Patent Description:
A communication device, which may be used for wired and wireless communications, may be a base station or other electronic device. Such a communication device may have a transceiver that receives and transmits signals over different frequency bands. The transceiver may be implemented as a receiver and a transmitter. A typical receiver may be designed to process signals in accordance with any suitable protocol and standard, such as time division multiple access (TDMA), frequency division multiple access (FDMA) or code division multiple access (CDMA), among others.

There is increasing demand for more flexible spectrum band access and greater system capacity to support multiple access over a greater number of receiving paths. This poses a higher pressure on hardware resources, requiring better power efficiency and processing speed within a communication device. There are also cost considerations. For example, providing a receiver with a high number of receiving (Rx) paths (e.g., up to <NUM>-<NUM> Rx paths) using conventional receiver architecture may be costly.

<CIT> discloses an apparatus and method for mixed signal spread spectrum receiving and spectrum aggregation in a receiver having at least one antenna receiving at least one signal. The method includes modulating the at least one signal received by the receiver with at least one pseudorandom code, down-converting the at least one modulated signal into at least one baseband signal.

<CIT> discloses a receiver that includes a RF processing module for down-converting and multiplexing received signals and a baseband processing module for converting the signals into digital signals, generating code sequence, and producing despreaded and demultiplexed in phase signals, and retrieving data initially contained in the received signals.

<CIT> discloses Pseudo-noise carrier suppression/image rejection up and down converters.

Accordingly, it would be useful to provide a solution for processing RF signals over different frequency bands, with lower system hardware costs.

Embodiments not falling within the scope of the claims are exemplary only.

In some examples, the present disclosure describes an apparatus and a receiver used to receive and process RF analog signals using pseudo-noise (PN) complex codes. The PN complex codes are orthogonal with respect to each other. Each PN complex code may be filtered to remove or reduce negligible undesired harmonics. Each PN complex code is modulated using complex modulation. A PN encoder on each receiving path may use the PN complex code to encode a respective received analog signal, in order to perform analog spreading and down-conversion on the received analog signal in one step. This may help to decrease hardware cost and receiver complexity, for example by at least one of enabling sharing of hardware resources among Rx paths and avoiding the need for a separate down-conversion stage.

For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:.

In a radio frequency (RF) communication network, it may be desirable to provide a communication device that has a receiver with capacity to support multiple access over different frequency bands. Example methods and apparatuses are described below, which may help to improve performance in receivers supporting multiple access, with relatively low hardware requirements.

To assist in appreciating the disclosed methods and systems, examples of conventional receivers are first discussed. A conventional receiver <NUM> is shown in <FIG>. The receiver <NUM>, as well as other receivers discussed below, may be implemented in any communication device, including devices for wired or wireless communications, such as an electronic device such as a base station or a user equipment (UE) for use in a wireless communication network, for example a Fifth Generation (<NUM>) wireless communication network. Although examples may be described below in the context of wireless communications (e.g., using antennas to receive RF analog signals), it should be understood that the present disclosure may also be implemented for wired communications.

The receiver <NUM> includes a plurality of RF receiving (Rx) paths <NUM>(<NUM>) to <NUM>(n) (generically referred to as Rx path <NUM>). For clarity, one Rx path <NUM>(<NUM>) is indicated by a dashed box. Each Rx path <NUM> includes at least one antenna <NUM>, a band pass filter (BPF) <NUM>, a low noise amplifier <NUM> (LNA), a down converter <NUM>, a low pass filter (LPF) <NUM>, and an analog to digital converter (ADC) <NUM>. One Rx path <NUM> will be discussed in detail as an example. A RF analog signal is received by the antenna <NUM>. In some examples, an antenna array may be used instead of a single antenna. The received signal is filtered by the BPF <NUM>. The filtered signal is then provided to the LNA <NUM> where the signal is amplified to an amplitude suitable for subsequent processing. The amplified signal from the LNA <NUM> is provided to the down converter <NUM> to be down-converted to an intermediate frequency (IF) (or baseband frequency) using a local oscillator (LO) signal. The IF signal is then passed through the LPF <NUM>. The output of the LPF <NUM> is provided to the ADC <NUM>. The ADC <NUM> converts the filtered IF signal into a digital signal. Digital signals from each of the plurality of Rx paths <NUM> (in this example, the n digital signals from the n Rx paths Rx1 to Rxn) are then provided to a decoder <NUM> to generate decoded digital signals Rx1_o to Rxn_o. The decoded digital signals may then be supplied to other components of the receiver <NUM>, such as a digital signal processor (DSP).

Although the receiver <NUM> is capable of processing multiple spectrum bands with different frequencies, the conventional architecture of the receiver <NUM> does not share hardware resources among the Rx paths <NUM>. As well, single or multi-stage down converters <NUM> are included in each Rx path <NUM>. This means that increasing the number of RF Rx paths would incur high hardware cost, increase overall circuitry complexity, require greater computation power and take up more printed circuit board (PCB) area in the communication device.

Another example conventional receiver <NUM> is shown in <FIG>. In this example receiver <NUM>, hardware costs may be reduced compared to the example receiver <NUM> of <FIG>, because the receiver <NUM> uses a single ADC, rather than separate ADCs for each Rx path. The receiver <NUM> includes a plurality of RF Rx paths <NUM>(<NUM>) to <NUM>(n) (generically referred to as Rx path <NUM>). For clarity, one Rx path <NUM>(<NUM>) is indicated by a dashed box. Each Rx path <NUM> includes at least one antenna <NUM>, a BPF <NUM>, a LNA <NUM>, a down converter <NUM>, and a BPF <NUM>. A RF analog signal is received by the antenna <NUM> and is processed by the BPF <NUM> and the LNA <NUM>, similarly to that described above with respect to <FIG>. The output of the LNA <NUM> is provided to the down converter <NUM>.

Unlike the example receiver <NUM> of <FIG>, in the example receiver <NUM> of <FIG>, each down converter <NUM> performs down conversion using a different respective LO signal, indicated as LO1 to LOn. The down conversion serves to perform frequency translation, which maps the input RF signals to different respective IF frequencies, according to the frequencies of the respective LO signals. The IF analog signal outputted from the down converter <NUM> is passed through the BPF <NUM>. The filtered analog signals from the Rx paths <NUM> can then be orthogonally combined by a combiner <NUM> into a single analog signal, without mixing up the signals. Therefore, a single ADC <NUM> can be used to convert the combined RF analog signal into a combined digital signal. The combined digital signal is then decoded by a decoder <NUM> to output n digital outputs Rx1_o to Rxn_o (corresponding to n Rx paths <NUM>), which may be provided to other components of the communication device.

In the example shown in <FIG>, because a single ADC <NUM> is shared by the plurality of Rx paths, the hardware cost may be reduced compared to the example shown in <FIG>. However, the example system <NUM> of <FIG> still requires a down converter <NUM> in each Rx path <NUM>.

<FIG> illustrates a conventional receiver <NUM> that uses orthogonal spreading codes, such as pseudo-noise (PN) codes, to reduce hardware costs. The receiver <NUM> includes a plurality of RF Rx paths <NUM>(<NUM>) to <NUM>(n) (generically referred to as Rx path <NUM>). For clarity, one Rx path <NUM>(<NUM>) is indicated by a dashed box. Each Rx path <NUM> includes at least one antenna <NUM>, a BPF <NUM>, a LNA <NUM>, a down converter <NUM>, and a BPF <NUM>. These components receive and process a RF analog signal similarly to the counterparts described above with respect to <FIG>. In the receiver <NUM>, each Rx path <NUM> further includes a PN encoder <NUM> coupled to the BPF <NUM>. The PN encoder <NUM> encodes the filtered IF analog signal outputted from the BPF <NUM>, using a PN code, over in-phase (I) and quadrature-phase (Q) branches, resulting in a PN-encoded I signal (which may also be referred to as the I component of a PN-encoded signal) and a PN-encoded Q signal (which may also be referred to as the Q component of the PN-encoded signal). A different respective PN code is used by the PN encoder <NUM> in each Rx path <NUM>. The mutually orthogonal PN codes PN1 to PNn are generated by a PN code generator <NUM>.

The PN-encoded I signals from the plurality of RF Rx paths <NUM>(<NUM>) to <NUM>(n) are combined by a I combiner <NUM> into an I combined analog signal, and the PN-encoded Q signals are combined by a Q combiner <NUM> into a Q combined analog signal. An ADC <NUM> then converts the I combined analog signal to an I combined digital signal, and an ADC <NUM> converts the Q combined analog signal to a Q combined digital signal. A decoder <NUM> decodes the I and Q combined digital signals to n digital outputs Rx1_o to Rxn_o (corresponding to the n Rx paths <NUM>), and the decoded digital outputs may be provided to other components of the communication device.

In the receiver <NUM>, the mutual orthogonality of the PN codes enables PN-encoded signals from a plurality of RF Rx paths to be combined and later recovered. However, using PN codes to modulate RF analog signals in the Rx paths may introduce undesired harmonics and images. The term "images" refers to frequency products that are unintentionally produced when a signal is modulated up or down in frequency, due to the nonlinear nature of a mixer. The introduction of undesired harmonics and images, which negatively impact device performance, means that additional processing of the signals is required to avoid distortion.

A receiver, as disclosed herein, may help to improve device performance over multiple spectrum bands and reduce system hardware cost, and may address at least some drawbacks of the above-discussed conventional receivers. The disclosed receiver may be used in various applications, including in communication devices capable of multiple access in wireless communication networks. Although described in the context of a receiver, aspects of the present disclosure may also be implemented as an apparatus that provides PN complex codes and performs PN encoding, as discussed further below.

<FIG> shows an example disclosed receiver <NUM>. The receiver <NUM> uses PN complex codes to perform spreading and down conversion in a single stage in each Rx path, in accordance with an example embodiment. The receiver <NUM> may help to improve overall device performance and reduce overall device cost, compared to conventional receivers that use down converters in the Rx paths. As presented in <FIG>, the receiver <NUM> includes a plurality of Rx paths <NUM>(<NUM>) to <NUM>(n) (generally referred to as Rx paths <NUM>) on which RF analog signals are received and processed. For clarity, one Rx path <NUM>(<NUM>) is indicated by a dashed box. Although described in the context of wireless communications, it should be understood that the receiver <NUM> may be used (with appropriate modifications where necessary) for wired communications. For example the Rx paths <NUM> may receive RF analog signals from a wired source rather than a wireless source. For simplicity, the receiver <NUM> will be described below in the context of wireless communications.

In one Rx path <NUM>, an antenna <NUM> (or antenna array) receives an RF analog signal. The RF analog signal received by the antenna <NUM> is filtered by a BPF <NUM>. The filtered signal from the BPF <NUM> is provided to a LNA <NUM> to amplify the low power signal to a desired amplitude. Then a PN encoder <NUM> encodes the amplified signal using a PN complex code and outputs a PN-encoded analog signal. The PN encoder uses the PN complex code to perform analog signal spreading and down-conversion, in a single step. A different PN complex code is used for PN encoding in each respective Rx path <NUM>. The PN complex codes are mutually orthogonal. Each PN complex code may have been filtered (e.g., using a filter as discussed further below) to remove or reduce undesired harmonics. The PN complex codes are centered at a code modulation frequency by complex modulation, such that fold-in images are not generated during the complex modulation. Details about generation of the filtered PN complex code will be discussed further below.

In the example of <FIG>, the PN encoder <NUM> is an I and Q encoder (also referred to as an I/Q encoder), which performs PN encoding using a PN complex code over I and Q branches. In other examples, the PN encoder <NUM> may be a real encoder that outputs an encoded signal having only a real component. The I/Q encoder <NUM> outputs a PN-encoded I analog signal (also referred to as the I component of a PN-encoded analog signal) and a PN-encoded Q analog signal (also referred to as the Q component of a PN-encoded analog signal). When distinct information signals are separately processed over I and Q branches, this effectively doubles the number of channels operating within the receiver. The PN-encoded I signal and the PN-encoded Q signal are filtered by LPFs <NUM>(a) and <NUM>(b), respectively. The output from each Rx path <NUM> is a filtered PN-encoded I analog signal and a filtered PN-encoded Q analog signal.

An I combiner <NUM> combines the filtered PN-encoded I analog signals from the plurality of Rx paths into a I combined analog signal, and a Q combiner <NUM> combines the filtered PN-encoded Q analog signals from the plurality of Rx paths into a Q combined analog signal. An ADC <NUM> converts the I combined analog signal and outputs an I combined digital signal, and an ADC <NUM> converts the Q combined analog signal and outputs a Q combined digital signal. An I and Q decoder <NUM> (also referred to as an I/Q decoder) decodes the I combined digital signal and Q combined digital signal to a plurality of decoded digital outputs. The plurality of decoded digital outputs may be provided to other components of the communication device, such as a digital processor (not shown).

In the example of <FIG>, the I/Q encoder <NUM> outputs PN-encoded I and Q analog signals, which may be separately processed by separate I and Q combiners <NUM>, <NUM> and ADCs <NUM>, <NUM>. In other examples, the encoder <NUM> may be a real encoder. In such examples, a single combiner may be used instead of separate I and Q combiners <NUM>, <NUM>. One LPF may be used instead of separate LPFs <NUM>(a), <NUM>(b), and a single ADC may be used instead of two ADCs <NUM>, <NUM> to output one combined digital signal. Moreover, the decoder <NUM> may decode the combined digital signal over the real channel. Encoding and processing a complex signal may provide advantages compared to encoding and processing a real signal, as discussed further below.

In the example shown in <FIG>, the receiver <NUM> includes a PN complex code source <NUM> to provide the PN complex codes, and a controller <NUM> for controlling the operation of the PN complex code source <NUM> and the decoder <NUM>. The PN complex code source <NUM> and the controller <NUM> are described in more detail further below. In some examples, the receiver <NUM> may not include either or both of the PN complex code source <NUM> and the controller <NUM>. For example, the PN complex codes may be generated by an external component and provided to the receiver <NUM>. In some examples, external control signals may be used to control the operation of the decoder <NUM>, or control signals may not be needed.

In the disclosed receiver <NUM>, using mutually orthogonal PN complex codes to encode received analog signals enables combining of signals from a plurality of RF Rx paths, thus allowing for sharing of hardware components among the Rx paths. The disclosed receiver <NUM> avoids the use of multi-stage down converters. As well, using PN complex codes, rather than conventional PN codes, helps to reduce or eliminate undesired harmonics and images in the encoded signals, as will be discussed further below.

The process of generating the mutually orthogonal PN complex codes and performing encoding using a respective PN complex code on each Rx path is now discussed in greater detail with reference to <FIG>. For simplicity, the LPFs <NUM>(a), <NUM>(b) downstream of the PN encoder <NUM> are not shown in <FIG>. As mentioned above, the receiver <NUM> may include the PN complex code source <NUM> to provide a respective PN complex code for use by the PN encoder <NUM> on each respective Rx path <NUM>. The number of PN complex codes provided by the PN complex code source <NUM> corresponds to the number of Rx paths <NUM> being used. The PN complex code source <NUM>, in this example, includes a code generator <NUM>, a filter <NUM>, and a complex modulator <NUM>. The code generator <NUM> generates a plurality of mutually orthogonal codes <NUM>. The number of codes <NUM> generated corresponds to the number of Rx paths <NUM> being used. The generated codes <NUM> are unfiltered and unmodulated PN codes. In some example embodiments, the plurality of codes <NUM> may be generated by the code generator <NUM> in parallel. In some example embodiments, one or more parameters (such as any one or more of code type, code length, and code rate) for generating the mutually orthogonal codes are variable and may be controlled by a control signal (e.g., a control signal from the controller <NUM> or an external control signal). The parameter(s) for generating the mutually orthogonal codes may be selected to achieve desired performance characteristics, as discussed further below.

The mutually orthogonal codes <NUM> are provided to the filter <NUM> to filter out undesired harmonics of the PN codes. The filter <NUM> may be a low-pass filter or other type of filter (e.g., a band-pass filter) tuned to remove or reduce undesired harmonics. Removal or reduction of undesired harmonics may help to reduce interference and distortion when the PN complex code is used for encoding received analog signals at the PN encoder <NUM>. Outputs of the filter <NUM> may be referred to as filtered PN codes <NUM>. The filtered PN codes <NUM> are then provided to the complex modulator <NUM> for complex modulation. The complex modulator <NUM> modulates each filtered PN code <NUM> to a code modulation frequency using an LO signal. The complex modulation enables each filtered PN code <NUM> to be centered at the code modulation frequency. The outputs of the complex modulator <NUM> are the PN complex codes <NUM> that are provided to the PN encoders <NUM>. In some examples, the filter <NUM> may be omitted. For example, the mutually orthogonal codes <NUM> generated by the code generator <NUM> may already be sufficiently free of undesired harmonics.

<FIG> illustrate examples of the outputs of each stage of the PN complex code source <NUM> described above. <FIG> shows four example unfiltered and unmodulated PN codes (code <NUM> to code <NUM>) that may be generated by the code generator <NUM>. As shown in <FIG>, each unfiltered and unmodulated PN code in this example includes undesired harmonics <NUM>(<NUM>) and <NUM>(<NUM>), which are indicated by dashed ellipses (generically referred to as undesired harmonics <NUM>). Each PN code is filtered by the filter <NUM> (e.g., a low-pass filter) to filter out the undesired harmonics <NUM> and output a respective filtered PN code <NUM>. <FIG> shows the four example filtered PN codes, with undesired harmonics filtered out by the filter <NUM>. The complex modulator <NUM> then modulates the center frequency of each filtered PN code to a code modulation frequency. <FIG> shows the four filtered and modulated PN codes, with center frequencies modulated from <NUM> to around -<NUM> by the complex modulator <NUM>.

In some example embodiments, the complex modulator <NUM> may be implemented using a multiplier, which multiplies each filtered PN code with the LO signal over the time domain, to modulate the filtered PN code to the desired code modulation frequency.

Modulating each filtered PN code using complex modulation may help to avoid or reduce the production of undesired fold-in images. The complex modulation of the PN codes results in negligible or no fold-in images, whereas real modulation can result in significant fold-in images. By reducing or eliminating the production of fold-in images, complex modulation of the filtered PN codes may help to reduce inter-modulation components when the filtered and modulated PN codes are used for encoding each received signal, and this may help to improve device performance.

Reference is made to <FIG> again. As discussed above, the receiver <NUM> may use an I/Q encoder <NUM> to encode the RF analog signal. Generally, complex encoding of the RF analog signal may help to improve overall device performance compared to real encoding, due to the avoidance of fold-in images as discussed above. In the example shown in <FIG>, the I/Q encoder <NUM> includes a splitter <NUM>, first and second multipliers <NUM>, <NUM>, and first and second LPFs <NUM>, <NUM>. The splitter <NUM> splits the RF analog signal from the LNA <NUM> to an I analog signal and a Q analog signal.

The I analog signal is encoded by an I component <NUM>(<NUM>) of the PN complex code using the first multiplier <NUM>. The first LPF <NUM> may then filter the PN-encoded I analog signal. Similarly, the Q analog signal is encoded by a Q component <NUM>(<NUM>) of the PN complex code using the second multiplier <NUM>, and subsequently may be filtered by the second LPF <NUM>.

Reference is made to <FIG> again. As discussed previously, in some example embodiments, a controller <NUM> may be included within the receiver <NUM>. The controller <NUM> may provide instructions to control operation of any one or more of the Rx paths <NUM> and the PN complex code source <NUM>, for example to support one or both of multiple spectrum access and different signal bandwidths. In some example embodiments, the PN complex code source <NUM> may receive instructions to set one or more parameters, such as any or all of code type, code length, and code rate, for generation of mutually orthogonal codes. In some example embodiments, a signal bandwidth (such as <NUM>, <NUM>, etc.) supported by the receiver <NUM> for transmission may be variable by varying the code rate. In some example embodiments, the PN complex code source <NUM> may receive instructions to set the code modulation frequency to which the filtered PN code is modulated.

In some example embodiments, the number of Rx paths <NUM> that are used by the receiver <NUM> may be selected from a total number of available Rx paths at the receiver <NUM>, and may be variable. For example, all available Rx paths <NUM> may be used, such that RF analog signals are received and processed by all available Rx paths <NUM>. In other examples, only a subset of all available Rx paths <NUM> may be selected for use, and unselected Rx paths do not receive or process RF analog signals. Any Rx path may be set to be used or not used, at any time, by control signals (e.g., control signals from the controller <NUM>, or external control signals). The ability to control the number of Rx paths <NUM> that are used by the receiver <NUM> may help to more efficiently use the resources of the communication device.

In some examples, a controller external to the receiver <NUM> (e.g., another controller or processor within the communication device) may provide instructions to the receiver <NUM> instead of, or in addition to, the controller <NUM> that is internal to the receiver <NUM>.

<FIG> are simulation plots showing how an RF analog signal is processed and converted to a digital signal using a PN complex code, in the example receiver <NUM>. In these simulations, four RF Rx paths are used, the PN code length is four, the signal bandwidth is <NUM>, and a carrier frequency is <NUM>. The RF analog signals are received by the four RF Rx paths within the receiver <NUM>. <FIG> shows an analog signal received on one Rx path <NUM>. <FIG> shows the combined PN-encoded analog signal after the analog signal of <FIG> has been encoded by the I/Q encoder <NUM> using a PN complex code and combined. It should be noted that the I and Q components of the combined PN-encoded signal are not plotted separately in <FIG>. <FIG> shows the decoded digital signal <NUM> that is expected (i.e., the ideal theoretical output) after decoding the encoded signal of <FIG>. <FIG> also shows an error <NUM> between the expected decoded digital output and the actual decoded digital output from the decoder <NUM>. <FIG> shows that, in this example, the error is negligible. This means that the disclosed receiver <NUM> provides decoded digital output that is sufficiently close to the expected decoded digital output.

In the disclosed example receiver <NUM>, by encoding the RF analog signal with PN complex codes, analog spreading and down conversion may be performed in a single stage at the PN encoder, rather than using multiple down converters and filters as in a conventional receiver. This simplification may help to either or both of reduce hardware cost and improve device performance, and may avoid significant interference and distortion of the signals. Degradation in device performance caused by phase noise and jitter may be reduced significantly by using PN complex codes for PN encoding. Using PN complex codes enables the plurality of RF Rx paths to share hardware resources, and may also reduce or eliminate undesired harmonics, thus improving device performance. Furthermore, production of undesired fold-in images is avoided by using complex modulation for generating the PN complex codes.

It will be appreciated that one or more components discussed above on each RF Rx path <NUM> may be made of basic electronic components. For example, any or all of the BPF <NUM> and any of the filters <NUM>(a), <NUM>(b), <NUM>, and <NUM> may be resistor-inductorcapacitor (RLC) circuits. Any or all of LNA <NUM>, the modulator <NUM>, the I/Q encoder <NUM>, the I combiner <NUM>, the Q combiner <NUM>, the ADCs <NUM>, <NUM>, PN code generator <NUM>, and the complex modulator <NUM> may be implemented using any suitable transistors or integrated circuits.

It should be understood that aspects of the present disclosure may be implemented as an apparatus that includes the PN encoder <NUM> and PN complex code source <NUM> as described above. The apparatus may be in general any receiver including the PN encoder <NUM> and PN complex code source <NUM> as described above, and may have other components different from those described above with reference to <FIG>. For example, components on the Rx path <NUM>, such as any or all of the BPF <NUM>, LNA <NUM> and LPFs <NUM>(a), <NUM>(b) may be varied or omitted.

<FIG> is a schematic diagram of an example wireless communication device <NUM>, which may be used to implement the methods and systems disclosed herein. For example, the wireless communication device <NUM> may be an electronic device, such as a user equipment (UE) or a base station used in <NUM> communication networks, and may include a receiver <NUM> as disclosed above. Other communication devices (including communication devices for wired or wireless communications) suitable for implementing examples described in the present disclosure may be used, which may include components different from those discussed below. Although <FIG> shows a single instance of each component, there may be multiple instances of each component in the wireless communication device <NUM> and the wireless communication device <NUM> could be implemented using one of both of a parallel and a distributed architecture.

The wireless communication device <NUM> may include one or more processing devices <NUM>, such as a processor, a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a dedicated logic circuitry, or combinations thereof. The wireless communication device <NUM> may also include one or more optional input/output (I/O) interfaces <NUM>, which may enable interfacing with one or more of optional input devices <NUM> and output devices <NUM>. The wireless communication device <NUM> may include one or more network interfaces <NUM> for wired or wireless communication with a network (e.g., any one or more of an intranet, the Internet, a P2P network, a WAN, a LAN, and a Radio Access Network (RAN)) or other node. The network interface(s) <NUM> may include one or more interfaces to wired networks and wireless networks. Wired networks may make use of wired links (e.g., Ethernet cable). Wireless networks, where they are used, may make use of wireless connections transmitted over an antenna such as antenna <NUM>. The network interface(s) <NUM> may provide wireless communication via one or more transmitters or transmit antennas and one or more receivers or receive antennas, for example. In this example, one antenna <NUM> is shown, which may serve for both transmitter and receiver. However, in other examples there may be multiple antennas for transmitting and receiving. In some examples, an antenna array may be used. The wireless communication device <NUM> may also include one or more storage units <NUM>, which may include a mass storage unit such as any one of more of a solid state drive, a hard disk drive, a magnetic disk drive and an optical disk drive.

The wireless communication device <NUM> may include one or more memories <NUM> that can include physical memory <NUM>, which may include a volatile or non-volatile memory (e.g., any one or more of a flash memory, a random access memory (RAM), and a readonly memory (ROM)). The non-transitory memory(ies) <NUM> (as well as storage <NUM>) may store instructions for execution by the processing device(s) <NUM>, such as to carry out processing such as those described in the present disclosure. The memory(ies) <NUM> may include other software instructions, such as for implementing an operating system (OS), and other applications/functions. In some examples, one or both of data sets and modules may be provided by an external memory (e.g., an external drive in wired or wireless communication with the wireless communication device <NUM>) or may be provided by a transitory or non-transitory computer-readable medium. Examples of non-transitory computer readable media include a RAM, a ROM, an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a CD-ROM, or other portable memory storage.

There may be a bus <NUM> providing communication among components of the wireless communication device <NUM>. The bus <NUM> may be any suitable bus architecture including, for example, a memory bus, a peripheral bus or a video bus. Optional input device(s) <NUM> (e.g., one or more of a keyboard, a mouse, a microphone, a touchscreen, and a keypad) and optional output device(s) <NUM> (e.g., one or more of a display, a speaker and a printer) are shown as external to the wireless communication device <NUM>, and connected to optional I/O interface <NUM>. In other examples, either or both of one or more of the input device(s) <NUM> and one or more of the output device(s) <NUM> may be included as a component of the wireless communication device <NUM>.

The apparatus or receiver described above may be included as a component of the wireless communication device <NUM>, for example as a component in the signal path for receiving RF analog signals using multiple antennas <NUM>. The processing device(s) <NUM> may also be used to control processing the received RF analog signal and generation of PN complex codes. For example, one or more functions of the controller <NUM> described above may be performed by the processing device(s) <NUM>.

<FIG> illustrates an example method that may be implemented using the PN complex code source <NUM> described above to provide mutually orthogonal PN complex codes for PN encoding of received RF analog signals by the PN encoder <NUM>.

The method includes, optionally, at <NUM>, receiving instructions to generate a plurality of PN complex codes. The instructions may be received from at least one of a source internal to the receiver <NUM> (e.g., from the controller <NUM>) and a source external to the receiver <NUM> (e.g., from a processing device <NUM> of the wireless communication device <NUM>). In some example embodiments, the instructions may control a variable parameter, such as at least one of a code type, a code length and acode rate, for generating mutually orthogonal codes. In some examples, the instructions may control a variable code rate in order to achieve a signal bandwidth that the receiver is required to support. In some examples, the instructions may indicate the code modulation frequency for modulation of individual codes.

At <NUM>, a plurality of mutually orthogonal codes is generated. The codes are generated in accordance with the received instructions, in examples where such instructions were received at <NUM>. The plurality of mutually orthogonal codes may be generated by the above-described PN code generator <NUM> of the PN complex code source <NUM>.

At <NUM>, according to the claimed invention, undesired harmonics of the mutually orthogonal codes are filtered out. In some examples, as illustrated above, undesired harmonics may be filtered out using a filter <NUM> in the PN complex code source <NUM>.

At <NUM>, the mutually orthogonal codes are modulated to a code modulation frequency. In some example embodiments, the code modulation frequency to which each code is modulated may be variable in accordance with the instructions received at <NUM>. The modulation may be performed by the complex modulator <NUM> in the PN complex code source <NUM>.

At <NUM>, each PN complex code is provided to the PN encoder of each respective Rx path, to perform PN encoding of the received analog signals. The number of PN complex codes corresponds to the number of Rx paths being used to receive analog signals, as discussed above.

In the present disclosure, example apparatus and receiver are described. By encoding signals using PN complex codes in the analog domain, the examples disclosed herein may perform both down-conversion and analog spreading simultaneously, which may reduce system hardware costs compared to conventional receivers. Further, the disclosed apparatus and receiver provide flexibility in how the RF analog signal is processed, by enabling software control of variable parameters. The example disclosed apparatus and receiver may introduce little or no negative interference and distortion to the received signals because undesired harmonics and fold-in images are avoided.

In various examples, using the PN complex code for complex encoding of the received RF analog signals may also help to improve system performance compared to real encoding.

The example disclosed receiver may be used in electronic devices, such as UEs and base stations, for example in a <NUM> communication system, to boost system performance, particularly for operation on various spectrum bandwidth with massive system capacity. Furthermore, the disclosed apparatus and receiver may have little or no negative impact on efficiency and power consumption of the device by performing down conversion and spreading simultaneously at a single stage. The hardware cost of the example disclosed receiver may be lower, compared to a conventional receiver.

In some examples, the disclosed apparatus and receiver may support multiple spectrum band access for MIMO system without using band frequency selection or band filter bank. The receiver may be flexibly controlled to vary at least one parameter for generating a PN code. The receiver may also enable a plurality of RF Rx paths to share hardware resources flexibly. Moreover, the number of Rx analog paths, signal bandwidth, and code modulation frequency may be varied to enable the receiver to receive and process multiple spectrum bands over various frequencies. Thus, the flexibility of the receiver may be increased without significant increase to the complexity in the circuitry design. The disclosed apparatus and receiver may provide a greater degree of freedom to design for supporting massive wireless communication system for MIMO technology without significantly increasing hardware cost.

Although the present disclosure describes methods and processes with steps in a certain order, one or more steps of the methods and processes may be omitted or altered as appropriate. One or more steps may take place in an order other than that in which they are described, as appropriate.

Although the present disclosure is described, at least in part, in terms of methods, a person of ordinary skill in the art will understand that the present disclosure is also directed to the various components for performing at least some of the aspects and features of the described methods, be it by way of hardware components, software or any combination of the two. Accordingly, the technical solution of the present disclosure may be embodied in the form of a software product. A suitable software product may be stored in a pre-recorded storage device or other similar non-volatile or non-transitory computer readable medium, including DVDs, CD-ROMs, USB flash disk, a removable hard disk, or other storage media, for example. The software product includes instructions tangibly stored thereon that enable a processing device (e.g., an onboard processor, a personal computer, a server, or a network device) to execute examples of the methods disclosed herein.

Claim 1:
An apparatus for encoding a plurality of received radio frequency (RF) analog signals, the apparatus comprising:
a plurality of pseudo-noise, PN, encoders (<NUM>) for performing analog signal spreading and down-conversion, each PN encoder (<NUM>) being configured to encode a respective received RF analog signal using a respective one of a plurality of mutually orthogonal PN complex codes and to output a respective PN-encoded analog signal; and
a PN complex code source (<NUM>) configured to provide the respective mutually orthogonal PN complex codes to the plurality of PN encoders (<NUM>), the PN complex code source (<NUM>) including a code generator (<NUM>) for generating multiple mutually orthogonal PN codes, a filter (<NUM>) configured to filter out undesired harmonics of the multiple mutually orthogonal PN codes, and a complex modulator (<NUM>) for modulating the multiple mutually orthogonal PN codes to generate the mutually orthogonal PN complex codes, wherein the complex modulator (<NUM>) is configured to modulate the center frequency of each filtered mutually orthogonal PN code to a code modulation frequency.