BR112017008756B1 - DYNAMIC BANDWIDTH SWITCHING FOR REDUCING POWER CONSUMPTION IN WIRELESS COMMUNICATION DEVICES - Google Patents

Abstract

CHANNEL ESTIMATION ENHANCEMENTS. Systems, methods, apparatus, and computer program products for performing dynamic bandwidth switching between control signals and data signals of different bandwidths are presented. Frame formats are presented in which control signals are transmitted in different bandwidths than data signals. Receiver architectures for receiving signaling formats are presented. A receiver can receive a relatively narrowband control signal while consuming relatively low power and then dynamically adjust characteristics of various components to receive a data signal at a higher bandwidth while consuming relatively higher power.

Description

[0001] The present application claims priority and benefit of United States Provisional Patent Application No. 62/073,603, filed October 31, 2014, which claims priority to the filing date of U.S. Patent Application No. 14/846,051 , filed September 4, 2015, both of which are incorporated herein by reference.

TECHNICAL FIELD

[0002] This application relates to wireless communications systems, and more particularly to signaling formats with variable signal bandwidth and associated adaptation of transceivers to conserve power consumption in mobile devices and base stations.

FUNDAMENTALS

[0003] The demand for wireless data services continues to increase exponentially. As data demand grows, techniques capable of delivering higher data rates to mobile devices continue to be of interest. One way to provide higher data rates is to increase the spectral bandwidth available for wireless communication systems.

[0004] Reflecting the trend of using increased bandwidth, current versions of the third generation Partnership Project (3GPP) Long Term Evolution (LTE) have up to 100 megahertz (MHz) available for communication. Additionally, it is possible that future networks, such as fifth generation (or 5G) networks, could utilize several hundred MHz or more in an attempt to meet future demand for data services.

[0005] As system bandwidth increases, data transmission can increase approximately proportionally without incurring a similar proportional increase in control overhead. Therefore, in future time division multiplexing (TDM) systems that multiplex data and control channels, there may be scenarios in which it would be inefficient for the control channels to occupy as much bandwidth as the data channels. There are inefficiencies both because spectral resources can be used unnecessarily that could be better used for other purposes and because mobile devices would be tuned to a higher bandwidth than necessary, thus wasting energy resources. Thus, there is a need to more efficiently control the multiplexing of data and control channels as available bandwidth increases in wireless communication systems.

SUMMARY

[0006] In one aspect of the disclosure, a wireless communication method includes transmitting a control signal to a mobile device using a first bandwidth and transmitting a data signal to the mobile device using a second bandwidth. bandwidth than the first bandwidth, the data signal is transmitted over a single carrier frequency.

[0007] In a further aspect of the disclosure, a method of wireless communication in a mobile device includes receiving a control signal having a first bandwidth and receiving a data signal having a second bandwidth wider than the first bandwidth, in which the control signal and data signal are received on a single carrier frequency.

[0008] In a further aspect of the disclosure, a computer program product for wireless communications includes a non-transitory, computer-readable medium having program code recorded, the program code including code for causing a transmitter transmits a control signal to a device using a first bandwidth. The program code further includes code for causing the transmitter to transmit a data signal to the device using a second bandwidth wider than the first bandwidth, wherein the control signal and the data signal are transmitted on a single carrier frequency.

[0009] In a further aspect of the disclosure, a computer program product for wireless communications includes a non-transitory, computer-readable medium, having program code recorded thereon, the program code including code for causing a receiver receives a control signal having a first bandwidth. The program code further includes code for causing the receiver to receive a data signal with a second bandwidth wider than the first bandwidth, wherein the control signal and the data signal are received in a single carrier frequency.

[0010] In a further aspect of the description, a mobile device includes an adjustable radio frequency (RF) front end configured to receive a control signal having a first bandwidth and receive a data signal having a second wider bandwidth. than the first bandwidth, where the control signal and the data signal are received on a single carrier frequency.

[0011] In a further aspect of the disclosure, a wireless communication apparatus includes an amplifier, an analog-to-digital converter (ADC), an analog filter connected between the amplifier and the ADC, and a control processor coupled to the amplifier, the ADC. , and the analog filter. The control processor is configured to, in response to receiving control information from a control signal with a first bandwidth, set the bandwidth of the amplifier and the ADC to a second bandwidth wider than that. the first bandwidth and set the ADC sampling rate according to the second bandwidth.

[0012] In a further aspect of the disclosure, a wireless communications apparatus includes a control processor configured to couple to an RF front end, adjust the RF front end to receive a control signal having a first bandwidth, and adjusting the RF front end to receive information having a second bandwidth wider than the first bandwidth, wherein the control signal and the data signal are received on a single carrier frequency.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 illustrates a wireless communications network in accordance with various aspects of the present disclosure.

[0014] FIG. 2 is a high-level block diagram of an adjustable receiver in accordance with various aspects of the present disclosure.

[0015] FIG. 3 illustrates a frame format and corresponding power consumption of an RF front end during, in accordance with, various aspects of the present disclosure.

[0016] FIG. 4 is a flowchart illustrating an exemplary method for receiving control signals and data in accordance with various aspects of the present disclosure.

[0017] FIG. 5 illustrates another frame format and the corresponding power consumption of an RF front end during reception of the illustrated frame format in accordance with various aspects of the present disclosure.

[0018] FIG. 6 is a flow chart illustrating another exemplary method for receiving control and data signals in accordance with various aspects of the present disclosure.

[0019] FIG. 7 illustrates an example frame and signal structure for a frequency division multiplexing (FDM) system in accordance with various aspects of the present disclosure.

[0020] FIG. 8 is a protocol diagram illustrating transmissions between a base station and a UE for an FDM system in accordance with various aspects of the present disclosure.

[0021] FIG. 9 is a protocol diagram illustrating signaling aspects between a UE and a base station to support dynamic bandwidth switching in accordance with various aspects of the present disclosure.

[0022] FIG. 10 is a block diagram of a transceiver in accordance with various aspects of the present disclosure.

[0023] Figs. 11 to 16 illustrate additional embodiments of a frame format in accordance with various aspects of the present disclosure.

DETAILED DESCRIPTION

[0024] The detailed description presented below, in connection with the attached drawings, is intended to be a description of various configurations and is not intended to represent the only configurations in which the concepts described herein can be practiced. The detailed description includes specific details for the purpose of providing a complete understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some cases, well-known structures and components are shown in block diagrams to avoid obscuring such concepts. The techniques described here can be used for various wireless communication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and others networks. The terms "network" and "system" are often used interchangeably. A CDMA network can implement a radio technology such as UTRA (Universal Terrestrial Radio Access), cdma2000, etc. UTRA includes WCDMA (Wideband CDMA) and other CDMA variants. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network can implement a radio technology such as GSM (Global System for Mobile Communications). An OFDMA network can implement radio technology such as E- UTRA (Evolved UTRA), '.'MB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash- OFDMA etc. UTRA and E-UTRA are part of UMTS (Universal Mobile Telecommunication System). 3GPP LTE (Long Term Evolution) and LTE-A (LTE-Advanced) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization called 3GPP ("3rd Generation Partnership Project"). CDMA2000 and UMB are described in documents from an organization called 3GPP2 ("3rd Generation Partnership Project 2"). The techniques described here can be used for the wireless networks and radio technologies mentioned above, as well as for other wireless networks and radio technologies, such as a new generation network (e.g., 5th Generation (5G)).

[0026] This disclosure recognizes that as available system bandwidth increases, the bandwidth used by data signals can be increased (and thus the data rate can be increased) without corresponding increases in signal channel signaling. control. Frame formats utilizing narrowband control signals and wideband data signals are disclosed. Frame formats provide adjustments to mobile device receivers to receive control signals with a wider bandwidth and data signals with a wider bandwidth. A receiver may use a low power mode to receive a control signal and then increase bandwidth and power consumption to receive a data signal. A transition interval or period can be inserted between a control signal and a data signal to allow the receiver timing to adjust to various signal bandwidths.

[0027] Power consumption in a wireless communications receiver scales with the bandwidth of the received signal. This disclosure generally relates to wireless communication networks that employ control signals and data signals of different bandwidths. Receivers in such networks are provided to take advantage of and adjust different bandwidths to reduce power consumption. For example, power consumption in wireless devices can be reduced because control signals can occupy a smaller bandwidth than in conventional systems.

[0028] FIG. 1 illustrates a wireless communications network 100, in accordance with various aspects of the disclosure. The wireless communications network 100 may be an LTE network or a next generation network (e.g., 5G). The wireless network 100 may include a number of base stations 110. A base station 110 may include an enhanced Node B in the LTE context. A base station may also be referred to as a base transceiver station or an access point.

[0029] Base stations 110 communicate with user equipment (UE) 120 as shown. A UE 120 can communicate with a base station 110 via an uplink and a downlink. The downlink (or forward link) refers to the communication link from a base station 110 to a UE 120. The uplink (or reverse link) refers to the communication link from a UE 120 to a base station 110.

[0030] The UEs 120 may be dispersed throughout the wireless network 100, and each UE 120 may be stationary or mobile. A UE may also be referred to as a terminal, a mobile station, a subscriber unit, etc. A UE 120 may be a cell phone, a smartphone, a personal digital assistant, a wireless modem, a laptop computer, a tablet computer, etc. Wireless communications network 100 is an example of a network to which several aspects of the disclosure apply. Other examples are WLANs.

[0031] FIG. 2 is a high-level block diagram of a tunable receiver 200. The tunable receiver 200 may be included in a UE 120. The tunable receiver 200 may include one or more antennas 210. If the tunable receiver 200 includes multiple antennas 210, it may any technique for multiple output and multiple input (MIMO) communication may be used. For convenience, the description will focus on an antenna 210a and its associated components with the understanding that the description applies to each antenna and its associated components.

[0032] In this example, the adjustable receiver 200 includes an RF front end 212a. In this example, the RF front end 212a includes an amplifier 215a, a mixer 220a, an analog filter 225a, and an analog-to-digital converter (ADC) 230a in communication with the antenna 210a as shown. Tunable receiver 200 employs a zero intermediate frequency (IF) architecture in which a signal received at antenna 210a is amplified by amplifier 215a and then downconverted directly to the baseband by mixer 220a in conjunction with local oscillator (LO) 240. A radio frequency (RF) amplifier, such as a low noise amplifier (LNA), is an example of amplifier 215a.

[0033] The analog filter 225a may be a low pass filter with an adjustable bandwidth. The received signal is typically a sum of a desired signal, interference, and data transport noise. In some scenarios, the bandwidth of the analog filter 225a is adjusted to prevent aliasing, allow the desired signal to pass with relatively little distortion to the ADC 230a, and attenuate interference and out-of-band noise.

[0034] The ADC 230a receives an analog signal at its input and samples it and digitizes the analog signal to produce a digital output. The sampling rate of the ADC 230a is sufficient to prevent or sufficiently limit aliasing of the signal and is generally at least twice the highest frequency component of the input signal. The sampling rate of the ADC 230a can be adjustable to satisfy the desired sampling rate according to signals with different input bandwidths.

[0035] The adjustable receiver 250 further includes a baseband processor 245. The baseband processor 245 receives signals from all receive chains and performs demodulation and decoding (if necessary) of the received signals.

[0036] The adjustable receiver further includes a control processor 255. The control processor 255 can direct the operation of the adjustable receiver 200. The control processor 255 generates one or more command signals (represented by dashed lines) intended for the amplifiers 215 , analog filters 225, ADC 230, and/or baseband processor 245. Command signals may also be referred to herein as internal control signals to distinguish the nomenclature of uplink and downlink control signals transmitted over wireless channels. wire.

[0037] The adjustable receiver 200 further includes a memory 250. The memory 250 can be any electronic component capable of storing information and/or instructions. For example, memory 250 may include random access memory (RAM), readout memory (ROM), RAM flash memory devices, optical storage media, erasable programmable readout memory (EPROM), registers, or combinations thereof. In one embodiment, memory 250 includes a non-transitory computer-readable medium.

[0038] Instructions or code may be stored in memory 250 that are executable by baseband processor 245 and/or control processor 255. The terms "instructions" and "code" should be interpreted broadly to include any type of computer readable statement. For example, the terms "instructions" and "code" may refer to one or more programs, routines, subroutines, functions, procedures, etc. "Instructions" and "code" may include a single computer-readable instruction or many computer-readable instructions.

[0039] The control processor 255 may be implemented using a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other device programmable logic, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The control processor 255 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other similar configuration. .

[0040] The amplifiers 215, analog filters 225 and/or ADCs 230 may be components with adjustable parameters such that the adjustable receiver 200 is capable of adapting to receive signals of different bandwidths such that power consumption varies according to bandwidth. Power consumption generally decreases as bandwidth decreases. For example, amplifiers 215 and analog filters 225 may have bandwidths that are adjustable, with the bandwidths adjusted in accordance with corresponding command signals. Additionally, the ADC 230 can have an adjustable sampling rate, with the sampling rates adjusted according to the corresponding command signal.

[0041] Consider an example scenario in which the adjustable receiver 200 expects a relatively narrowband signal followed by a relatively wideband signal. Before receiving the narrowband signal, the control processor 255 may adjust the bandwidths of the amplifiers 215 and analog filters 225 accordingly, and may adjust the sampling rate of the ADCs 230 accordingly. After receiving the narrowband signal but before receiving the wideband signal, the control processor 255 may increase the bandwidths of the amplifiers 215 and analog filters 225 to accommodate the wider bandwidth and may increase the signal rate. sampling of the ADCs to also accommodate the wider bandwidth. The greater the bandwidth of the signal to be received, the more power is required to process the signal.

[0042] It is understood that the zero IF architecture of FIG. 2 is one of many receiver architectures that are capable of tuning to receive signals of various bandwidths. Many different receiver architectures in accordance with the present disclosure can utilize amplifiers, filters and ADCs in various combinations whose parameters can be adjusted.

[0043] This disclosure is directed to any type of modulation scheme, but orthogonal frequency division multiplexing (OFDM) is used as a representative modulation. OFDM is a flexible modulation scheme that provides for adjusting the bandwidth of the transmitted signal in a direct manner.

[0044] OFDM modulation uses a number of subcarriers. The spacing between subcarriers can be fixed, and the total number of subcarriers used can be changed depending on the signal bandwidth. For example, the subcarrier spacing might be 4 kHz and the number of subcarriers might be 100, in which case the signal bandwidth is approximately 400 kHz (number of subcarriers times subcarrier spacing), not counting any guard bands . Thus, one way to scale bandwidth using OFDM is to scale the number of subcarriers. There are other well-known ways to scale the bandwidth of OFDM signals, such as scaling the frequency spacing between subcarriers. OFDM is demodulated using a fast Fourier transform (FFT), and the size of the FFT can be varied according to the number of subcarriers. Thus, baseband processor 245 may include at least one adjustable FFT per antenna to adapt demodulation to different signal bandwidths. The control processor 255 may control the baseband processor 245 to indicate the FFT size or other parameters to adapt the baseband processor 245 to OFDM signals with parameters that vary depending on the bandwidth. After an OFDM signal is formed, it can be transmitted using a separate high-frequency single carrier, sometimes referred to as an RF carrier. The available time-frequency resources can be partitioned into resource blocks. Each resource block can cover N subcarriers (e.g., 12 subcarriers) in one OFDM symbol duration.

[0045] The operation of the adjustable receiver 200 is further described with reference to Fig. 3. FIG. 3 illustrates a frame format 310 and the corresponding power consumption 360 of an example RF front end, such as RF front end 212a, during reception of the illustrated frame format. The 310 frame format is a TDM format in which time is divided into transmission time intervals (TTIs). Control and data signals are time division multiplexed within a TTI. FIG. 3 illustrates an example sequence of signals transmitted within this frame format 310.

[0046] A TTI may refer to the duration of a transmission on the radio link. A TTI can be related to the size of data blocks passed from the higher network layers to the radio link layer. In some embodiments, the duration of data symbols, such as OFDM symbols, is fixed, and there are a predetermined number of data symbol periods during each TTI. For example, each TTI can be any number of symbol periods, such as 8, 10, or 12 symbol periods, as examples.

[0047] In wireless communications systems, a downlink control signal may include information for a UE relating to the establishment, maintenance or termination of a data session. For example, a downlink control signal in a TTI may provide information to a UE about whether a downlink data signal follows in the TTI and, if so, the control signal may indicate a bandwidth of the downlink data signal in the TTI. data.

[0048] The 310 frame format is designed with the aim of reducing power consumption in UE receivers. A control signal 315 is transmitted at the beginning of each TTI. The control signal uses a relatively narrow bandwidth compared to data signals. The bandwidth of the control signals is sufficient to transmit control information to the intended UE(s), and it is not necessary to use the larger bandwidths used for data signals for the relatively small amount of control information. In a TTI, the control signal indicates whether there is a data signal that follows the control signal. In some embodiments, the bandwidth used for data signals is variable, in which case the control signal also indicates the bandwidth used for the data signal that follows. Alternatively, in some embodiments, the data signals always occupy a certain bandwidth (such as the entire bandwidth), in which case the bandwidth of the data signal is understood or implied and there is no need for the control signal transmit bandwidth information.

[0049] Each of the transmitted signals is transmitted using a single carrier frequency fc. Using a single carrier simplifies receivers compared to systems using carrier aggregation. Carrier aggregation typically requires the use of multiple LOs, whereas the signaling schemes described here can utilize only one LO. However, the approaches described in the present disclosure can also be applied to multiple carrier frequencies.

[0050] The frame formats disclosed herein, such as frame format 310, can apply regardless of the number of antennas used in the transmitting entity or the receiving entity. For example, in a SISO system, the signal is transmitted from the transmitting antenna and received at the receiving antenna. As another example, in a MIMO system, the illustrated frame formats are transmitted from at least one antenna. Each antenna among a plurality of antennas may transmit the same or a different pilot structure. In one embodiment, the illustrated frame format 310 will be received by a receiving antenna and may be part of a composite signal that is a sum of signals from a plurality of antennas.

[0051] In this example, at the nth TTI (TTIn), control signal 315 indicates to the designated UE that no data follows in the TTI. The tunable receiver 200 may be used to receive the control signal 315. After the tunable receiver 200 receives the control signal 315 in TTIn, the RF front end components 215, 225, and 230 may be temporarily turned off or turned off by the processor. control module 255, placing the adjustable receiver 200 into a "micro-sleep" state. For example, a switch may be placed between a component, such as an amplifier 215, an analog filter 225, and/or an ADC 230, and its power supply, with the switch being opened for a period of time to turn off the power. for the component. Another example of "micro-sleep" is placing a component in an inactive state in which it receives a reduced amount of power to operate at a reduced capacity.

[0052] The RF power consumption 360 of an RF front end, such as the RF front end 212a in the adjustable receiver 200, is illustrated in Fig. 3 during reception of various signals. For example, during reception of control signal 315 in TTIn, the power consumption is represented by 365. After determining that there is no data, the adjustable receiver 200 transitions to a micro-sleep state, and the power consumption during this transition is represented by 370. The decrease in energy consumption is represented as a linear decrease over time, but the actual decrease in energy consumption may be non-linear but decreasing over time nonetheless. During the TTI interval after being placed in microsleep, RF power consumption is much lower than when a signal is being received because amplifiers 215, analog filters 225, and ADC 230 have been turned off.

[0053] Shortly before TTIn+1, control processor 255 informs amplifiers 215, analog filters 225, and ADC 230 to turn on before receiving control signal 315 during TTIn+1. The power consumption during this transition is represented by 375, and the power consumption during reception of the control signal 315 at TTIn+1 is represented by 380. Components in the receiver 200 that have been turned off require a period of time to turn on enough to receive a signal.

[0054] In this example, control signal 315 is followed by data signal 325 at TTIn+1. The baseband processor 245 demodulates the control signal 315 and provides control signal information to the control processor 255. The information in the control signal 315 indicates to the control processor 255 that a data signal will follow. In some scenarios, the data signal 325 is a wider bandwidth than the control signal 315. In response, the control processor 255 tells the amplifiers 215, analog filters 225, and ADC 230 to adjust accordingly to the bandwidth. wider band. That is, the bandwidths of the amplifiers 215 and analog filters 225 are increased, and the sampling rate of the ADCs 230 is also increased. In some embodiments, the control processor 255 also tells the baseband processor 245 to adapt according to the increased bandwidth. For example, for demodulation of OFDM signals, the control processor 255 informs the baseband processor 245 to adjust the FFT size or other parameters appropriately to demodulate the input data signal.

[0055] Frame format 310 can further provide frequency division multiplexing (FDM) between users. For example, bandwidth B data signal 325 may be partitioned in the frequency domain with different portions of bandwidth B assigned to different users. The RF front end 212 for a user may further be suitably adjusted to bandwidth B with the extraction and demodulation of the desired portion being performed digitally in the frequency domain using OFDM techniques.

[0056] In one embodiment, the control signal 315 indicates not only which data will follow but also indicates the bandwidth of the data signal 325. In this case, the control processor 255 determines the bandwidth. In other embodiments, the data signal 325 always occupies the same bandwidth, such as all available bandwidth, in which case the bandwidth of the data signal may be understood to be a certain value and there may be no need to include an indication in the control signal. If the bandwidth of the data signals is allowed to vary, adjustable receiver components 200 are adjusted from the data signal to the data signal to receive using just enough bandwidth, sufficient to cover the bandwidth of the data signal to receive. interest, rather than always tuning to receive using all of the system's available bandwidth.

[0057] There is a transition period 320 between the control channel 315 and the data signal 325 to allow the adjustable receiver 200 to adjust to the different bandwidth. The transition period 320 may be referred to as a switching interval because the receiver 200 is switching from one bandwidth to another. The switching interval can be quantized to an integer number of symbol periods, such as OFDM symbol periods. The power consumption during this transition period 320 is represented by 385, and the power consumption during reception of the data signal 325 is represented by 390.

[0058] There is a transition period 330 between the data signal 325 and the next control signal 315 at TTIn+2. The transition period 330 allows the adjustable receiver time 200 to move to a lower bandwidth for the control signal 315. The power consumed during the transition period 330 is represented by 395.

[0059] Some conventional TDM systems typically do not include transition periods 320 and 330 to allow a receiver to adjust. One reason is that in some conventional TDM systems the control signal is transmitted using the same bandwidth as the data signal so that receivers do not need to transition between different bandwidths. Thus, the power consumed during transition periods 320 and 330 represents a power penalty for the signaling scheme in Fig. 3 compared to some conventional systems. However, there is substantial power savings during reception of the control signal 315 in the frame format illustrated in Fig. 3. The power savings include the power difference between the RF power consumed during reception of the data signal and the RF power consumed during reception of the control signal. The corresponding energy savings are calculated as an area under the power curves. Under certain conditions, the total power savings exceed the power penalty, in which case the frame format and corresponding adjustable receiver 200 extend battery life compared to conventional TDM systems.

[0060] FIG. 4 is a flow chart illustrating an exemplary method 400 for receiving control and data signals. Method 400 may be implemented in tunable receiver 200, and method 400 is described with reference to tunable receiver 200. Signals that are received in method 400 are transmitted by a base station 110 or other type of access point. Instructions or code may be stored in memory 250 that are executable by control processor 255 in adjustable receiver 200 of Fig. 2 to implement method 400.

[0061] Method 400 begins at block 410. At block 410 a narrowband control signal is received and processed by adjustable receiver 200. The control signal is referred to as a narrowband control signal because its bandwidth is typically lower than data signals, as illustrated in the signaling schematic in Fig. 3. In block 415, a decision is made whether a data signal follows the control signal in the current TTI. The control signal will contain this information and the control signal will be demodulated to extract this information.

[0062] If it is determined that no data signal follows the control signal in the current TTI, the method proceeds to block 440, in which power is supplied to certain RF front end components, such as amplifiers 215, analog filters 225 and/or ADCs 230, is reduced to place the components into a microsleep state. Control processor 255 may send signals to components in receiver 200 to control their state as previously described. After a period of time, at block 445 the components are directed to turn on or "wake up" to prepare to receive another control signal at block 410. Receiver 200 may wait until just before the start of the next TTI to request that the control components RF front end to wake up.

[0063] If it is determined in block 415 that a data signal follows the control signal, the method proceeds to block 420. In block 420, an RF front end 212a of the receiver 200 is adjusted to receive the data signal. As described previously, the control signal may contain information about the expected bandwidth of the data signal. Alternatively, the bandwidth of the data signal can be understood as being a certain value. In both cases, the RF front end is adjusted. Control processor 255 controls the adjustment. The baseband processor 245 may also be tuned.

[0064] Then in block 425 the data signal is received and processed. After the data signal is received at block 425, the RF front end is adjusted to receive a control signal at block 430 and the method returns to block 410 to begin again. Method 400 continues for the desired time for a communication session. In some embodiments, a control signal is transmitted at the beginning of each TTI and no further control signals are transmitted within each TTI. In other embodiments, at least one additional control signal is transmitted in each TTI. For example, there may be a control signal at the beginning of a TTI and another control signal in the middle of the TTI.

[0065] FIG. 5 illustrates another frame format 510 and the power consumption of an RF front end 560 during reception of the illustrated frame format. The 510 frame format is a TDM format in which time is divided into transmission time intervals (TTIs) and control signals and data signals are time division multiplexed. Figure 5 illustrates a signal sequence transmitted within this 510 frame format.

[0066] The signal sequence transmitted in frame format 510 is different from frame format 310 in that if a data signal is transmitted, the next control signal is transmitted using the bandwidth as the mode data signal. that there is no switching time or switching interval to adjust an RF front end. Since there is no need to adjust the RF front end, a data signal can be transmitted up to the TTI limit. The signaling format trades the potential for power savings with a narrower band control signal against the benefit of being able to eliminate dead time for signaling due to switching. Thus, the signaling scheme uses either narrowband or wideband control signals, depending on whether the control signal follows a data signal.

[0067] The similarities and differences between the signaling scheme illustrated in Fig. 5 and the signaling scheme in Fig. 3 can be understood with reference to Fig. 6. FIG. 6 is a flow chart illustrating an exemplary method 600 for receiving control and data signals. In Fig. 6, blocks 410-425, 440 and 445 are the same as the corresponding blocks in Fig. 4.

[0068] After a data signal is received in block 425, method 600 proceeds to block 610 in which a wideband control signal is received. The control signal can be referred to as a wideband control signal because the bandwidth is the same as the previously received data signal and the data signal bandwidth is typically greater than the signal bandwidth narrowband control. The control signal 515 in frame format 510 in Fig. 5 is an example of a narrowband control signal, and the control signal 530 is an example of a wideband control signal. The narrowband control signal 515 is followed by a transition period 520 to allow an RF front end to adjust to receive the data signal 525. There is no transition period required between the data signal 525 and the signal control 530 because the bandwidths are equal.

[0069] As previously discussed in relation to Fig. 3, frame format 510 can further provide FDM between users. For example, bandwidth B data signal 525 may be partitioned in the frequency domain with different portions of bandwidth B assigned to different users. Likewise, the control signal 530 can be divided in a similar way. The RF front end 212 for a user may further be suitably adjusted to bandwidth B with the extraction and demodulation of the desired portion being performed digitally in the frequency domain using OFDM techniques.

[0070] Next in decision block 615, a determination is made whether a data signal follows the wideband control signal in the TTI. If the data follows the wideband control signal, in one embodiment then the data is transmitted in the same bandwidth as the control signal, so there is no need to adjust the RF front end and the data signal is received in block 620. In another embodiment, the data is transmitted generally at a bandwidth B that may be greater or less than the bandwidth of the control signal, whereby there may be a transition period during which the RF front end is adjusted to receive the data signal.

[0071] On the other hand, if there is no data signal following the wideband control signal, then method 600 proceeds to block 440. In block 440, power supplied to certain RF front end components, such as such as amplifiers 215 , analog filters 225 , and/or ADCs 230 , is reduced to place the components into a microsleep state. After a period of time, at block 445 the components are directed to turn on or "wake up" to prepare to receive another control signal at block 410. Receiver 200 may wait until just before the start of the next TTI to request that the control components RF front end to wake up. As part of the wake-up process, the bandwidth and sampling rate(s) of the RF front end are set to receive a narrowband control signal. Instructions or code may be stored in memory 250 of adjustable receiver 200 that are executable by control processor 255 to implement method 600.

[0072] FIG. 7 illustrates an example frame and signal structure for an FDM system. The carrier frequency for data assigned to a given UE is not fixed and may vary. In the FDM scheme, the total bandwidth of the system can be divided into a plurality of frequency bands so that data signals for different UEs can be transmitted simultaneously in different frequency bands. For example, the data signal for UE1 710 and the data signal for UE2 720 overlap in time during TTI1 but do not overlap in frequency. A carrier signal at the center frequency of each of the data signals illustrated in Fig. 7 is used to transmit the various data signals.

[0073] The bandwidth allocated to data signals for a given UE may vary over time, as illustrated by comparing data signals 710 and 730 addressed to UE1, for example. A base station may decide to vary the bandwidth for a particular UE due to variations in the amount of data available for transmission as a function of time, for example.

[0074] Some conventional FDM schemes transmit OFDM signals using the full available bandwidth for downlink transmissions, with different groups of subcarriers within the complete signal allocated to different UEs. As a consequence, each UE typically processes all bandwidth to extract the subcarrier group(s) allocated to the UE. In comparison, when the RF carrier frequency is allowed to vary from transmission to transmission, each UE is notified of which RF carrier is being used for its signals. However, the benefit of the multi-RF carrier approach is that bandwidth can be used more efficiently if data signals are allowed to use different RF carriers so that each UE does not have to process the entire bandwidth. and can use the RF carrier dedicated to it.

[0075] FIG. 8 is a protocol diagram illustrating signaling aspects between a UE 120 and a base station 110 for supporting FDM with variable bandwidths. In this example, control signals are transmitted over a different channel than data signals. The control channel may be in a different frequency band or a different time slot, for example. A control signal indicates the center frequency (whether the center frequency is dynamic) and the bandwidth of an associated data signal. The data signal is then sent using the designated bandwidth and center frequency. In a time interval between the control signal and the data signal, the receiver of the UE 120 is tuned to the bandwidth of the data signal. This process is repeated as long as there is data to transport between the base station 110 and the UE 120.

[0076] The base station 110 can coordinate this process across different UEs 120 to efficiently utilize the available spectral bandwidth. An example of this coordinated process has been described with respect to Fig. 7.

[0077] FIG. 9 is a protocol diagram illustrating signaling aspects between a UE 120 and a base station 110 to support variable bandwidth signaling. First, the UE 120 transmits a capability message to the base station 110. The capability message may provide one or more indications corresponding to a number of parameters and capabilities of the UE 110. The capability message may include an indication whether the UE 110 is capable of dynamically switching between signals of various bandwidths. The capability message may further include an indication of switching latency for the UE 120, so that the base station 110 may respond by inserting or reserving a time interval between control and data signals to allow the UE 120 to adjust its RF front end. The time slot accommodates the switching latency indicated by a UE.

[0078] The base station 110 then transmits a reply message in response to the capability message. The response message may provide one or more indications corresponding to a number of parameters and capabilities. For example, the response message may indicate that dynamic bandwidth switching is enabled. Dynamic bandwidth switching can be enabled or disabled as often as desired during a connection. Thus, messages indicating that dynamic bandwidth switching is enabled or disabled can be transmitted by the base station 110 with the desired frequency.

[0079] The response message may also indicate the time offset between a control signal and the corresponding data signal in a TTL. The time offset may be based on the switching latency indicated in the capacity message. The time shift would accommodate the latency required to decode the control signal and allow the RF front end to switch bandwidths. The response message may also indicate whether the bandwidth is maintained at a wide bandwidth from the data signal to the next control signal, as illustrated in Fig. 5, or returns to a narrow bandwidth, as illustrated in Fig. 3. Alternatively, a preceding control signal may also indicate whether the bandwidth is maintained at a wide bandwidth from the data signal to a following control signal, as illustrated in Fig. 5, or returns to a bandwidth narrowband, as illustrated in Fig. 3.

[0080] Alternatively, base station 110 may decide not to enable dynamic bandwidth switching. If dynamic bandwidth switching is not enabled, control signals occupy the same bandwidth as data signals and there is no time offset between control signals and data signals.

[0081] After the capability message and response message have been exchanged, transmission of control information and data may proceed as needed. In the example illustrated in Fig. 9, a control signal is transmitted by the base station 120 and received by the UE 110. Next, the UE 110 adjusts its RF front end, and then a data signal is transmitted by the station base 120 and received by the UE 110.

[0082] FIG. 10 is a block diagram of a transceiver 900 that implements aspects of this disclosure. Transceiver 900 comprises antennas 210, baseband processor 245, memory 250, and controller/processor 255 as previously described. The transceiver further includes RF receive (Rx) front ends 910. Each Rx RF front end 910 may include an amplifier, an analog filter, and an ADC as described with respect to Fig. 2. Other Rx RF front end architectures are compatible with this disclosure. For example, some Rx RF front-end architectures perform most of the processing in the analog domain and some Rx RF front-end architectures perform most of the processing in the digital domain. Additionally, some Rx RF front-end architectures perform most processing at an intermediate frequency (IF) rather than baseband. These Rx RF front ends can be adjusted to accommodate differences in control signal and data signal bandwidth.

[0083] The transceiver further includes transmit (Tx) RF front ends 920. Each Tx RF front end 920 accepts a stream of digital data symbols from the baseband processor and converts the digital data symbols into an analog signal for transmission through the corresponding antenna 210.

[0084] The transceiver 900 is suitable for a base station 110 or for a UE 120. When the transceiver 900 is in a transmit mode, the Tx RF front ends 920 are engaged and the controller/processor 255 controls the Tx RF front ends 920 Tx RF 920 as well as baseband processor 245 to generate signals of various bandwidths. The combination of the Tx RF front end 920 and the baseband processor 245 is an example of a transmitter. The combination of Rx RF front end 910 and baseband processor 245 is an example of a receiver. An Rx RF front end 910 may comprise the RF front end 212 described above.

[0085] In addition to the previously described capabilities for demodulating OFDM symbols, baseband process 245 may additionally be configured to modulate OFDM symbols. OFDM symbol modulation is well known in the art and in some embodiments an inverse FFT (IFFT) is performed to convert frequency domain data to the time domain. As described previously, there are several techniques for changing the bandwidth of OFDM signals. One technique involves varying the number of subcarriers used to generate OFDM signals.

[0086] Information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles or any Your combination.

[0087] FIG. 11 illustrates another frame format 1110. The frame format is a TDM format in which time is divided into TTTs and control signals and data signals are time multiplexed. FIG. 11 illustrates a sequence of signals transmitted within this 1110 frame format.

[0088] Control signals 1115 are narrowband control signals. In one embodiment, a base station allows a full TTI duration for bandwidth switching delay of a receiver. There are at least two options for signaling using control signals 1115. In a first option, the control signal 1115 in TTIn has a bandwidth switching indicator to activate widening of the forward RF bandwidth to receive bandwidth data. wider bandwidth at TTIn+1. In this option, control signal 1115 at TTIn+1 indicates which frequency range is assigned to data at TTIn+1. In a second option, the assignment of data radio blocks 1125 in TTTn+1 is allocated or pre-programmed using control signal 1115 in TTIn. Once a wide radio forward bandwidth is configured for TTIn+1, programming can return to normal (i.e., without preprogramming) for subsequent TTIs. For example, control signal 1115 in TTIn+2 indicates the use of data resources 1135 and 1145 in TTIn+2.

[0089] An advantage of the first option is that the scheduler at a base station only needs to know that the UE will be scheduled at the next TTI to set the indicator. The base station scheduler does not need to pre-program and avoids a corresponding increase in complexity. An advantage of the second option is that there is a saving of control channel resource in that there is no switching bandwidth indicator.

[0090] The receiver bandwidth envelope is shown in Fig. 11. The receiver bandwidth envelope represents the frequency range as a function of time used by a receiver, such as the adjustable receiver 200, in the format of frame of interest. During the transition period 1120, the receiver bandwidth may transition from a relatively narrow bandwidth for receiving the control signal 1115 to a relatively wide bandwidth (in this embodiment, the total bandwidth of the system or total available data bandwidth) for receiving data. Likewise, during the transition period 1130, the receiver bandwidth may transition from a relatively wide bandwidth to a relatively narrow bandwidth, as shown.

[0091] FIG. 12 illustrates another frame format 1210. In this frame format a data signal can be allocated only to a last fraction or portion of a TTI, so that there is sufficient time for the receiver bandwidth to pass a bandwidth narrow bandwidth for receiving a control signal to a wider bandwidth for receiving a given signal. For example, in TTIn the control signal 1215 may indicate that there will be a data signal 1225 later in the TTI. Thus, a shorter duration of a TTI than the example in Fig. 11 may be available for receiver bandwidth switching. During the transition period 1220 the receiver bandwidth is increased. One such example of receiver boost is illustrated by the receiver bandwidth envelope in Fig. 12.

[0092] Once the receiver is moved to a wider bandwidth in TTIn, the data allocation can span the entire TTI, including the option to multiplex with the frequency control channel. For example, control signal 1215 in TTIn+1 may indicate the bandwidths of data signals 1235 and 1245. Control signals that are transmitted after the receiver has transmitted to a higher bandwidth may be referred to as wideband control signals, and in some embodiments, a wideband control signal refers to a control signal and one or more data signals that are transmitted simultaneously in different frequency bands (i.e., division multiplexing frequency). An example of a wideband control signal is the control signal 1215 at TTIn+1 in Fig. 12, and this control signal is frequency division multiplexed with data signals 1235 and 1245. In some embodiments, during a time interval in which a wideband control signal is transmitted, the transmitted signal includes a control signal portion and a data signal portion.

[0093] FIG. 12 also illustrates a countdown mechanism for returning a receiver to a narrow band for receiving control signals. At TTIn+2, control signal 1215 indicates that there is no data within TTIn+2. Thus, TTTn+2 is a candidate for returning the receiver bandwidth to a narrow bandwidth using previously described mechanisms - for example, in relation to Fig. 2. However, rather than having a receiver transition frequently between bandwidth, a countdown mechanism is used. In the first TTI in which there is no data to transmit, a counter is set to a maximum value, such as four, three, two, one, or any integer value. In the embodiment of Fig. 12, the maximum value is one. The counter is decremented with each successive consecutive TTI that contains no data. If a TTI contains data, the counter is reset to the maximum value. In the example in Fig. 12, at TTIn+3, if there is no data to transmit, the counter is decremented to zero. A counter value of zero indicates that the receiver must then reduce its bandwidth. For example, at TTIn+3, the receiver reduces its bandwidth as shown (the receiver envelope transitions from a wide bandwidth to a narrow bandwidth during the transition period 1230). An alternative to the countdown timer is that the receiver bandwidth is reduced to a narrow bandwidth on the first TTI that contains no data.

[0094] FIG. 13 illustrates another frame format 1310. The frame format 1310 is similar to the frame format 1110, except that for the frame format 1310, an embodiment of a receiver is enhanced with bandwidth adaptation according to the data allocation. . For example, in Fig. 11 during TTIn+i the receiver bandwidth is set to the system bandwidth or the maximum supported data bandwidth, while in Fig. 13 the receiver bandwidth during TTIn+ i is set just large enough to receive the data signal 1325 while remaining symmetric about the center frequency.

[0095] Furthermore, as in Fig. 11 there are at least two options for signaling using control signals 1115. In a first option, the control signal 11-15 in TTIn has a bandwidth switch indicator plus bandwidth information. bandwidth to trigger widening of the RF forward bandwidth to be just wide enough to receive wider bandwidth data at TTIn+1. In a second option, the assignment of data radio blocks 1125 in TTIn+1 is allocated or pre-programmed using control signal 1115 in TTIn. Once a wide radio forward bandwidth is configured for TTIn+1, programming can return to normal (i.e., without preprogramming) for subsequent TTIs. For example, control signal 1115 at TTIn+4 indicates the utilization of data resources 1335 at TTIn+4. As a further example, control signals 1115 at TTIn+2 and TTIn+3 indicate that there is no data at the respective TTI, so the receiver bandwidth remains narrow and the receiver can transition to a micro-state. sleep.

[0096] FIG. 14 illustrates another 1410 frame format. When this 1410 frame format is used, the center frequency may not remain the same regardless of TTI. This frame format facilitates the use of a receiver that can vary its center frequency and RF front-end bandwidth. The receiver bandwidth envelope is indicated.

[0097] The bandwidth of a receiver is centered on a frequency at the center of the control signal 1415 in TTIn and then the center is shifted during the transition period 1420 to the frequency at the center of the data signal 1445.

[0098] This frame format 1410 combined with the pre-programming of data signals 1445, 1455 and 1465 using control signal 1415 implies that control signals 1425 can be ignored by a receiver configured to receive data signals 1445, 1455 and 1465. As illustrated in Fig. 14 programming fractional TTIs for data signals can be realized. For example, data signals 1445 and 1465 occupy a fraction of a TTI time slot, and the duration of the data signals may be indicated by control signal 1415. After data signal 1465, the RF front end may be retuned to a bandwidth for the control signal 1435 during the transition period 1430.

[0099] FIG. 15 illustrates another frame format 1510. Frame format 1510 is an example of a TDM format in which control signals and data signals are received by a UE, and acknowledgment messages (ACKs) are transmitted by the UE in response to the reception of data signals. In one embodiment, an ACK is used to indicate whether all or part of a preceding data signal was received correctly. In this 1510 frame format, the RF front end bandwidth of a receiver is maintained at the system bandwidth or maximum available data bandwidth until a TTI that does not have a data allocation is received. For example, in TTIn+2, the control signal 1535 indicates that there is no data in the TTI, so a receiver may reduce its bandwidth during the transition period 1530, as shown. Guard periods can be inserted on either side of an ACK. For example, guard periods 1544 and 1546 are inserted on both sides of ACK 1445.

[0100] An exemplary embodiment of programming data signals according to frame format 1510 is as follows. The control signal 1515 in TTIn can be used to schedule the data signal 1565 for a fraction of the TTI. After receiving the control signal 1515, a receiver transitions its RF front end bandwidth to receive the data signal 1565 as shown. Alternatively (not illustrated), control signal 1515 in TTIn may carry bandwidth switch indicator or preprogramming information, similar to the scheme described in Fig. 11, and data assignment is deferred until TTIn+i. This scheme avoids allocating data RBs for only a fraction of TTI (as in 1565), at the expense of delayed start for data transfer. Then, the RF front end bandwidth is maintained at a wide bandwidth until a control signal on a TTI indicates that there is no data on the TTI. The narrowband control signal 1525 indicates that the data signal 1575 is present, whereby the receiver is configured to receive the data signal. The control signal 1525 may utilize a subset of the available subcarriers and the portion of the data signal 1575 that is simultaneous with the control signal 1525 may occupy the remaining available subcarriers. The control signal 1535 indicates that there is no data in TTIn+2, whereby the receiver reduces its RF front end bandwidth and may also transition to a microsleep state during the transition period 1530.

[0102] Some advantages of the 1510 frame format include the following. Firstly, for consecutive TTI data allocation, since the overhead is paid by widening the RF bandwidth (causing delay in the start of data radio blocks), in the subsequent TTI there is no block overhead data radio. Secondly, enhancements for wideband to narrowband transitions, such as a countdown timer or bandwidth switch indicator described in relation to Fig. 12, could also be applied.

[0102] FIG. 16 illustrates another frame format 1610. Frame format 1610 is an example of a TDM format in which control signals and data signals are received by a UE and ACKs are transmitted by the UE in response to receiving data signals. An exemplary embodiment of programming data signals according to frame format 1610 is as follows. The control signal 1615 in TTIn can be used to schedule the data signal 1620 for a fraction of the TTI. After receiving the control signal 1615, a receiver transitions its RF front end bandwidth to receive the data signal 1620 as shown. The receiver switches back to a narrow bandwidth for reception of each control signal as shown. For example, the receiver transitions to a narrow bandwidth during the transition period 1640 and then receives the control signal 1625 using a narrow bandwidth as shown. An advantage of the 1610 frame format may include that the bandwidth switching behavior is the same across TTIs.

[0103] Once it is appreciated how the frame formats in Fig. 3 and 5 can be implemented using the adjustable receiver 200 as described previously, it is readily understood that the frame formats in Figs. 1116 can be implemented in a straightforward manner using the adjustable receiver 200.

[0104] The various illustrative blocks and modules described in connection with the present description may be implemented or executed with a general purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, components of discrete hardware or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other similar configuration).

[0105] The functions described here can be implemented in hardware, software executed by a processor, firmware or any combination thereof. If implemented in software executed by a processor, functions may be stored or transmitted through one or more instructions or code in a computer-readable medium. Other examples and implementations are within the scope of the description and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software running by a processor, hardware, firmware, hardware, or combinations of any of these. Resource implementation functions may also be physically located in multiple locations, including being distributed so that parts of functions are implemented in different physical locations. Also, as used herein, including in the claims, "or" as used in a list of items (e.g., a list of items prefaced by a phrase such as "at least one of or" one or more of) By For example, a list of [at least one of A, B, or C] means A or B or C or AB or AC or BC or ABC (that is, A and B and C).

[0106] As those skilled in the art will now appreciate and depending on the particular application at hand, many modifications, substitutions and variations may be made in the materials, apparatus, configurations and methods of using the devices of the present disclosure without departing from the spirit and scope of the same. In view of this, the scope of the present description should not be limited to that of the particular embodiments illustrated and described in the present specification, as they are merely by way of a few examples thereof, but, on the contrary, should be fully commensurate with the claims attachments and their functional equivalents.

Claims (11)

1. A wireless communication method, comprising: transmitting a control signal to a mobile device using a first bandwidth; and transmitting a data signal to the mobile device using a second bandwidth wider than the first bandwidth, wherein the control signal and the data signal are transmitted over a single carrier frequency, wherein the signal method comprises an indication of a characteristic of the data signal, and wherein the data signal is transmitted after the control signal such that the data signal and the control signal are separated by a time interval, the method characterized by the fact that the time interval is based on a switching latency of the mobile device. 2. Method according to claim 1, characterized in that the indication indicates that the second bandwidth completely occupies an available bandwidth. 3. Method according to claim 1, characterized in that the indication indicates that the second bandwidth occupies only a portion of an available bandwidth. 4. Method according to claim 1, characterized by the fact that it further comprises: transmitting a second control signal using the second bandwidth, wherein the second control signal indicates that there is no subsequent data signal before a third control signal; and transmitting the third control signal using the first bandwidth. 5. The method of claim 1, wherein the second control signal comprises a control signal portion and a data signal portion. 6. The method of claim 1, further comprising transmitting a second data signal to the mobile device using a third bandwidth over the single carrier frequency, wherein the third bandwidth is wider than the first bandwidth and different from the second bandwidth. 7. The method of claim 1, further comprising: receiving a capability message from the mobile device, wherein the capability message comprises an indication of the device's dynamic bandwidth switching capability. mobile; transmit a response message comprising an indication that dynamic bandwidth switching is activated. 8. The method of claim 7, wherein the capability message further comprises an indication of switching latency of the mobile device, and wherein the method further comprises: determining the time interval between the control signal and the data signal based on the switching latency indication, wherein the response message further comprises an indication of the time interval. 9. The method of claim 1, further comprising transmitting a second data signal to a second mobile device using a second unique carrier frequency, wherein the second carrier frequency is different from the single carrier frequency and in that the second data signal overlaps in time with the data signal and does not overlap in frequency with the data signal. 10. Memory characterized by the fact that it comprises instructions stored therein which, when executed by a computer, carry out a method as defined in any one of claims 1 to 9. 11. Wireless communication apparatus characterized by the fact that it comprises means for carrying out a method as defined in any one of claims 1 to 9.