Patent Application
20200099503
The invention relates to wireless communications, and in particular relates to radio base stations and user equipment configured to communicate using dual frequency asymmetric time division duplexing.
Wireless communication networks are widely deployed to provide various communication services such as voice, video, messaging, packet data, unicast, multicast, broadcast, and the like. Currently, wireless networks are typically operated using one of two popular standards: a wide area network (WAN) standard referred to as The Fourth Generation Long Term Evolution (4G LTE) system; and a local area network (LAN) standard called Wi-Fi. Wi-Fi is generally used indoors as a short-range wireless extension of wired broadband systems, whereas the 4G LTE systems provide wide area long-range connectivity both outdoors and indoors using dedicated infrastructure such as cell towers and backhaul to connect to the Internet.
As more people connect to the Internet, increasingly chat with friends and family, watch and upload videos, listen to streamed music, and indulge in virtual or augmented reality, data traffic continues to grow exponentially. In order to address the continuously growing wireless capacity challenge, the next generation of LAN and WAN systems are relying on higher frequencies referred to as millimeter waves in addition to currently used frequency bands below 7 GHz. The next generation of wireless WAN standard referred to as 5G New Radio (NR) is under development in the Third Generation Partnership Project (3GPP). The 3GPP NR standard supports both sub-7 GHz frequencies as well as millimeter wave bands above 24 GHz. In 3GPP standard, frequency range 1 (FR1) covers frequencies in the 0.4 GHz-6 GHz range. Frequency range 2 (FR2) covers frequencies in the 24.25 GHz-52.6 GHz range. Table 1 provides examples of millimeter wave bands including FR2 bands that may be used for wireless high data-rate communications. Table 2 separately lists examples of FR2 bands in the 3GPP standard. In the millimeter wave bands above 24 GHz, a time division duplexing (TDD) scheme is generally preferred. However, regulations in most parts of the World allow using other duplexing schemes including frequency division duplexing (FDD).
Table 3 lists examples of FR1 bands in the 3GPP standard. We refer to the FR1 bands in the 3GPP standard, unlicensed 2.4 GHz and 5 GHz bands, 5.925-6.425 GHz and 6.425-7.125 GHz bands and any other spectrum band below 7 GHz as sub-7 GHz spectrum. The duplexing schemes used in the sub-7 GHz spectrum, among others, can be time division duplexing (TDD), frequency division duplexing (FDD), supplemental downlink (SDL) or supplemental uplink (SUL).
In addition to serving mobile devices, the next generation of wireless WAN systems using millimeter wave and sub-7 GHz spectrum are expected to provide high-speed (Gigabits per second) links to fixed wireless broadband routers installed in homes and commercial buildings.
The Fourth Generation Long Term Evolution (4G LTE) system and local area network (LAN) standard called Wi-Fi use orthogonal frequency-division multiplexing (OFDM) for encoding digital data on multiple carrier frequencies. A large number of closely spaced orthogonal sub-carriers are modulated with conventional modulation schemes such as BPSK, QPSK, 16-QAM, 64-QAM and 256-QAM. The next generation of wireless WAN standard referred to as 5G New Radio (NR) also uses orthogonal frequency-division multiplexing (OFDM).
Various aspects of the present disclosure are directed to radio base stations and user equipment (UE) configured to communicate using dual frequency asymmetric time division duplex (TDD). In one aspect, a transceiver configured to multiplex downlink and uplink signals on a first and a second frequency band using an asymmetric TDD includes a first antenna array configured to operate at a first frequency band and a second antenna array configured to operate at a second frequency band. The transceiver further includes a first radio frequency (RF) front-end transmit module and a first RF front-end receive module.
The transceiver also includes a first TDD switch operable to connect the first RF front-end transmit module to the first antenna array during a first TDD downlink time period when the transceiver is transmitting at the first frequency band and operable to connect the first RF front-end receive module to the first antenna array during a first TDD uplink time period when the transceiver is receiving at the first frequency band.
The transceiver also includes a second radio frequency (RF) front-end transmit module and a second RF front-end receive module. The transceiver also includes a second TDD switch operable to connect the second RF front-end transmit module to the second antenna array during a second TDD downlink time period when the transceiver is transmitting at the second frequency band and operable to connect the second RF front-end receive module to the second antenna array during a second TDD uplink time period when the transceiver is receiving at the second frequency band.
In an additional aspect of the disclosure, the transceiver includes a first digital to analog converter (DAC) coupled to the first RF front-end transmit module. The first DAC is configured to receive first digital transmit data when the transceiver is transmitting at the first frequency band and is operable to convert the first digital transmit data to first analog transmit signals. The transceiver also includes a first analog to digital converter (ADC) coupled to the first RF front-end receive module. The first ADC is configured to receive first analog receive signals when the wireless transceiver is receiving at the first frequency band and is operable to convert the first analog receive signals to first digital receive data.
In an additional aspect of the disclosure, the transceiver includes a second digital to analog converter (DAC) coupled to the second RF front-end transmit module. The second DAC is configured to receive second digital transmit data when the wireless transceiver is transmitting at the second frequency band and operable to convert the second digital transmit data to second analog transmit signals.
In an additional aspect of the disclosure, the transceiver includes a second analog to digital converter (ADC) coupled to the second RF front-end receive module. The second ADC is configured to receive second analog receive signals when the wireless transceiver is receiving at the second frequency band and operable to convert the second analog receive signals to second digital receive data. The first RF front-end transmit module is operable to convert the first analog transmit signals to first downlink signals. The first downlink signals are transmitted by the first antenna array on the first frequency band during the first TDD downlink time period. The first antenna array receives first uplink signals. The first RF front-end receive module is operable to convert the first uplink signals to the first analog signals during the first TDD uplink time period.
In an additional aspect of the disclosure, the second RF front-end transmit module is operable to convert the second analog transmit signals to second downlink signals. The second downlink signals are transmitted by the second antenna array on the second frequency band during the second TDD downlink time period.
In an additional aspect of the disclosure, the second antenna array receives second uplink signals. The second RF front-end receive module is operable to convert the second uplink signals to the second analog signals during the second TDD uplink time period.
In an additional aspect of the disclosure, the first TDD downlink time period is greater than the first TDD uplink time period, and in an additional aspect of the disclosure, the second TDD downlink time period is smaller than the second TDD uplink time period.
In an additional aspect of the disclosure, the first TDD downlink time period and the second TDD uplink time period are concurrent and have an equal length, and the first TDD uplink time period and the second TDD downlink time period are concurrent and have an equal length.
In an additional aspect of the disclosure the first TDD downlink time period and the second TDD uplink time period are non-concurrent and have an equal length, and the first TDD uplink time period and the second TDD downlink time period are non-concurrent and have an equal length.
In an additional aspect of the disclosure, a transceiver configured to multiplex downlink and uplink signals on a first and a second frequency band using an asymmetric time division duplex (TDD) includes a first antenna array configured to operate at the first frequency band and a second antenna array configured to operate at the second frequency band. The transceiver also includes a first radio frequency (RF) front-end transmit module and a first RF front-end receive module. The transceiver also includes a first TDD switch operable to connect the first RF front-end transmit module to the first antenna array during a first TDD downlink time period when the transceiver is transmitting at the first frequency band and operable to connect the first RF front-end receive module to the first antenna array during a first TDD uplink time period when the transceiver is receiving at the first frequency band. The transceiver also includes a second radio frequency (RF) front-end transmit module and a second RF front-end receive module. The transceiver also includes a second TDD switch operable to connect the second RF front-end transmit module to the second antenna array during a second TDD downlink time period when the transceiver is transmitting at the second frequency band and operable to connect the second RF front-end receive module to the second antenna array during a second TDD uplink time period when the transceiver is receiving at the second frequency band. The first TDD downlink time period and the second TDD uplink time period at least partially overlap in time, and the first TDD uplink time period and the second TDD downlink time period at least partially overlap in time. In an additional aspect of the disclosure, the first TDD downlink time period and the second TDD uplink time period are non-concurrent, and the first TDD uplink time period and the second TDD downlink time period are non-concurrent.
In an additional aspect of the disclosure, a user equipment (UE) configured to multiplex downlink and uplink signals on a first and a second frequency band using an asymmetric time division duplex (TDD) includes a first antenna array configured to operate at the first frequency band and a second antenna array configured to operate at the second frequency band. The UE further includes a first radio frequency (RF) front-end transmit module and a first RF front-end receive module. The UE also includes a first TDD switch operable to connect the first RF front-end transmit module to the first antenna array during a first TDD uplink time period when the UE is transmitting at the first frequency band and operable to connect the first RF front-end receive module to the first antenna array during a first TDD downlink time period when the UE is receiving at the first frequency band. The UE also includes a second radio frequency (RF) front-end transmit module and a second RF front-end receive module. The UE also includes a second TDD switch operable to connect the second RF front-end transmit module to the second antenna array during a second TDD uplink time period when the UE is transmitting at the second frequency band and operable to connect the second RF front-end receive module to the second antenna array during a second TDD downlink time period when the UE is receiving at the second frequency band.
In an additional aspect of the disclosure, the UE includes a first digital to analog converter (DAC) coupled to the first RF front-end transmit module. The first DAC is configured to receive first digital transmit data when the UE is transmitting at the first frequency band and operable to convert the first digital transmit data to first analog transmit signals. The UE also includes a first analog to digital converter (ADC) coupled to the first RF front-end receive module. The first ADC is configured to receive first analog receive signals when the UE is receiving at the first frequency band and operable to convert the first analog receive signals to first digital receive data.
In an additional aspect of the disclosure, the UE includes a second digital to analog converter (DAC) coupled to the second RF front-end transmit module. The second DAC is configured to receive second digital transmit data when the UE is transmitting at the second frequency band and operable to convert the second digital transmit data to second analog transmit signals. The UE also includes a second analog to digital converter (ADC) coupled to the second RF front-end receive module. The second ADC is configured to receive second analog receive signals when the UE is receiving at the second frequency band and operable to convert the second analog receive signals to second digital receive data. The first RF front-end transmit module is operable to convert the first analog transmit signals to first uplink signals, wherein the first uplink signals are transmitted by the first antenna array on the first frequency band during the first TDD uplink time period. The first antenna array receives first downlink signals, wherein the first RF front-end receive module is operable to convert the first downlink signals to the first analog signals during the first TDD downlink time period. The second RF front-end transmit module is operable to convert the second analog transmit signals to second uplink signals, wherein the second uplink signals are transmitted by the second antenna array on the second frequency band during the second TDD uplink time period. The second antenna array receives second downlink signals, wherein the second RF front-end receive module is operable to convert the second downlink signals to the second analog signals during the second TDD downlink time period. In an additional aspect, the first TDD downlink time period is greater than the first TDD uplink time period. The second TDD downlink time period is smaller than the second TDD uplink time period. In an additional aspect, the first TDD downlink time period and the second TDD uplink time period are concurrent and have an equal length, and the first TDD uplink time period and the second TDD downlink time period are concurrent and have an equal length. In an additional aspect, the first TDD downlink time period and the second TDD uplink time period are non-concurrent and have an equal length, and the first TDD uplink time period and the second TDD downlink time period are non-concurrent and have an equal length.
In an additional aspect of the disclosure, a user equipment (UE) configured to multiplex downlink and uplink signals on a first and a second frequency band using an asymmetric time division duplex (TDD) includes a first antenna array configured to operate at the first frequency band and a second antenna array configured to operate at the second frequency band. The UE further includes a first radio frequency (RF) front-end transmit module and a first RF front-end receive module. The UE also includes a first TDD switch operable to connect the first RF front-end transmit module to the first antenna array during a first TDD uplink time period when the UE is transmitting at the first frequency band and operable to connect the first RF front-end receive module to the first antenna array during a first TDD downlink time period when the UE is receiving at the first frequency band. The UE also includes a second radio frequency (RF) front-end transmit module and a second RF front-end receive module. The UE also includes a second TDD switch operable to connect the second RF front-end transmit module to the second antenna array during a second TDD uplink time period when the UE is transmitting at the second frequency band and operable to connect the second RF front-end receive module to the second antenna array during a second TDD downlink time period when the UE is receiving at the second frequency band. The first TDD downlink time period and the second TDD uplink time period at least partially overlap in time, and the first TDD uplink time period and the second TDD downlink time period at least partially overlap in time.
In an additional aspect of the present disclosure, a method for wireless communication between a radio base station and a user equipment (UE) by data multiplexing using dual frequency asymmetric time division duplex includes transmitting first downlink data by the radio base station during a first time division duplex (TDD) downlink time period on a first frequency band and receiving the first downlink data by the user equipment (UE) during the first TDD downlink time period on the first frequency band. The method further includes transmitting first uplink data by the UE during a first TDD uplink time period on the first frequency band and receiving the first uplink data by the radio base station during the first time division duplex (TDD) uplink time period on the first frequency band. The first downlink data and the first uplink data on the first frequency band are multiplexed using an asymmetric TDD, wherein the first TDD downlink time period is greater than the first TDD uplink time period. The method also includes transmitting second downlink data by the radio base station during a second TDD downlink time period on a second frequency band and receiving the second downlink data by the UE during the second TDD downlink time period on the second frequency band. The method also includes transmitting second uplink data by the UE during a second TDD uplink time period on the second frequency band and receiving the second uplink data by the radio base station during the second TDD uplink time period. The second downlink data and the second uplink data on the second frequency band are multiplexed using an asymmetric TDD, wherein the second TDD downlink time period is smaller than the second TDD uplink time period.
In accordance with the dual frequency asymmetric TDD, on frequency band f1 in the millimeter wave spectrum above 24 GHz or in the sub-7 GHz spectrum the wireless system 100 uses a downlink-heavy TDD configuration where downlink periods for communication from the base station to the devices are longer compared to the uplink periods for communication from the devices to the base station. On frequency band f2 in the millimeter wave spectrum above 24 GHz or in the sub-7 GHz spectrum the wireless system 100 uses an uplink-heavy TDD configuration where the uplink periods for communication from the devices to the base station are longer compared to the downlink periods for communication from the base station to the devices.
Referring to
Referring to
Using this arrangement, the gNodeBs 104, 108 and 112 and the communication devices 120, 124, 128, 132, 136 and 140 can continually transmit and receive signals without any disruption increasing system capacity and performance while making maximum use of both the transmit and receive hardware and software resources. For example, when sector B0 of base station gNodeB 104 is transmitting signals in the downlink on frequency band f1, it is also receiving signals from the communication device 124 in the uplink periods on frequency band f2. Similarly, when communication device 124 is receiving signals in the downlink on frequency band f1 from the sector B0 of base station gNodeB 104, it is also transmitting signals towards the sector B0 of base station gNodeB 104 in the uplink on frequency band f2. When sector B0 of base station gNodeB 104 is transmitting signals in the downlink on frequency band f2, it is also receiving signals from the communication device 124 in the uplink periods on frequency band f1. Similarly, when communication device 124 is receiving signals in the downlink on frequency band f2 from the sector B0 of base station gNodeB 104, it is also transmitting signals towards the sector B0 of base station gNodeB 104 in the uplink on frequency band f1.
In some embodiments, the frequency f1 is in the millimeter wave spectrum above 24 GHz and the frequency f2 in the sub-7 GHz spectrum. In other embodiments, the frequency f2 is in the millimeter wave spectrum above 24 GHz and the frequency f1 in the sub-7 GHz spectrum.
In yet other embodiments of the dual frequency asymmetric TDD, the downlink periods on the frequency band f1 and the uplink periods on the frequency band f2 are not synchronized and are not of the same length. Thus, the downlink periods on the frequency band f1 may be longer than the uplink periods on the frequency band f2, or the uplink periods on the frequency band f2 may be longer than the downlink periods on the frequency band f1. Likewise, the downlink periods on the frequency band f2 and the uplink periods on frequency band f1 are not synchronized and are not of the same length. Thus, the downlink periods on the frequency band f2 may be longer than the uplink periods on the frequency band f1, or the uplink periods on the frequency band f1 may be longer than the downlink periods on the frequency band f2.
Referring to
In the transmission time interval (TTI) numbered 9, the communication device 208 sends a data packet to the radio base station gNodeB 204 in the uplink on frequency f1. The radio base station gNodeB 204 sends an acknowledgment (ACK) in TTI numbered 11 at frequency f2 in the downlink for the data packet received from the communication device 208 in TTI numbered 9 on frequency f1.
Referring to
In the transmission time interval (TTI) numbered 9, the radio base station gNodeB 204 sends a data packet to the communication device 208 in the downlink on frequency f2. The communication device 208 sends an acknowledgment (ACK) in TTI numbered 11 at frequency f1 in the uplink for the data packet received from the radio base station gNodeB 204 in TTI numbered 9 on frequency f2.
The communication device 312 includes a transceiver 360 for transmitting and receiving signals at frequency f1 to and from the radio base station 304 and a transceiver 364 for transmitting and receiving signals at frequency f2 spectrum to and from the radio base station 304. The communication device 312 also includes an antenna array 368 for operation at frequency f1 for signal transmission and reception over the frequency f1 and an antenna array 372 for operation at frequency f2 for signal transmission and reception over the frequency f2. The communication device 308 further includes a baseband ASIC/modem, a digital signal processor (DSP), a communications protocol processor, a memory and networking components. The communication device 308 may also include additional functionalities such as various sensors, a display and a camera.
Referring to
The main services and functions of the RRC layer include broadcast of system information, paging, security functions including key management, QoS management functions, UE measurement reporting and control of the reporting, Detection of and recovery from radio link failure and NAS (Non-Access Stratum) message transfer to/from NAS from/to UE. RRC also controls the establishment, configuration, maintenance and release of Signaling Radio Bearers (SRBs) and Data Radio Bearers (DRBs); mobility functions including handover, context transfer, UE cell selection and reselection and control of cell selection and reselection.
The main services and functions of SDAP layer include mapping between a QoS flow and a data radio bearer and marking QoS flow ID (QFI) in both downlink and uplink packets. The main services and functions of the PDCP layer include: sequence numbering, header compression, header decompression, reordering, duplicate detection, retransmission of PDCP SDUs (Service Data Units), ciphering, deciphering, integrity protection, PDCP SDU discard, duplication of PDCP PDUs (Protocol Data Units), PDCP re-establishment and PDCP data recovery for RLC AM (Acknowledged Mode).
The RLC layer supports three transmission modes: Transparent Mode (TM), Unacknowledged Mode (UM) and Acknowledged Mode (AM). The main services and functions of the RLC layer depend on the transmission mode and include: transfer of upper layer PDUs, sequence numbering independent of the one in PDCP (UM and AM), error Correction through ARQ (AM only), segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs, reassembly of SDU (AM and UM), duplicate detection (AM only), RLC SDU discard (AM and UM), RLC re-establishment and protocol error detection (AM only).
The main services and functions of the MAC layer include: mapping between logical channels and transport channels, multiplexing/demultiplexing of MAC SDUs into/from transport blocks (TB) delivered to/from the physical layer, padding, scheduling information reporting, error correction through Hybrid ARQ, priority handling between UEs by means of dynamic scheduling and priority handling between logical channels.
Referring to
In the receive chain 404, the physical layer implements OFDM (Orthogonal Frequency Division Multiplexing) processing that includes FFT (Fast Fourier Transform) functions, removal of cyclic prefix (CP), port reduction, resource element de-mapping, channel estimation, MIMO detection, demodulation (QPSK, 16 QAM, 64 QAM and 256 QAM etc.), descrambling, physical-layer hybrid-ARQ processing, rate matching, bit-de-interleaving and channel decoding etc.
In some embodiments of the present disclosure, the physical layer functions are generally implemented in FPGAs (Field Programmable Gate Arrays), baseband ASIC, or digital signal processor (DSP). Consequently, the hardware resources are tied to either the transmit physical layer processing or the receive physical layer processing.
In existing conventional TDD systems, a radio base station gNodeB or a communication device is either in a transmit mode or in a receive mode. In a transmit mode, only transmit physical layer functions of existing conventional TDD systems are used, and when in a receive mode, only receive physical layer functions of existing conventional TDD systems are used, which results in inefficient utilization of FPGAs, baseband ASIC, or digital signal processor (DSP) resources.
The embodiments of the present disclosure provide an advantage over the existing conventional TDD systems by allowing more efficient utilization of FPGAs, baseband ASIC, or digital signal processor (DSP) resources. According to the dual frequency asymmetric TDD, both a radio base station gNodeB and communication devices can simultaneously operate in transmit and receive modes. For example, when the radio base station gNodeB is in a transmit mode on frequency band f1, it also is in a receive mode on frequency band f2. Similarly, when the communication devices are in a transmit mode on frequency band f2, they are also in a receive mode on frequency band f1. Thus, the embodiments of the present disclosure provide an efficient utilization of the FPGA, baseband ASIC, or digital signal processor (DSP) resources.
Referring to
The transmit chain 408 also includes RF front-ends 428 and 430 for frequency f1 and for frequency f2, respectively. The receive chain 404 includes RF front-end modules 432 and 434 for frequency f1 and for frequency f2, respectively. A transmit RF front-end module generally includes an analog up-conversion stage which can be implemented by using a frequency mixer driven by a Local Oscillator (LO), a filtering stage and one or more amplification stages using pre-power amplifiers (PPA) and power amplifiers (PA). A receive RF front-end module generally includes one or more amplification stages using low-noise-amplifiers (LNAs), a filtering stage and an analog down-conversion stage which can be implemented by using a frequency mixer driven by a Local Oscillator (LO). In some implementations, analog up-conversion stage analog down-conversion stage can be driven by the same Local Oscillator (LO).
The receive chain 404 also includes Analog Front End (AFE) modules 436 and 438 for frequency f1 and frequency f2, respectively. A receive Analog Front End (AFE) module generally includes an analog-to-digital conversion (ADC) stage and a digital down conversion (DCC) stage. The DDC converts the signal at the output of analog to digital convertor (ADC), centered at the intermediate frequency (IF), to complex baseband signal. In addition, DDC also decimates the baseband signal without affecting its spectral characteristics. In some implementations, the transmit Analog Front End (AFE) module and receive Analog Front End (AFE) module can be implemented in a single integrated circuit (IC).
Referring to
In operation, when the transceiver 400 transmits on frequency f1 and at the same time receives on frequency f2, the TDD switch 444 connects the transmit chain 408 to the antenna array 452 and disconnects the receive chain 404 from the antenna array 452, and the TDD switch 448 connects the receive chain 404 to the antenna array 454 and disconnects the transmit chain 408 from the antenna array 454. When the transceiver 400 receives on frequency f1 and at the same time transmits on frequency f2, the TDD switch 444 disconnects the transmit chain 408 from the antenna array 452 and connects the receive chain 404 to the antenna array 452, and the TDD switch 448 disconnects the receive chain 404 from the antenna array 454 and connects the transmit chain 408 to the antenna array 454.
In the embodiment of
In yet another embodiment of the present disclosure illustrated in
A downlink physical channel corresponds to a set of resource elements carrying information originating from higher layers. The downlink physical channels transmitted from the radio base station 508 and received by the communication device 504 include: Physical Downlink Shared Channel (PDSCH), Physical Broadcast Channel (PBCH) and Physical Downlink Control Channel (PDCCH). A downlink physical signal corresponds to a set of resource elements used by the physical layer but does not carry information originating from higher layers. The downlink physical signals transmitted from the radio base station 508 and received by the communication device 504 include: Demodulation reference signals (DM-RS), Phase-tracking reference signals (PT-RS) Channel-state information reference signal (CSI-RS) Primary synchronization signal (PSS) and Secondary synchronization signal (SSS). The TDD transmission interval for transmission of downlink physical channels and downlink physical signals by the radio base station on frequency f1 denoted as tDf1 is larger compared to TDD transmission interval for transmission of downlink physical channels and downlink physical signals by the radio base station on frequency f2 denoted as tDf2, that is, tUf1>tUf2.
In some disclosed embodiments, the TDD transmission interval for transmission of downlink physical channels and downlink physical signals by the radio base station on frequency f1 denoted as tDf1 is set equal to the TDD transmission interval for transmission of uplink physical channels and uplink physical signals by the communication device on frequency f2 denoted as tUf2, that is, tUf1=tUf2. In other words, the TDD reception interval for reception of downlink physical channels and downlink physical signals by the communication device on frequency f1 denoted as tDf1 is set equal to the TDD reception interval for reception of uplink physical channels and uplink physical signals by the by the radio base station on frequency f2 denoted as tUf2, that is, tUf1=tUf2. The TDD transmission interval for transmission of downlink physical channels and downlink physical signals by the radio base station on frequency f2 denoted as tDf2 is set equal to the TDD transmission interval for transmission of uplink physical channels and uplink physical signals by the communication device on frequency f1 denoted as tun, that is, tDf2=tUf1. In other words, the TDD reception interval for reception of downlink physical channels and downlink physical signals by the communication device on frequency f2 denoted as tDf2 is set equal to the TDD reception interval for reception of uplink physical channels and uplink physical signals by the by the radio base station on frequency f1 denoted as tun, that is, tDf2=tUf1.
By using this multiplexing approach in asymmetric TDD, the radio base station 508 and the communication device 504 more efficiently utilize hardware and software resources. When the radio base station 508 is transmitting downlink physical channels and downlink physical signals on frequency f1, it is also receiving uplink physical channels and uplink physical signals on frequency f2. For example, FPGA and ASIC resources implementing channel encoding, modulation, MIMO precoding, IFFT are used by the transmitter on frequency f1 while the FPGA and ASIC resources implementing channel decoding, demodulation, MIMO detection, FFT are used by the receiver on frequency f2 as illustrated in
When the radio base station 508 is transmitting downlink physical channels and downlink physical signals on frequency f2, it is also receiving uplink physical channels and uplink physical signals on frequency f1. For example, FPGA and ASIC resources implementing channel encoding, modulation, MIMO precoding, IFFT are used by the transmitter on frequency f2 while the FPGA and ASIC resources implementing channel decoding, demodulation, MIMO detection, FFT are used by the receiver on frequency f1. In other embodiments, when AFE/DAC (Analog Front End/Digital-to-Analog Converter) resources are used by the transmitter on frequency f2, AFE/ADC (Analog Front End/Analog-to-Digital Converter) resources are used by the receiver on frequency f1.
When the communication device 504 is transmitting uplink physical channels and uplink physical signals on frequency f1, it is also receiving downlink physical channels and downlink physical signals on frequency f2. For example, ASIC/modem resources implementing channel encoding, modulation, MIMO precoding, IFFT are used by the transmitter on frequency f1 while the ASIC/modem resources implementing channel decoding, demodulation, MIMO detection, FFT are used by the receiver on frequency f2. In other embodiments, when AFE/DAC (Analog Front End/Digital-to-Analog Converter) resources are used by the transmitter on frequency f1, AFE/ADC (Analog Front End/Analog-to-Digital Converter) resources are used by the receiver on frequency f2.
When the communication device 504 is transmitting uplink physical channels and uplink physical signals on frequency f2, it is also receiving downlink physical channels and downlink physical signals on frequency f1. For example, ASIC/modem resources implementing channel encoding, modulation, MIMO precoding, IFFT are used by the transmitter on frequency f2 while the ASIC/modem resources implementing channel decoding, demodulation, MIMO detection, FFT are used by the receiver on frequency f1. In other embodiments, when AFE/DAC (Analog Front End/Digital-to-Analog Converter) resources are used by the transmitter on frequency f2, AFE/ADC (Analog Front End/Analog-to-Digital Converter) resources are used by the receiver on frequency f1.
In some disclosed embodiments, baseband functions are implemented in an application-specific integrated circuit (ASIC) system-on-a-chip (SoC). In other embodiments, these functions can be implemented on general-purpose processors or in field-programmable gate array (FPGA) integrated circuits.
Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above in general terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system Those of skill may implement the described functionality in varying ways for each particular application, but such implementation decision should not be interpreted as causing a departure from the scope of the present disclosure.
The various illustrative logical blocks, modules and circuits described in connection with the disclosure herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, a controller, a microcontroller or a state machine.
The steps of a method or algorithm described in connection with the disclosure herein may be embodied in hardware, in a software module executed by a processor or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC, or the processor and the storage medium may reside in discrete components.
In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable medium includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one location to another. A non-transitory storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such non-transitory computer readable media can comprise RAM, ROM, EEPROM, CD-ROM, optical disk storage, magnetic disk storage, DVD, or any other medium that can be used to store program code means in the form of instructions or data structures and that can be accessed by a general purpose or special purpose processor. Any connection is termed a computer-readable medium. If the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk, as used herein, includes CD, laser disc, optical disc, DVD, floppy disk and other disks that reproduce data.
The previous description of disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and features disclosed herein.
