simultaneous transmission at block 408 in a synchronous manner, AP 114 waits (e.g., network interface device 122 waits, MAC processor 126 waits, etc.) until the multiple frequency bands are determined to be simultaneously idle, and then begins simultaneous synchronous transmission at block 408.

[0087] In some embodiments, the simultaneous transmission at block 408 includes transmitting signals such as those described above with reference to Figure 2A the description. In other embodiments, the simultaneous transmission at block 408 includes transmitting signals such as those described above with reference to Figure 3A the description. In other embodiments, the simultaneous transmission at block 408 includes transmitting other suitable signals having other suitable formats.

[0088] In some embodiments, the simultaneous transmission at block 408 includes: the multi-channel segment transmission controller 142 prompting the PHY processor 130 to begin a first transmission in a first frequency band at a first time and a second transmission in a second frequency band at the first time.

[0089] On the other hand, when it is determined at block 404 that the simultaneous corresponding transmissions in the multiple frequency bands are to be asynchronous, the process proceeds to block 412. According to one embodiment, the simultaneous transmission at block 412 includes: transmitting a third signal via a third time period at a second time and transmitting a fourth signal via a fourth frequency band at a third time. In some embodiments, according to one embodiment, the third frequency band is the first frequency band (block 408), and the fourth frequency band is the second frequency band (block 408).

[0090] In some embodiments, different from the synchronous transmission at block 408, before the transmission in one of the frequency segments at block 412 can start, AP 114 does not need to determine when multiple frequency segments are simultaneously idle or wait for the multiple frequency segments to be simultaneously idle for a period of time. For example, according to one embodiment, when AP 114 determines (e.g., network interface device 122 determines, MAC processor 126 determines, etc.) that a first frequency segment among multiple frequency segments is idle, AP 114 can start transmitting in the first frequency segment (at block 412), even if AP 114 determines (e.g., network interface device 122 determines, MAC processor 126 determines, etc.) that a second frequency segment among the multiple frequency segments is not simultaneously idle. When AP 114 later determines that the second frequency segment has also become idle, AP 114 can start transmitting in the second frequency segment (at block 412) simultaneously with the transmission in the first frequency segment (at block 412).

[0091] In some embodiments, the simultaneous transmission at block 412 includes transmitting signals such as those described above with reference to Figure 2B In other embodiments, the simultaneous transmission at block 412 includes transmitting signals such as those described above with reference to Figure 3B In other embodiments, the simultaneous transmission at block 412 includes transmitting other suitable signals with other suitable formats.

[0092] In some embodiments, the simultaneous transmission at block 412 includes: the multi-channel segment transmission controller 142 prompting the PHY processor 130 to start a third transmission in a third frequency segment at a second time and start a fourth transmission in a fourth frequency segment at a third time.

[0093] In some embodiments, the first frequency segment is the same as the third frequency segment, and the second frequency segment is the same as the fourth frequency segment. In other embodiments, the first frequency segment is different from the third frequency segment, and / or the second frequency segment is different from the fourth frequency segment.

[0094] In some embodiments, the first packet is the same as the third packet, and the second packet is the same as the fourth packet. In other embodiments, the first packet is different from the third packet, and / or the second packet is different from the fourth packet.

[0095] Figure 5 FIG. is a diagram of an example network interface device 500 configured for multi-channel segment operation according to an embodiment. For example, in one embodiment, network interface device 500 is configured for synchronous and / or asynchronous transmission / reception on multiple frequency segments. In one embodiment, network interface device 500 corresponds to Figure 1 the network interface device 122 of AP 114. In another embodiment, network interface device 500 corresponds to Figure 1The network interface device 162 of client station 154-1.

[0096] The network interface device 500 is configured for operation on two frequency bands. The network interface device 500 includes a MAC processor 508 coupled to a PHY processor 516. The MAC processor 508 exchanges frames (or PSDUs) with the PHY processor 516.

[0097] In one embodiment, the MAC processor 508 corresponds to Figure 1 the MAC processor 126. In another embodiment, the MAC processor 508 corresponds to Figure 1 the MAC processor 166. In one embodiment, the PHY processor 516 corresponds to the Figure 1 PHY processor 130. In another embodiment, the PHY processor 516 corresponds to Figure 1 the PHY processor 170.

[0098] The PHY processor 516 includes a single baseband signal processor 520. The single baseband signal processor 520 is coupled to a first RF radio (Radio-1) 528 and a second RF radio (Radio-2) 536. In one embodiment, the RF radio 528 and the RF radio 536 correspond to Figure 1 the transceiver 134. In another embodiment, the RF radio 528 and the RF radio 536 correspond to Figure 1 the transceiver 174. In one embodiment, the RF radio 528 is configured to operate on a first RF band, and the RF radio 536 is configured to operate on a second RF band. In another embodiment, both the RF radio 528 and the RF radio 536 are configured to operate on the same RF band.

[0099] In one embodiment, the MAC processor 508 generates data corresponding to MAC layer data units (e.g., frames), and provides these frames (or PSDUs) to the baseband signal processor 520. The baseband signal processor 520 is configured to receive frames (or PSDUs) from the MAC processor 508, encapsulate the frames (or PSDUs) into corresponding packets and generate corresponding baseband signals corresponding to the corresponding packets. The baseband signal processor 520 provides the corresponding baseband signals to Radio-1 528 and Radio-2 536. Radio-1 528 and Radio-2 536 up-convert the corresponding baseband signals to generate corresponding RF signals for transmission via the first frequency band and the second frequency band respectively. Radio-1 528 transmits the first RF signal via the first frequency band, and Radio-2 536 transmits the second RF signal via the second frequency band.

[0100] In some embodiments, the MAC processor 508 determines whether a frame is to be transmitted synchronously or asynchronously, and notifies the baseband signal processor 520 whether the frame is to be transmitted synchronously or asynchronously when providing the frame to the baseband signal processor 520. In some embodiments, the MAC processor 508 determines in which frequency band the frame is to be transmitted, and notifies the baseband signal processor 520 of the frequency band in which the frame is to be transmitted when providing the frame to the baseband signal processor 520.

[0101] When the first RF signal and the second RF signal are to be synchronized, the baseband signal processor 520 is configured to ensure that the corresponding transmission signals on the first frequency band and the second frequency band are synchronized. For example, the baseband signal processor 520 starts providing the corresponding baseband signals to Radio-1 528 and Radio-2 536 at the same time.

[0102] Radio-1 528 and Radio-2 536 are also configured to receive the corresponding RF signals via the first frequency band and the second frequency band respectively. Radio-1 528 and Radio-2 536 generate the corresponding baseband signals corresponding to the corresponding received signals. The generated corresponding baseband signals are provided to the baseband signal processor 520. The baseband signal processor 520 generates the corresponding PSDUs corresponding to the corresponding received signals, and provides the PSDUs to the MAC processor 508. The MAC processor 508 processes the PSDUs received from the baseband signal processor 520.

[0103] Figure 6A FIG. is a diagram of example PPDUs 604 and 608 transmitted in corresponding frequency bands. For example, PPDU 604 is transmitted in the first frequency band, and PPDU 608 is transmitted in the second frequency band. In some embodiments and / or scenarios, the first frequency band is separated from the second frequency band by a frequency gap in frequency. In other embodiments and / or scenarios, the first frequency band is adjacent to the second frequency band in frequency, and the first frequency band is not separated from the second frequency band in frequency.

[0104] In some embodiments, the PHY processor 130 ( Figure 1 ) is configured to generate and transmit PPDUs 604 and 608. In some embodiments, the PHY processor 170 ( Figure 1 ) is configured to generate and transmit PPDUs 604 and 608. In some embodiments, the baseband processor 520 ( Figure 5 ) is configured to generate PPDUs 604 and 608, and the radio devices 528, 536 ( Figure 5 ) are configured to transmit PPDUs 604 and 608.

[0105] PPDU 604 includes a legacy PHY preamble 612 (sometimes referred to as legacy preamble 612), a non-legacy PHY preamble (e.g., EHT preamble) 616, and a PHY data portion 620. The legacy preamble 612 includes a legacy short training field (L-STF) 624, a legacy long training field (L-LTF) 628, and a legacy signal field (L-SIG) 632. The L-SIG 632 includes a rate subfield (not shown) and a length subfield (not shown) that jointly indicate the duration of the PPDU 604. In some embodiments, the EHT preamble 616 includes PHY parameters regarding the PPDU 604 that are used by a receiver device to correctly process the PPDU 604, such as a modulation and coding scheme (MCS) subfield indicating the MCS for the PHY data portion 620. When the PPDU 604 is a MU PPDU, the EHT preamble 616 includes allocation information indicating frequency resource unit (RU) allocation information, spatial stream allocation information, etc. In some embodiments, the EHT preamble 616 includes one or more long training fields, and the number of long training fields depends on the number of spatial streams used to transmit the PHY data portion 620.

[0106] PPDU 608 includes a legacy preamble 642, a non-legacy PHY preamble (e.g., EHT preamble) 646, and a PHY data portion 650. The legacy preamble 642 includes an L-STF 654, an L-LTF 658, and an L-SIG 632. The L-SIG 632 includes a rate subfield (not shown) and a length subfield (not shown) that jointly indicate the duration of the PPDU 608. In some embodiments, the EHT preamble 646 includes PHY parameters regarding the PPDU 608 that are used by a receiver device to correctly process the PPDU 608, such as an MCS subfield indicating the MCS for the PHY data portion 650. When the PPDU 608 is a MU PPDU, the EHT preamble 646 includes allocation information indicating frequency RU allocation information, spatial stream allocation information, etc. In some embodiments, the EHT preamble 646 includes one or more long training fields, and the number of long training fields depends on the number of spatial streams used to transmit the PHY data portion 650.

[0107] In some embodiments in which the transmissions of PPDU 604 and PPDU 608 are synchronized, PPDU 608 includes a packet extension field 668 such that the duration of PPDU 608 is the same as the duration of PPDU 604. In some embodiments, the PHY data portion 650 additionally or alternatively includes padding as described above. In other embodiments, signal extension is additionally or alternatively used for PPDU 608 such that the receiver device sets its NAV counter to a value indicating a duration corresponding to the duration of PPDU 604 as described above. In some embodiments in which the transmissions of PPDU 604 and PPDU 608 are asynchronous, PPDU 608 does not include the packet extension field 668.

[0108] In some embodiments, the duration of EHT preamble 616 is different from (or does not need to be the same as) the duration of EHT preamble 646. In other embodiments, the duration of EHT preamble 616 needs to be the same as the duration of EHT preamble 646 (e.g., padding bits are added (if needed) to EHT preamble 646 such that the duration of EHT preamble 646 is the same as the duration of EHT preamble 616).

[0109] In embodiments in which PPDU 604 has a different duration from PPDU 608, L-SIG 632 includes different information from L-SIG 662. For example, the length subfield in L-SIG 632 indicates a different length from the length subfield in L-SIG 662.

[0110] Figure 6B is a diagram of an example non-legacy preamble 674 (e.g., an EHT preamble) that serves as non-legacy preamble 616 or non-legacy preamble 646 according to some embodiments.

[0111] In some embodiments, PHY processor 130 ( Figure 1 ) is configured to generate non-legacy preamble 674. In some embodiments, PHY processor 170 ( Figure 1 ) is configured to generate non-legacy preamble 674. In some embodiments, baseband processor 520 ( Figure 5 ) is configured to generate non-legacy preamble 674.

[0112] The non-legacy preamble 674 includes a first signal field (EHT-SIGA) 678, a second signal field (EHT-SIGB) 682, a short training field (EHT-STF) 686, and one or more long training fields (EHT-LTF) 690. In one embodiment, when the PHY data portion corresponding to the non-legacy preamble 674 is to be transmitted via n spatial streams (where n is a suitable positive integer), the non-legacy preamble 674 includes no more than n EHT-LTFs 690. In another embodiment, when the PHY data portion corresponding to the non-legacy preamble 674 is transmitted via n spatial streams, the non-legacy preamble 674 includes at least n EHT-LTFs 690.

[0113] In some embodiments, for MU PPDU, EHT-SIGB 682 is included, while for single-user (SU) PPDU, EHT-SIGB 682 is not included.

[0114] In various embodiments, EHT-SIGA 678 and / or EHT-SIGB 682 indicate the MCS (or multiple MCSs for MU PPDU) for the PHY data portion corresponding to the non-legacy preamble 674. Thus, when different MCSs are used for different frequency bands, the content of EHT-SIGA 678 in different frequency bands is different.

[0115] Similarly, at least in some embodiments, when different numbers of spatial streams are used for different frequency bands, the number of EHT-LTFs 690 in different frequency bands is different.

[0116] Now referring to Figures 6A to 6B , in embodiments where L-SIG 632 and L-SIG 662 include different information, a copy of L-SIG 632 is transmitted in each subchannel (e.g., each 20 MHz subchannel) of the first frequency band, and a copy of L-SIG 662 is transmitted in each subchannel (e.g., each 20 MHz subchannel) of the second frequency band. In embodiments where one or more subchannels in the frequency band are punctured (e.g., not used for transmission), a copy of L-SIG 632 / 662 is not transmitted in the punctured subchannels.

[0117] In embodiments where the non-legacy signal field 678 includes different information in different frequency bands, a copy of the non-legacy signal field 678 including the information of the first frequency band is transmitted in each subchannel (e.g., each 20 MHz subchannel) of the first frequency band, and a copy of the non-legacy signal field 678 including the information of the second frequency band is transmitted in each subchannel (e.g., each 20 MHz subchannel) of the second frequency band. In embodiments where one or more subchannels in a frequency band are punctured (e.g., not used for transmission), a copy of the non-legacy signal field 678 is not transmitted in the punctured subchannels.

[0118] Similarly, in embodiments where the non-legacy signal field 682 includes different information in different frequency bands, a copy of the non-legacy signal field 682 including the information of the first frequency band is transmitted in each subchannel (e.g., each 20 MHz subchannel) of the first frequency band, and a copy of the non-legacy signal field 682 including the information of the second frequency band is transmitted in each subchannel (e.g., each 20 MHz subchannel) of the second frequency band. In embodiments where one or more subchannels in a frequency band are punctured (e.g., not used for transmission), a copy of the non-legacy signal field 682 is not transmitted in the punctured subchannels.

[0119] In some embodiments (e.g., where PPDU 604 is a MU PPDU and PPDU 608 is a SU PPDU), a copy of the non-legacy signal field 682 including the information of the first frequency band is transmitted in each subchannel (e.g., each 20 MHz subchannel) of the first frequency band, and the non-legacy signal field 682 is not transmitted in the second frequency band.

[0120] In some embodiments, the non-legacy signal field 678 includes a bandwidth subfield 694 that indicates the total bandwidth of only the frequency band in which the PPDU 604 / 608 is transmitted. For example, when PPDU 604 is transmitted in a first frequency band with a total bandwidth of 160 MHz and PPDU 608 is transmitted in a second frequency band with a total bandwidth of 40 MHz, the bandwidth subfield 694 in PPDU 604 indicates a bandwidth of 160 MHz, while the bandwidth subfield 694 in PPDU 608 indicates a bandwidth of 40 MHz.

[0121] In some embodiments, the non-legacy signal field 678 includes a frequency band identifier (ID) subfield 698 that indicates the frequency band in which the PPDU 604 / 608 is transmitted. For example, when PPDU 604 is transmitted in the first frequency band and PPDU 608 is transmitted in the second frequency band, the frequency band ID subfield 698 in PPDU 604 indicates the first frequency band, while the frequency band ID subfield 698 in PPDU 608 indicates the second frequency band.

[0122] In some embodiments, the non-legacy signal field 678 also includes one or more other sub-fields (not shown), which indicate one or more of the following: i) whether simultaneous transmissions occur in any other frequency band(s), ii) the number of other frequency bands in which simultaneous transmissions occur, iii) the corresponding total frequency bandwidth(s) of the other frequency band(s), and iv) the cumulative frequency bandwidth of all frequency bands in which simultaneous transmissions occur.

[0123] In some embodiments, the legacy preamble and the non-legacy preamble have, for example, the format discussed above with reference to Figures 6A to 6B and are used in conjunction with the transmissions discussed above with reference to Figures 2A to 2B and Figures 3A to 3B and.

[0124] Although certain orderings of fields and sub-fields are shown in Figures 6A to 6B in other embodiments, other suitable orderings of fields and sub-fields are used. In other embodiments, in addition to the fields and sub-fields shown in Figures 6A to 6B the PHY preamble further includes one or more other suitable fields / sub-fields. Similarly, in some embodiments, one or more of the fields / sub-fields shown in Figures 6A to 6B are omitted.

[0125] Example 1: A method for simultaneous transmission in multiple frequency bands, comprising: determining, at a communication device, whether simultaneous transmissions in a first frequency band and a second frequency band are to be synchronized in time; in response to the communication device determining that simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time, transmitting a first packet in the first frequency band starting from a first time, and transmitting a second packet in the second frequency band starting from the first time; and in response to the communication device determining that simultaneous transmissions in the first frequency band and the second frequency band are not to be synchronized in time, transmitting a third packet in the first frequency band starting from a second time, and transmitting a fourth packet in the second frequency band starting from a third time different from the second time.

[0126] Example 2. The method according to Example 1, wherein determining whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time comprises: determining whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time based on the frequency bandwidth of the frequency gap between the first frequency band and the second frequency band.

[0127] Example 3. The method according to Example 2, wherein determining whether the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time includes: comparing, at the communication device, the frequency bandwidth of the frequency gap with a threshold; in response to determining that the frequency bandwidth of the frequency gap is less than the threshold, determining that the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time; and in response to determining that the frequency bandwidth of the frequency gap is greater than the threshold, determining that the simultaneous transmissions in the first frequency band and the second frequency band are not to be synchronized in time.

[0128] Example 4. The method according to any one of Examples 1 or 2, wherein determining whether the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time includes: determining, based on the capabilities of one or more other communication devices to receive the simultaneous transmissions, whether the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time.

[0129] Example 5. The method according to Example 4, wherein determining whether the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time includes: determining whether any of the one or more other communication devices is capable of handling asynchronous transmissions in multiple frequency bands; in response to determining that at least one of the one or more other communication devices is not capable of handling asynchronous transmissions in multiple frequency bands, determining that the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time; and in response to determining that all of the one or more other communication devices are capable of handling asynchronous transmissions in multiple frequency bands, determining that the simultaneous transmissions in the first frequency band and the second frequency band are not to be synchronized in time.

[0130] Example 6. The method according to any one of Examples 1, 2, or 4, wherein determining whether the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized includes: determining whether the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized based on one or more of the following: i) the total frequency bandwidth of the first frequency band, ii) the total frequency bandwidth of the second frequency band, and iii) the cumulative frequency bandwidth of the total frequency bandwidth of the first frequency band and the total frequency bandwidth of the second frequency band.

[0131] Example 7. The method according to any one of Examples 1 to 6 further includes: generating the first packet having a first physical layer (PHY) preamble with a first duration; and generating the second packet having a second PHY preamble with a second duration different from the first duration.

[0132] Example 8. The method according to Example 7 further includes: generating the first PHY preamble to include information different from the second PHY preamble.

[0133] Example 9. The method according to any one of Examples 1 to 8, generating the second packet includes: generating the second packet to include a packet extension field such that the transmission of the second packet ends when the transmission of the first packet ends.

[0134] Example 10. The method according to any one of Examples 1 to 9, wherein: when the first packet and the second packet are transmitted: generating a first medium access control (MAC) layer data unit at the communication device, generating the first packet to include the first MAC layer data unit, generating a second MAC layer data unit at the communication device, generating the second packet to include the second MAC layer data unit; and when the third packet and the fourth packet are transmitted: generating a third MAC layer data unit at the communication device, generating the third packet to include the third MAC layer data unit, generating a fourth MAC layer data unit at the communication device, generating the second packet to include the fourth MAC layer data unit.

[0135] Example 11. The method according to any one of Examples 1 to 10, wherein: when the first packet and the second packet are transmitted: transmitting the first packet via a first number of spatial streams, and transmitting the second packet via a second number of spatial streams different from the first number of spatial streams; and when the third packet and the fourth packet are transmitted: transmitting the third packet via a third number of spatial streams, and transmitting the fourth packet via a fourth number of spatial streams different from the third number of spatial streams.

[0136] Example 12. A communication device includes: a wireless network interface device including: one or more integrated circuit (IC) devices, and a plurality of radio frequency (RF) radio devices including at least a first RF radio device and a second RF radio device, wherein the plurality of RF radio devices are at least partially implemented on the one or more IC devices; wherein the one or more IC devices are configured to implement the method according to any one of Examples 1 to 11.

[0137] Embodiment 13. A communication device includes: a wireless network interface device, including: one or more integrated circuit (IC) devices, and a plurality of radio frequency (RF) radio devices, at least including a first RF radio device and a second RF radio device, wherein at least part of the plurality of RF radio devices are implemented on the one or more IC devices. The one or more IC devices are configured to: determine whether simultaneous transmissions in a first frequency band and a second frequency band are to be synchronized, and in response to the communication device determining that simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized, control the first RF radio device to transmit a first packet in the first frequency band starting from a first time, and control the second RF radio device to transmit a second packet in the second frequency band starting from the first time. The one or more IC devices are further configured to: in response to the communication device determining that simultaneous transmissions in the first frequency band and the second frequency band are not to be synchronized, control the first RF radio device to transmit a third packet in the first frequency band starting from a second time, and control the second RF radio device to transmit a fourth packet in the second frequency band starting from a third time different from the second time.

[0138] Embodiment 14. The communication device according to Embodiment 13, wherein the one or more IC devices are further configured to: determine whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized based on the frequency bandwidth of the frequency gap between the first frequency band and the second frequency band.

[0139] Embodiment 15. The communication device according to Embodiment 14, wherein the one or more IC devices are further configured to: compare the frequency bandwidth of the frequency gap with a threshold; in response to determining that the frequency bandwidth of the frequency gap is less than the threshold, determine that simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized; and in response to determining that the frequency bandwidth of the frequency gap is greater than the threshold, determine that simultaneous transmissions in the first frequency band and the second frequency band are not to be synchronized.

[0140] Embodiment 16. The communication device according to any one of Embodiments 13 to 15, wherein the one or more IC devices are further configured to: determine whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized based on the capabilities of one or more other communication devices to receive the simultaneous transmissions.

[0141] Example 17. The communication device according to any one of Examples 13 to 16, wherein the one or more IC devices are further configured to determine whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized based on one or more of the following: i) the total frequency bandwidth of the first frequency band, ii) the total frequency bandwidth of the second frequency band, and iii) the cumulative frequency bandwidth of the total frequency bandwidth of the first frequency band and the total frequency bandwidth of the second frequency band.

[0142] Example 18. The communication device according to any one of Examples 13 to 17, wherein the one or more IC devices are further configured to generate the first packet having a first physical layer (PHY) preamble having a first duration; and generate the second packet having a second PHY preamble having a second duration different from the first duration.

[0143] Example 19. The communication device according to claim 18, wherein the one or more IC devices are further configured to generate the first PHY preamble to include information different from the second PHY preamble.

[0144] Example 20. The communication device according to any one of Examples 13 to 19, wherein the one or more IC devices are further configured to generate the second packet to include a packet extension field such that when the transmission of the first packet ends, the transmission of the second packet ends.

[0145] Example 21. The communication device according to any one of Examples 13 to 20, wherein the one or more IC devices are further configured to: when the first packet and the second packet are transmitted: generate a first media access control (MAC) layer data unit, generate the first packet to include the first MAC layer data unit, generate a second MAC layer data unit, and generate the second packet to include the second MAC layer data unit. The one or more IC devices are further configured to: when the third packet and the fourth packet are transmitted: generate a third MAC layer data unit, generate the third packet to include the third MAC layer data unit, generate a fourth MAC layer data unit, and generate the second packet to include the fourth MAC layer data unit.

[0146] Example 22. The communication device according to Example 21, wherein the wireless network interface device includes: a single media access control (MAC) layer processor implemented on the one or more IC devices; a baseband signal processor implemented on the one or more IC devices, wherein the baseband signal processor is coupled to the single MAC processor and the plurality of RF radio devices; and wherein when the first packet and the second packet are transmitted: the single MAC layer processor is configured to generate the first MAC layer data unit and the second MAC layer data unit, and the baseband processor is configured to generate the first packet and the second packet; wherein when the third packet and the fourth packet are transmitted: the single MAC layer processor is configured to generate the third MAC layer data unit and the fourth MAC layer data unit, and the baseband processor is configured to generate the third packet and the fourth packet.

[0147] Example 23. The communication device according to any one of Examples 13 to 122, wherein the one or more IC devices are further configured to: when the first packet and the second packet are transmitted: control the first RF radio device to transmit the first packet via a first number of spatial streams, and control the second RF radio device to transmit the second packet via a second number of spatial streams different from the first number of spatial streams; and when the third packet and the fourth packet are transmitted: control the first RF radio device to transmit the third packet via a third number of spatial streams, and control the second RF radio device to transmit the fourth packet via a fourth number of spatial streams different from the third number of spatial streams.

[0148] At least some of the various blocks, operations, and techniques described above can be implemented using hardware, a processor executing firmware instructions, a processor executing software instructions, or any combination thereof. When implemented using a processor executing software or firmware instructions, the software or firmware instructions can be stored in any computer-readable memory, such as on a magnetic disk, optical disk, or other storage medium, in RAM or ROM or flash memory, a processor, a hard disk drive, an optical disk drive, a tape drive, etc. The software or firmware instructions can include machine-readable instructions that, when executed by one or more processors, cause the one or more processors to perform various actions.

[0149] When implemented in hardware, the hardware can include one or more of discrete components, integrated circuits, application-specific integrated circuits (ASICs), programmable logic devices (PLDs), etc.

[0150] Although the present invention has been described with reference to specific examples, these examples are for illustrative purposes only and not intended to limit the present invention. However, changes, additions, and / or deletions may be made to the disclosed embodiments without departing from the scope of the present invention.

Claims

1. A method for simultaneous transmission in multiple frequency bands, comprising: Generating, at a communication device, a first packet for transmission in a first frequency band, including generating a first physical layer (PHY) preamble of the first packet, the first PHY preamble including a first field indicating a first total bandwidth spanned by the first packet; Generating, at the communication device, a second packet for transmission in a second frequency band, including generating a second PHY preamble of the second packet, the second PHY preamble including a second field indicating a second total bandwidth spanned by the second packet; Simultaneously transmitting, by the communication device, the first packet in the first frequency band and the second packet in the second frequency band, including: Starting to transmit the first packet in the first frequency band at a first time; Starting to transmit the second packet in the second frequency band at a second time different from the first time.

2. The method according to claim 1, wherein: Generating the first packet includes: generating the first PHY preamble of the first packet, the first PHY preamble further including a third field indicating the first frequency band for transmitting the first packet; Generating the second packet includes: generating the second PHY preamble of the second packet, the second PHY preamble further including a fourth field indicating the second frequency band for transmitting the second packet.

3. The method according to claim 1, further comprising: Generating the first PHY preamble having a first duration; Generating the second PHY preamble having a second duration different from the first duration.

4. The method according to claim 1, wherein: Generating the first packet includes: Generating the first packet having a first duration; Generating the first PHY preamble, the first PHY preamble including a first legacy signal field indicating the first duration; Generating the second packet includes: Generating the second packet having a second duration different from the first duration; Generating the second PHY preamble, the second PHY preamble including a second legacy signal field indicating the second duration.

5. The method according to claim 1, wherein simultaneously transmitting the first packet and the second packet in the first frequency band and the second frequency band includes: Transmitting the first packet via a first number of spatial streams; Transmitting the second packet via a second number of spatial streams different from the first number.

6. The method according to any one of claims 1 to 5, further comprising: At the communication device, determining whether simultaneous transmission in the first frequency band and the second frequency band is to be time-synchronized; In response to determining that simultaneous transmission in the first frequency band and the second frequency band is not to be time-synchronized, starting to transmit the first packet in the first frequency band at the first time and starting to transmit the second packet in the second frequency band at the second time.

7. The method according to claim 6, wherein determining whether simultaneous transmission in the first frequency band and the second frequency band is to be time-synchronized includes: Determine whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time based on the frequency bandwidth of the frequency gap between the first frequency band and the second frequency band.

8. The method according to claim 7, wherein determining whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time includes: Comparing the frequency bandwidth of the frequency gap with a threshold value at the communication device; In response to determining that the frequency bandwidth of the frequency gap is less than the threshold value, determining that simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time; In response to determining that the frequency bandwidth of the frequency gap is greater than the threshold value, determining that simultaneous transmissions in the first frequency band and the second frequency band are not to be synchronized in time.

9. The method according to claim 6, wherein determining whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time includes: Determining whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time based on the capabilities of one or more other communication devices that will receive the simultaneous transmissions.

10. The method according to claim 9, wherein determining whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time includes: Determining whether any of the one or more other communication devices is unable to handle asynchronous transmissions in multiple frequency bands; In response to determining that at least one of the one or more other communication devices is unable to handle asynchronous transmissions in multiple frequency bands, determining that simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time; In response to determining that all of the one or more other communication devices are able to handle asynchronous transmissions in multiple frequency bands, determining that simultaneous transmissions in the first frequency band and the second frequency band are not to be synchronized in time.

11. The method according to claim 6, wherein determining whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized includes: Determining whether simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized based on one or more of the following: i) the total frequency bandwidth of the first frequency band, ii) the total frequency bandwidth of the second frequency band, iii) the cumulative frequency bandwidth of the total frequency bandwidth of the first frequency band and the total frequency bandwidth of the second frequency band.

12. A wireless communication device, comprising: A wireless network interface device, comprising: One or more integrated circuit (IC) devices; A plurality of radio frequency (RF) radio devices, at least including a first RF radio device and a second RF radio device, the plurality of RF radio devices being at least partially implemented on the one or more IC devices; Wherein the one or more IC devices are configured to: Generate a first packet for transmission in a first frequency band, including generating a first PHY preamble of the first packet, the first PHY preamble including a first field indicating a first total bandwidth spanned by the first packet; Generate a second packet for transmission in a second frequency band, including generating a second PHY preamble for the second packet, the second PHY preamble including a second field indicating a second total bandwidth spanned by the second packet; Control the first RF radio device and the second RF radio device to simultaneously transmit the first packet in the first frequency band and the second packet in the second frequency band, including: Control the first RF radio device to start transmitting the first packet in the first frequency band at a first time; Control the second RF radio device to start transmitting the second packet in the second frequency band at a second time different from the first time.

13. The wireless communication device according to claim 12, wherein the one or more IC devices are configured to: Generate the first PHY preamble for the first packet, the first PHY preamble further including a third field indicating a first frequency band in which the first packet is transmitted; Generate the second PHY preamble for the second packet, the second PHY preamble further including a fourth field indicating a second frequency band in which the second packet is transmitted.

14. The wireless communication device according to claim 12, wherein the one or more IC devices are further configured to: Generate the first PHY preamble having a first duration; Generate the second PHY preamble having a second duration different from the first duration.

15. The wireless communication device according to claim 12, wherein the one or more IC devices are further configured to: Generate the first packet having a first duration; Generate the second packet having a second duration different from the first duration; Generate the first PHY preamble, the first PHY preamble including a first legacy signal field indicating the first duration; Generate the second PHY preamble, the second PHY preamble including a second legacy signal field indicating the second duration.

16. The wireless communication device according to claim 12, wherein the one or more IC devices are further configured to: Control the first RF radio device to transmit the first packet via a first number of spatial streams; Control the second RF radio device to transmit the second packet via a second number of spatial streams different from the first number.

17. The wireless communication device according to any one of claims 12 to 16, wherein the one or more IC devices are further configured to: Determine whether simultaneous transmissions in the first frequency band and the second frequency band are to be time synchronized; In response to determining that simultaneous transmissions in the first frequency band and the second frequency band are not to be time synchronized, start transmitting the first packet in the first frequency band at the first time and start transmitting the second packet in the second frequency band at the second time.

18. The wireless communication device according to claim 17, wherein the one or more IC devices are further configured to: Determine whether the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time based on the frequency bandwidth of the frequency gap between the first frequency band and the second frequency band.

19. The wireless communication device according to claim 18, wherein the one or more IC devices are further configured to: Compare the frequency bandwidth of the frequency gap with a threshold; In response to determining that the frequency bandwidth of the frequency gap is less than the threshold, determine that the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time; In response to determining that the frequency bandwidth of the frequency gap is greater than the threshold, determine that the simultaneous transmissions in the first frequency band and the second frequency band are to be not synchronized in time.

20. The wireless communication device according to claim 17, wherein the one or more IC devices are further configured to: Determine whether the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time based on the capabilities of one or more other communication devices that are to receive the simultaneous transmissions.

21. The wireless communication device according to claim 20, wherein the one or more IC devices are further configured to: Determine whether any of the one or more other communication devices are unable to handle asynchronous transmissions in multiple frequency bands; In response to determining that at least one of the one or more other communication devices is unable to handle asynchronous transmissions in multiple frequency bands, determine that the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized in time; In response to determining that all of the one or more other communication devices are able to handle asynchronous transmissions in multiple frequency bands, determine that the simultaneous transmissions in the first frequency band and the second frequency band are to be not synchronized in time.

22. The wireless communication device according to claim 17, wherein the one or more IC devices are further configured to: Determine whether the simultaneous transmissions in the first frequency band and the second frequency band are to be synchronized based on one or more of the following: i) the total frequency bandwidth of the first frequency band, ii) the total frequency bandwidth of the second frequency band, iii) the cumulative frequency bandwidth of the total frequency bandwidth of the first frequency band and the total frequency bandwidth of the second frequency band.

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