Multiplexing arrangements for multiple receive antennas

Multi-tasking arrangement of multiple receiving antennas

The present disclosure generally relates to communication, and more specifically relates to a technology for wirelessly receiving data packet communication at a plurality of receive (Rx) antennas.

This patent application claims the priority of provisional application No. 61/058,159 filed on June 2, 2008 named "MULTIPLEXING ARRANGEMENTS FOR MULTIPLE RECEIVE ANTENNAS". This is expressly incorporated herein by reference.

Wireless communication systems are widely deployed to provide various types of communication content, such as voice and data. These systems may be multiple access systems capable of supporting communication with multiple users by sharing available system resources (for example, bandwidth and transmission power). Examples of such multiple access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems .

Generally, a wireless multiple access communication system can simultaneously support the communication of multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base station to the terminal, and the reverse link (or uplink) refers to the communication link from the terminal to the base station. This communication link can be established via a single input single output, multiple input single output, or multiple input multiple output (MIMO) system.

Mobile devices increasingly have multiple receiver chains. Each antenna has a radio frequency (RF) front-end amplification and filtering, demodulation, individual digitization and digital decoding. In this way, a mobile device can advantageously monitor multiple base stations, achieve an antenna gain through space diversity, or perform multi-channel communication with the same base station. Although additional operating capabilities are ideal, adding a separate receiving chain increases the size, cost, and complexity of the mobile device. For example, each chain must have a dedicated analog-to-digital converter (ADC) with the necessary pre-filtering, gain control, and post-filtering.

The following presents a simplified summary in order to provide a basic understanding of some of the disclosed aspects. This overview is not an extensive overview and is intended to neither identify important or critical components nor describe the scope of these aspects. Its purpose is to present some concepts of the described features in a simplified form as a prelude to the more detailed description presented later.

According to one or more aspects and their corresponding disclosures, various aspects are described in combination with the analog signals of different receiving antenna (Rx) branches. These different receiving antenna (Rx) branches are preceded by the analog-to-digital converter (ADC). Analog Division Code Multiplexing (ACDM) combination. By appropriately combining the analog signals of each Rx antenna, front-end components such as filters, mixers, and ADC devices can be reduced. The benefits associated with this solution are at least three aspects: the reduced cost, area and power consumption of the multi-antenna terminal. In addition, proper parameter setting improves the signal-to-quantization noise ratio (SQNR) at the ADC output. Using the code division multiplexing (CDM) method to multiplex different analog signals allows the processing of multiple radio frequency (RF) receiver chains to converge into a single chain. Subsequently, the signals are separated digitally by their unique orthogonal codes.

In one aspect, a method for receiving wireless communications at a plurality of receiving antennas is provided. At each of the plurality of antennas, a data packet communication signal modulated on a radio frequency (RF) carrier frequency is received. Processing the received data packet communication signal at the corresponding plurality of receiving chains for each of the plurality of antennas to generate a plurality of analog signals. A sampled and held analog signal is generated for each of the plurality of analog signals. Each sampled and held analog signal is spread by a unique spreading code. Combine each spread-spectrum sampled and held analog signal to generate a single analog signal. A digital version of the single analog signal is generated to generate a combined digital signal. De-spread the digital version to generate a digital copy of each data packet communication signal.

In another aspect, an apparatus for receiving wireless communications at a plurality of receiving antennas is provided. A means for receiving a data packet communication signal modulated on a radio frequency (RF) carrier frequency at each of a plurality of antennas is provided. A means is provided for processing the received data packet communication signal at the corresponding plurality of receiving chains for each of the plurality of antennas to generate a plurality of analog signals. A means for generating a sampled and held analog signal for each of the plurality of analog signals is provided. Provides means for spreading each sampled and held analog signal by a unique spreading code. It provides a means for combining the sampled and held analog signals of each spread spectrum to generate a single analog signal. A means for generating a digital version of the single analog signal to generate a combined digital signal is provided. Provide a component for de-spreading the digital version to generate a digital copy of each data packet communication signal.

In an additional aspect, a device for receiving wireless communications at a plurality of receiving antennas is provided. A plurality of receivers are used to receive data packet communication signals modulated on a radio frequency (RF) carrier frequency. The plurality of receiving chains corresponding to the plurality of antennas are used to process the received data packet communication signal to generate a plurality of analog signals. One of the plurality of sample and hold circuits is used to generate a sampled and held analog signal for each of the plurality of analog signals. A code spread spectrum component is used to spread each sampled and held analog signal by a unique spread spectrum code. A summer is used to combine the sampled and held analog signals of each spread spectrum to generate a single analog signal. An analog-to-digital converter is used to generate a digital version of the single analog signal to generate a combined digital signal. A set of correlators is used to despread the digital version to generate a digital copy of each data packet communication signal.

In order to achieve the foregoing and related objectives, one or more aspects include the features fully described below and specifically pointed out in the scope of the patent application. The following description and accompanying drawings elaborate on specific illustrative aspects and indicate only a few of the various ways in which the principles of these aspects can be used. When considering the drawings in combination, other advantages and novel features will become apparent from the following [Embodiments], and the disclosed aspects are intended to include all these aspects and their equivalents.

When combining the drawings, the features, essence, and advantages of the present disclosure will become apparent from the detailed description set forth below, in which the same reference characters are correspondingly identified throughout the text.

A method and apparatus process a plurality of analog signals in a transceiver with multiple receive (Rx) antennas in a wireless communication system using space diversity. By appropriately combining the analog signals of each Rx antenna, this solution allows a reduction in the number of front-end components such as filters, mixers, and analog-to-digital converter (ADC) devices. Subsequently, the signals are separated digitally by their unique codes. The benefits associated with this solution are at least three aspects: the reduced cost, area, and power consumption of the multi-antenna terminal. In addition, proper parameter settings increase the signal-to-quantization noise ratio (SQNR) at the ADC output.

Now refer to the diagrams to describe the various aspects. In the following description, for explanatory purposes, numerous specific details are set forth to provide a clear understanding of one or more aspects. However, it is obvious that various aspects can be practiced without such specific details. In other cases, well-known structures and devices are shown in block diagram form to facilitate the description of these aspects.

1, the communication system 100 has a transmission entity 102, and the transmission entity 102 transmits respective data packet communication signals 108a, 108b from a plurality of transmission (Tx) antennas 104a, 104b on an air link 106, and the data packets The communication signals 108a, 108b are modulated on a radio frequency (RF) carrier frequency and may (but not necessarily) be separately encoded for spatial diversity. The receiving entity 110 has a plurality of receiving (Rx) antennas 112a, 112b, each of which is connected to a separate receiving chain 114a, 114b that performs RF processing.

For example, the RF front-end 116a, 116b may include the low-noise amplification and filtering used before the respective sample and hold circuits 118a, 118b perform sampling at a rate of at least twice the RF carrier frequency. Alternatively, radio frequency-to-intermediate frequency (RF-IF) demodulators 120a, 120b prepare signals for the respective sample and hold circuits 122a, 122b at a sampling rate that is at least twice the IF. As another alternative embodiment, RF processing may require radio frequency-to-baseband (RF-BB) demodulators 124a, 124b, which are prepared for the respective sample and hold circuits 126a at a sampling rate sufficient for the data rate. , 126b of the received signal.

Each sample and hold analog signal is spread by the unique spreading code mixer 128a, 128b and combined at the summer 130. An analog-to-digital converter (ADC) 132 generates a digital version. The digital version is de-spread by the respective digital correlators 134a, 134b to generate a digital copy of each data packet communication signal.

In Figure 2, a method or sequence 200 of operations for receiving wireless communications at a plurality of receiving antennas is provided. At each of the plurality of antennas, a data packet communication signal that is modulated on a radio frequency (RF) carrier frequency and possibly (but not necessarily) is coded for spatial diversity is received (block 202). The received data packet communication signal is processed at the corresponding plurality of receiving chains for each of the plurality of antennas to generate a plurality of analog signals (block 204). A sampled and held analog signal is generated for each of the plurality of analog signals (block 206). Each sampled and held analog signal is spread by a unique spreading code (block 208). Combine each spread-spectrum sampled and held analog signal to generate a single analog signal (block 210). A digital version of the single analog signal is generated to generate a combined digital signal (block 212). De-spread the digital version to generate a digital copy of each data packet communication signal (block 214).

In one aspect, the received signal is demodulated to the base frequency (block 204a) before generating each sampled and held analog signal. Alternatively, demodulate the received signal to an intermediate frequency (IF) before generating each sampled and held analog signal (block 204b). As another alternative embodiment, the received signal is not demodulated from the RF carrier frequency before generating the sampled and held analog signal (block 204c).

In the example shown in FIG. 3, the base stations 310a, 310b, and 310c may be giant base stations for the giant cells 302a, 302b, and 302c, respectively. The base station 310x may be a micro base station for the micro cell 302x communicating with the terminal 320x. The base station 310y may be an ultra-micro base station for the ultra-micro cell 302y that communicates with the terminal 320y. Although not shown in Figure 3 for simplicity, the megacells may overlap at the edges. Micro and ultra-micro cells may be located within a macro cell (as shown in FIG. 3) or may overlap with a macro cell and/or other cells.

The wireless network 300 may also include a relay station, for example, a relay station 310z that communicates with the terminal 320z. A repeater station is a station that receives the transmission of data and/or other information from an upstream station and sends the transmission of the data and/or other information to a downstream station. The upstream station can be a base station, another relay station or a terminal. The downstream station can be a terminal, another relay station or a base station. The repeater can also be a terminal that relays transmissions to other terminals. The repeater can transmit and/or receive low-reuse preconditions. For example, a repeater station can transmit a low reuse preamble in a similar manner to a micro base station, and can receive a low reuse preamble in a similar manner to a terminal.

The network controller 330 can be coupled to a group of base stations and can provide coordination and control for these base stations. The network controller 330 can be a single network entity or a collection of network entities. The network controller 330 can communicate with the base station 310 via a backhaul. The backhaul network communication 334 can facilitate the point-to-point communication between the base stations 310a to 310c using such a distributed architecture. The base stations 310a to 310c may also directly or indirectly communicate with each other via wireless or wired backhaul, for example.

The wireless network 300 may be a homogeneous network including only giant base stations (not shown in FIG. 3). The wireless network 300 may also be a heterogeneous network including different types of base stations (for example, giant base stations, micro base stations, indoor base stations, repeaters, etc.). These different types of base stations may have different transmission power levels, different coverage areas, and different effects on interference in the wireless network 300. For example, a mega base station may have a high transmission power level (for example, 20 watts), and a micro and ultra-micro base station may have a low transmission power level (for example, 3 watts). The techniques described in this article can be applied to homogeneous networks as well as heterogeneous networks.

The terminals 320 can be distributed throughout the wireless network 300, and each terminal can be fixed or mobile. Terminals can also be called access terminals (AT), mobile stations (MS), user equipment (UE), subscriber units, stations, etc. The terminal can be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless area loop (WLL) station, etc. The terminal can communicate with the base station via the downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the terminal, and the uplink (or reverse link) refers to the communication link from the terminal to the base station.

The terminal may be able to communicate with giant base stations, micro base stations, ultra-micro base stations, and/or other types of base stations. In FIG. 3, the solid line with double arrows indicates the desired transmission between the terminal and the servo base station, which is the base station designated to serve the terminal on the downlink and/or uplink. The dotted line with double arrows indicates the interference transmission between the terminal and the base station. The interfering base station is a base station that causes interference to the terminal on the downlink and/or observes the interference from the terminal on the uplink.

The wireless network 300 can support synchronous or asynchronous operation. For synchronous operation, base stations can have the same frame timing, and transmissions from different base stations can be aligned in time. For asynchronous operation, base stations may have different frame timings, and transmissions from different base stations cannot be aligned in time. For micro and ultra-micro base stations, asynchronous operation may be more common. Micro and ultra-micro base stations can be deployed indoors and may not be able to access synchronization sources such as the Global Positioning System (GPS).

In one aspect, in order to improve the system capacity, the coverage areas 302a, 302b, or 302c corresponding to the respective base stations 310a to 310c may be divided into multiple smaller areas (for example, areas 304a, 304b, and 304c). Each of the smaller areas 304a, 304b, and 304c can be served by a respective base transceiver subsystem (BTS, not shown). As used herein and generally in the art, the term "sector" can refer to a BTS and/or its coverage area depending on the context in which the term is used. In an example, the sectors 304a, 304b, and 304c in the cells 302a, 302b, and 302c can be formed by antenna groups (not shown) at the base station 310, where each antenna group is responsible for the The terminal 320 in a part of 302c communicates. For example, the base station 310 of the serving cell 302a may have a first antenna group corresponding to the sector 304a, a second antenna group corresponding to the sector 304b, and a third antenna group corresponding to the sector 304c. Antenna group. However, it should be understood that the various aspects disclosed herein can be used in systems with sectorized and/or unsectorized cells. In addition, it should be understood that all suitable wireless communication networks with any number of sectorized and/or unsectorized cells are intended to fall within the scope of the patent application appended here. For the sake of simplicity, the term "base station" used herein can refer to both the station serving the sector and the station serving the cell. It should be understood that, as used herein, downlink sectors are adjacent sectors in the case of disjoint links. Although the following description is generally related to a system in which each terminal communicates with one servo access point for simplicity, it should be understood that the terminal can communicate with any number of servo access points.

Referring to FIG. 4, a multiple access wireless communication system according to one aspect is illustrated. The access point (AP) 400 includes multiple antenna groups, including one antenna group 404 and 406, another antenna group including 408 and 410, and additional antenna groups including 412 and 414. In Figure 4, only two antennas are shown for each antenna group, however, more or fewer antennas can be utilized for each antenna group. The access terminal (AT) 416 communicates with antennas 412 and 414. The antennas 412 and 414 transmit information to the access terminal 416 on the forward link 420, and receive information from the access terminal on the reverse link 418. Information of machine 416. The access terminal 422 communicates with antennas 406 and 408. The antennas 406 and 408 transmit information to the access terminal 422 on the forward link 426, and receive information from the access terminal 422 on the reverse link 424. News. In an FDD system, the communication links 418, 420, 424, and 426 may use different frequencies for communication. For example, forward link 420 may use a different frequency than the frequency used by reverse link 418.

Each antenna group and/or area designed for communication is usually referred to as a sector of an access point. In this aspect, the antenna groups are each designed to communicate to the access terminal in a sector of the area covered by the access point 400.

In the communication on the forward links 420 and 426, the transmission antenna of the access point 400 uses beamforming to improve the signal-to-noise ratio for the forward links of the different access terminals 416 and 422. In addition, the use of beamforming to transmit to the access points of the access terminals randomly scattered in the coverage area causes less access to the access terminals in adjacent cells than the access points transmitted to all the access terminals via a single antenna. Interference.

An access point can be a fixed station used to communicate with a terminal, and can also be called an access point, node B, or some other terminology. The access terminal can also be referred to as an access terminal, user equipment (UE), wireless communication device, terminal, access terminal, or some other terminology.

5 shows a block diagram of the design of the communication system 500 between the base station 502 and the terminal 504. The base station 502 may be one of the base stations in FIG. 1, and the terminal 504 may be the terminal in FIG. One of them. The base station 502 can be equipped with TX antennas 534a to 534t, and the terminal 504 can be equipped with RX antennas 552a to 552r.<img file="TW201014237A_D0001.tif" />。

At the base station 502, the transmission processor 520 can receive the traffic data from the data source 512 and the information from the controller/processor 540. The transmission processor 520 can process (for example, encoding, interleaving, and modulation) communication data and messages, and provide data symbols and control symbols, respectively. The transmission processor 520 can also generate pilot symbols and data symbols for low reuse preambles and pilot symbols for other pilots and/or reference signals. The transmission (TX) multiple input multiple output (MIMO) processor 530 can perform spatial processing (for example, precoding) on data symbols, control symbols, and/or pilot symbols (if applicable), and can provide T output symbol streams Up to T modulators (MOD) 532a to 532t. Each modulator 532 can process a separate output symbol stream (for example, for OFDM, SC-FDM, etc.) to obtain an output sample stream. Each modulator 532 may further process (eg, convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The T downlink signals from the modulators 532a to 532t can be transmitted via the T antennas 534a to 534t, respectively.

At the terminal 504, the antennas 552a to 552r can receive downlink signals from the base station 502 and can provide the received signals to the demodulators (DEMODs) 554a to 554r, respectively. Each demodulator 554 can adjust (e.g., filter, amplify, down-convert, and digitize) a respective received signal to obtain input samples. Each demodulator 554 may further process the input samples (for example, for OFDM, SC-FDM, etc.) to obtain received symbols. The MIMO detector 556 can obtain received symbols from all R demodulators 554a to 554r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. The receiving processor 558 can process (for example, demodulate, deinterleave, and decode) the detected symbols, provide the decoded communication data for the terminal 504 to the data storage 560, and provide the decoded information To the controller/processor 580. The low reuse precondition (LRP) processor 584 can detect the low reuse precondition from the base station, and provides the information of the detected base station or cell to the controller/processor 580.

On the uplink, at the terminal 504, the transmission processor 564 can receive and process traffic data from the data source 562 and messages from the controller/processor 580. The symbols from the transmission processor 564 can be precoded by the TX MIMO processor 568 (if applicable), further processed by the modulators 554a to 554r, and transmitted to the base station 502. At the base station 502, the uplink signal from the terminal 504 can be received by the antenna 534, processed by the demodulator 532, detected by the MIMO detector 536 (if applicable), and further processed by the received data processor 538 To obtain the decoded packets and messages transmitted by the terminal 504 for providing to the data storage 539.

The controller/processors 540 and 580 can guide the operations at the base station 502 and the terminal 504, respectively. The processor 540 and/or other processors and modules at the base station 502 can perform or introduce the processing of the technology described in this document. The processor 584 and/or other processors and modules at the terminal 504 can execute or refer to the processing of the technology described herein. The memories 542 and 582 can store data and program codes for the base station 502 and the terminal 504, respectively. The scheduler 544 can schedule the terminal for data transmission on the downlink and/or uplink and can provide resource grants for the scheduled terminal.

To this end, FIG. 6 is a block diagram of a receiver 600 using two receiving antennas 602a, 602b according to one aspect. Although two antennas are depicted for clarity, it should be understood that with the benefits of the present disclosure, the method can be extended to support more than two antennas. The radio frequency (RF) receivers 604a and 604b operate at the carrier frequency received by the antennas 602a and 602b<i>f</i>_RFAmplified nearby and band-pass filtered. The respective mixers 606a, 606b use the local oscillator frequency<i>f</i>_LOCarrier frequency to be used for down conversion<i>f</i>_RFSet to the base frequency. The harmonics of each antenna branch 608a, 608b are removed by respective low-pass filters (LPF) 610a, 610b so as to<img file="TW201014237A_D0002.tif" />Generate a limited bandwidth signal<i>s</i>_<i>i</i><i>(t)</i>(i=1,2...M), where B is the signal bandwidth, and M is the number of antennas 602a and 602b. Separate sample and hold (S&amp;H) circuits 612a, 612b use orthogonal code signals with a bandwidth of M*B (for 2 antenna configurations, M=2)<i>C</i>_<i>1</i><i>(i)</i>、<i>C</i>_<i>2</i><i>(i)</i>Generated for spreading at 614a and 614b<i>S</i>□_<i>1</i><i>(kT</i>_<i>S</i><i>)</i>、<i>S</i>□_<i>2</i><i>(kT</i>_<i>S</i><i>)</i>, Resulting in a discrete analog signal that is added together at 616<i>S</i>_<i>1</i><i>(iT</i>_<i>C</i><i>)</i>、<i>S</i>_<i>1</i><i>(iT</i>_<i>C</i><i>)</i>. Express the spreading factor as<img file="TW201014237A_D0003.tif" />。

This combined signal is low-pass filtered (LPF) at 618 and converted to a digital format by a single analog-to-digital converter (ADC) 620. The output 622 from the ADC 620 is fed through the closed loop feedback of the automatic gain control (AGC) 624 to adjust the amplifier 626 at the input of the ADC 620 to obtain the full resolution capability of the ADC 620.

The digitized signal at 622 is fed to a set of correlators 628a, 628b (for two (2) antennas, M=2), and these correlators 628a, 628b are digitally combined with those used for spread spectrum operation. Same code<i>C</i>_<i>1</i><i>(i)</i>、<i>C</i>_<i>2</i><i>(i)</i>Set the correlation and perform the de-spreading operation, which are drawn at 630a and 630b respectively. The digitized baseband signal obtained by digital integration at 632a and 632b respectively is used to determine the digital form using the well-known technique in this technology<i>S</i>_<i>1</i><i>(k)</i>、<i>S</i>_<i>2</i><i>(k)</i>The information originally transmitted. Because multiplexing occurs at the base frequency, this scheme is called Base Frequency Division Code Multiplexing (BB-CDM).

In FIG. 7, the operation of the spreading and despreading circuit 700 is further emphasized in the two (2) antenna configuration for zero intermediate frequency (ZIF). As depicted in 706a and 706b respectively, the signals from antenna 1 704a and antenna 2 704b are respectively measured at the sampling frequency fs=1/Ts=2B through S&amp;H devices (not shown)<i>s</i>_<i>1</i><i>(t)</i>702a and signal<i>s</i>_<i>2</i><i>(t)</i>702b takes a sample. The resulting rectangular waveforms 706a, 706b of each branch and their associated spreading code C₁, C₂Multiply to produce spread spectrum signal<i>s</i>_<i>1</i><i>(nT</i>_<i>c</i><i>)</i>、<i>s</i>_<i>2</i><i>(nT</i>_<i>c</i><i>)</i>. For the case of two (2) antennas 704a, 704b, Ts/Tc=2, and for M antennas usually<i>Ts</i>/<i>Tc</i>=<i>M</i>. Spread spectrum signal of antenna 1 704a and antenna 2 704b<i>s</i>_<i>1</i><i>(n</i><i>T</i>_<i>c</i><i>)</i>、<i>s</i>_<i>2</i><i>(nT</i>_<i>c</i><i>)</i>They are added at 708 and digitized via a single ADC 710 respectively. As depicted at 712, the output of ADC 710 contains the nominal sample value superimposed by the quantization noise. The quantized signal 712 is fed to a set of digital correlators 714a, 714b, and these digital correlators 714a, 714b use code sequences for de-spreading<i>c</i>_<i>1</i><i>(n)</i>,<i>c</i>_<i>2</i><i>(n)</i>A digital copy to perform the despreading operation. When the orthogonality of the code sequence is given, the information belonging to each signal can be completely retrieved. In addition, assuming that the quantization errors observed on the samples are not correlated, the quantization noise power can be reduced by a factor of M in the de-spreading operation.

In Figure 8, in another aspect, code division multiplexing can also be applied to several points along the receiving chain instead of at zero intermediate frequency (fundamental frequency). For this reason, the spreading and despreading circuit 800 using S&amp;H devices 802a, 802b is applied to the intermediate frequency (IF) just after the mixing stages 804a, 804b. This can have greater advantages. In fact, different signals can now also share analog IF and BB filters and amplification stages, in which the bandwidth can be adjusted according to the spreading factor. This aspect is called IF multiplexing.

In this case, the S&amp;H circuit is moved from the base frequency (BB) to the intermediate frequency (IF), and the spreading operations depicted at 806a, 806b are adjusted accordingly. In detail, two or more antennas 808a, 808b receive the data packet communication signal filtered by the carrier frequency at the respective radio frequency (RF) front ends 810a, 810b. As depicted at 812, by combining multiple antenna signals at IF, it is possible to share a single IF to BB down-conversion chain 814 of BW=2*B (usually BW=M*B), resulting in an analog filter and analog Saving of both amplifier/attenuator and digital circuit. Specifically, it is a single IF surface acoustic wave filter 816, a single amplifier stage 818, a single ADC 820, a single numerically controlled oscillator (NCO) 822 and a single Digital Low Pass Filter (LPF) 824. In other aspects, different combinations of the aforementioned components and other components not mentioned herein can be shared by multiple antennas 808a, 808b.

Finally, the RF multiplexing scheme can be implemented by moving S&amp;H devices from IF to RF in a digital RF implementation that utilizes a high sampling rate. FIG. 9 shows an exemplary architecture of the RF-CDM multiplexing circuit 900. For this configuration, just after the low-noise amplification (LNA) stage and band-pass filter (BPF) filter, the respective S&amp;H circuits 902a, 902b compare the signal at RF.<i>s</i>_<i>１</i><i>(t)</i>and<i>s</i>_<i>2</i><i>(t)</i>The sampling is performed collectively as depicted by the RF front ends 904a, 904b fed from the respective RF antennas 906a, 906b. By spreading (depicted at 908a, 908b) and combining (depicted at 910), the signal is fed to a single RF-to-BB down-conversion chain 912, which uses a single mixer 914 together with the reuse factor already presented for IF-CDM implementation. Specifically, it is a single IF surface acoustic wave filter 916, a single ADC 920, a single numerically controlled oscillator (NCO) 922, and a single digital low-pass filter before diverging again to the digital correlators 926a, 926b that perform the despreading operation (LPF) 924. This aspect can potentially provide a greater cost reduction by reducing the number of analog mixers along with filters and amplifiers, although it may translate into more stringent requirements for ADCs.

Although the code division multiplexing (CDM) has been described in this article as an exemplary aspect, the multiplexing scheme can be extended to any form of orthogonal transformation, whether in time or frequency. For example, the aspect presented in this article is very suitable for LTE 4G systems, in which the supported bandwidth is adjusted to a factor of 2 for 5MHz, 10MHz and 20MHz. The proposed CDM-MIMO method can be used to demodulate a 10MHz system with 2 Rx antennas. This CDM-MIMO method reuses the available 20MHz system analog components.

Therefore, frequency division multiplexing (FDM) can be used instead of code division multiplexing (CDM) to provide orthogonality for combining signals received on different antennas for simultaneous sampling and processing. For example, an alternative method based on FDM can be used to multiplex multiple signals impinging on several antennas. FDM multiplexing can occur at the base frequency (BB), intermediate frequency (IF) or radio frequency (RF) by using multiple frequency synthesizers and mixers similar to the CDM method, each frequency synthesizer and mixer It is for each receiving antenna chain.

As another alternative embodiment, time division multiplexing (TDM) may be used instead of CDM to provide orthogonality for combining signals received on different antennas for simultaneous sampling and processing. In one aspect, a TDM-based method can be used to multiplex multiple signals impacted on several antennas. TDM multiplexing can occur at BB, IF, or RF similar to the CDM method. The TDM method uses a buffer of sampled data in the analog domain before multiplexing.

In Figure 10, the chart 1000 is the spread spectrum curve 1004 after Walsh spreading for the z1 signal and its fast Fourier transform (FFT) curve 1006, and the chart 1002 is the Walsh spreading curve for the z2 signal after The spread spectrum curve 1008 and its FFT curve 1010. As shown, the spectrum of the signal has not moved, but only increased and weighted the observation window size by FFT (WH). In FIG. 11, a graph 1100 depicts the orthogonality in the frequency domain of the demodulation symbol 1102 for one of the antennas.

In FIG. 12, the chart 1200 is the Walsh spread curve 1204 and its fast Fourier transform (FFT) curve 1206 after Walsh spread for the z1 signal, and the chart 1202 is the Walsh spread for the z2 signal with an interference signal. The spread spectrum curve 1208 and its FFT curve 1210 after frequency. As shown, the jammer did not move and no leakage was observed. In FIG. 13, a graph 1300 depicts the orthogonality in the frequency domain of the demodulation symbol 1302 for one of the antennas. The star diagram is depicted as more disturbing due to the filter decimation effect in Matlab used to perform the simulation.

Referring to Figure 14, a system 1400 for receiving wireless communications at a plurality of receiving antennas is illustrated. For example, the system 1400 may reside at least partially in a base station. It should be understood that the system 1400 is represented as including functional blocks, which can be functional blocks representing functions implemented by a computing platform, a processor, software, or a combination thereof (for example, firmware). System 1400 includes a logical grouping 1402 of electrical components that can act in conjunction. For example, the logical group 1402 may include a data packet communication signal for receiving at each of a plurality of antennas modulated on a radio frequency (RF) carrier frequency and possibly (but not necessarily) for spatial diversity encodingOf a powerComponent 1404. In addition, the logical group 1402 may include an electrical component 1406 for processing the received data packet communication signal at the corresponding plurality of receive chains for each of the plurality of antennas to generate a plurality of analog signals. In addition, the logical group 1402 may include an electrical component 1408 for generating a sampled and held analog signal for each of the plurality of analog signals, respectively. The logical group 1402 may include an electrical component 1410 for spreading each sampled and held analog signal by a unique spreading code. In addition, the logical group 1402 can include an electrical component 1412 for combining each of the spread-spectrum sampled and held analog signals to generate a single analog signal. In addition, the logic group 1402 may include an electrical component 1414 for generating a digital version of the single analog signal to generate a combined digital signal. The logical group 1402 may include an electrical component 1416 for spreading each sampled and held analog signal by a unique spreading code. In addition, the system 1400 may include a memory 1420 that stores instructions for executing functions associated with the electrical components 1404 to 1416. Although shown as being external to the memory 1420, it should be understood that one or more of the electrical components 1404-1416 may be present in the memory 1420.

Referring to FIG. 15, a device 1502 for receiving wireless communications at a plurality of receiving antennas is provided. A means 1504 for receiving a data packet communication signal modulated on a radio frequency (RF) carrier frequency and possibly (but not necessarily) for spatial diversity coding is provided at each of a plurality of antennas. A means 1506 for processing the received data packet communication signal at the corresponding plurality of receiving chains for each of the plurality of antennas is provided to generate a plurality of analog signals. A means 1508 for generating a sampled and held analog signal for each of the plurality of analog signals is provided. A means 1510 for spreading each sampled and held analog signal by a unique spreading code is provided. A means 1512 for combining the sampled and held analog signals of each spread spectrum to generate a single analog signal is provided. A means 1514 for generating a digital version of the single analog signal to generate a combined digital signal is provided. A means 1516 for de-spreading the digital version to generate a digital copy of each data packet communication signal is provided.

Those familiar with this technology will understand that any of a variety of different techniques and techniques can be used to represent information and signals. For example, voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof can be used to represent data, instructions, commands, information, signals, bits, symbols, and codes that may be referenced throughout the above description. piece.

Those familiar with the technology will further understand that the various illustrative logic blocks, modules, circuits, and algorithm steps described in the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in accordance with their functionality. Whether this functionality is implemented as hardware or software depends on the specific application and design constraints imposed on the entire system. For each specific application, those familiar with the technology can implement the described functionality in various ways, but these implementation decisions should not be interpreted as causing a departure from the scope of this disclosure.

As used in this application, the terms "component", "module", "system" and the like are intended to refer to computer-related entities, which are either hardware, a combination of hardware and software, software, or execution Software in. For example, the component may be (but is not limited to) a processing program, processor, object code, executable code, thread, program, and/or computer executed on the processor. By way of explanation, both the application running on the server and the server can be components. One or more components can reside in processing programs and/or threads, and the components can be located on one computer and/or distributed between two or more computers.

The word "exemplary" is used herein to mean serving as an example, example, or illustration. It is not necessary to interpret any aspect or design described as "exemplary" herein as being better or superior to other aspects or designs.

Various aspects will be presented based on a system that can include many components, modules, and the like. It should be understood and understood that various systems may include additional components, modules, etc., and/or may not include all of the components, modules, etc. discussed in conjunction with the figures. A combination of these methods can also be used. The various aspects disclosed herein can be implemented on power devices, including devices that utilize touch screen display technology and/or mouse and keyboard-type interfaces. Examples of such devices include computers (desktop and mobile), smart phones, personal digital assistants (PDAs), and other electronic devices, both wired and wireless.

In addition, general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable gate arrays designed to perform the functions described in this article can be used Logic logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof implement or execute various illustrative logic blocks, modules, and circuits described in conjunction with the embodiments disclosed herein. The general-purpose processor may be a microprocessor, but in alternative embodiments, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with DSP cores, or any other such configuration.

In addition, by using standard programming and/or engineering techniques to generate software, firmware, hardware, or any combination thereof to control a computer to implement the disclosed aspects, one or more versions can be implemented as methods and devices Or products. As used herein, the term "product" (or "computer program product") is intended to cover a computer program that can be accessed from any computer-readable device, carrier, or medium. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips, ...), optical discs (e.g., compact discs (CD), digital universal optical discs) (DVD),...), smart cards and flash memory devices (for example, cards, sticks). In addition, it should be understood that carrier waves can be used to carry computer-readable electronic data such as those used to transmit and receive electronic mail or to access networks such as the Internet or a local area network (LAN). Of course, those familiar with the technology will realize that many modifications can be made to this configuration without departing from the scope of the disclosed aspect.

The steps of the method or algorithm described in combination with the embodiments disclosed herein can be directly embodied in hardware, in a software module executed by a processor, or a combination of the two. The software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, scratchpad, hard disk, removable disc, CD-ROM, or known in this technology In any other form of storage media. The exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. In an alternative embodiment, the storage medium may be integrated into the processor. The processor and storage medium may reside in the ASIC. The ASIC can reside in the user terminal. In an alternative embodiment, the processor and the storage medium may reside as discrete components in the user terminal.

The foregoing description of the disclosed embodiments is provided to enable anyone familiar with the art to make or use the present disclosure. Various modifications of these embodiments will be obvious to those familiar with the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments shown in this article, but should conform to the broadest scope consistent with the principles and novel features disclosed in this article.

In view of the foregoing exemplary system, several flowcharts have been referred to to describe methods that can be implemented in accordance with the disclosed subject matter. Although the method is shown and described as a series of blocks for the purpose of simple explanation, it should be understood and understood that the claimed subject matter is not limited by the order of the blocks, because some blocks may be different from those depicted in this article And the described order occurs sequentially and/or simultaneously with other blocks. In addition, all the blocks described may not be required to implement the methods described herein. In addition, it should be further understood that the methods disclosed herein can be stored on the article to facilitate the delivery and transfer of these methods to the computer. As used herein, the term "article" is intended to encompass a computer program that can be accessed from any computer-readable device, carrier, or medium.

It should be understood that any patent, publication or other disclosure material that is said to be incorporated herein by reference is only in the case that the incorporated material does not correspond to the existing definition, description or other disclosure material set forth in this disclosure The extent of the conflict is fully or partially incorporated in this article. Therefore, and to the extent necessary, any conflicting material incorporated in this article by reference is replaced by the disclosure as clearly stated in this article. Any material or part thereof that is said to be incorporated herein by reference but conflicts with the existing definitions, narratives, or other disclosure materials set forth herein will only be between the incorporated materials and the existing disclosure materials. Incorporate to the extent of conflict.

<p>100. . . Communication Systems</p><p>102. . . Transmission entity</p><p>104a. . . Transmission (Tx) antenna</p><p>104b. . . Transmission (Tx) antenna</p><p>106. . . Air link</p><p>108a. . . Data packet communication signal</p><p>108b. . . Data packet communication signal</p><p>110. . . Receiving entity</p><p>112a. . . Receiving (Rx) antenna</p><p>112b. . . Receiving (Rx) antenna</p><p>114a. . . Receiving chain</p><p>116a. . . RF front end</p><p>118a. . . Sample and hold circuit</p><p>120a. . . Radio frequency to intermediate frequency (RF-IF) demodulator</p><p>122a. . . Sample and hold circuit</p><p>124a. . . Radio frequency to baseband (RF-BB) demodulator</p><p>126a. . . Sample and hold circuit</p><p>128a. . . Unique Spread Spectrum Code Mixer</p><p>128b. . . Unique Spread Spectrum Code Mixer</p><p>130. . . Summator</p><p>132. . . Analog to Digital Converter (ADC)</p><p>134a. . . Digital Correlator</p><p>134b. . . Digital correlator</p><p>300. . . Wireless network</p><p>302a. . . Mega cell/coverage area</p><p>302b. . . Mega cell/coverage area</p><p>302c. . . Mega cell/coverage area</p><p>302x. . . Micro cell</p><p>302y. . . Ultra-micro cell</p><p>304a. . . Area/sector</p><p>304b. . . Area/sector</p><p>304c. . . Area/sector</p><p>310. . . Base station</p><p>310a. . . Base station</p><p>310b. . . Base station</p><p>310c. . . Base station</p><p>310x. . . Base station</p><p>310y. . . Base station</p><p>310z. . . Repeater</p><p>320. . . Terminal</p><p>320x. . . Terminal</p><p>320y. . . Terminal</p><p>320z. . . Terminal</p><p>330. . . Network controller</p><p>334. . . Backhaul network communication</p><p>400. . . Access point (AP)</p><p>404. . . antenna</p><p>406. . . antenna</p><p>408. . . antenna</p><p>410. . . antenna</p><p>412. . . antenna</p><p>414. . . antenna</p><p>416. . . Access Terminal (AT)</p><p>418. . . Reverse link</p><p>420. . . Forward link</p><p>422. . . Access terminal</p><p>424. . . Reverse link</p><p>426. . . Forward link</p><p>500. . . Communication Systems</p><p>502. . . Base station</p><p>504. . . Terminal</p><p>512. . . Data source</p><p>520. . . Transport processor</p><p>530. . . Transmission (TX) Multiple Input Multiple Output (MIMO) processor</p><p>532a. . . Modulator (MOD)</p><p>532t. . . Modulator (MOD)</p><p>534a. . . TX antenna</p><p>534t. . . TX antenna</p><p>536. . . MIMO detector</p><p>538. . . Receive data processor</p><p>539. . . Data storage</p><p>540. . . Controller/Processor</p><p>542. . . Memory</p><p>544. . . Scheduler</p><p>552a. . . RX antenna</p><p>552r. . . RX antenna</p><p>554a. . . Demodulator (DEMOD)</p><p>554r. . . Demodulator (DEMOD)</p><p>556. . . MIMO detector</p><p>558. . . Receiving processor</p><p>560. . . Data storage</p><p>562. . . Data source</p><p>564. . . Transport processor</p><p>568. . . TX MIMO processor</p><p>580. . . Controller/Processor</p><p>582. . . Memory</p><p>584. . . Low reuse pre-term (LRP) processor</p><p>600. . . receiver</p><p>604a. . . Radio Frequency (RF) Receiver</p><p>604b. . . Radio Frequency (RF) Receiver</p><p>606a. . . Mixer</p><p>606b. . . Mixer</p><p>608a. . . Antenna branch</p><p>608b. . . Antenna branch</p><p>610a. . . Low pass filter (LPF)</p><p>610b. . . Low pass filter (LPF)</p><p>612a. . . Sample and hold (S&amp;H) circuit</p><p>612b. . . Sample and hold (S&amp;H) circuit</p><p>620. . . Analog to Digital Converter (ADC)</p><p>622. . . Output</p><p>624. . . Automatic gain control (AGC)</p><p>626. . . Amplifier</p><p>628a. . . Correlator</p><p>628b. . . Correlator</p><p>700. . . Spread spectrum and despread spectrum circuit</p><p>702a. . . Signal<i>s</i>_<i>1</i>(<i>t</i>)</p><p>702b. . . Signal<i>s</i>_<i>2</i>(<i>t</i>)</p><p>704a. . . antenna</p><p>704b. . . antenna</p><p>706a. . . Obtained rectangular waveform</p><p>706b. . . Obtained rectangular waveform</p><p>710. . . Single ADC</p><p>712. . . Quantized signal</p><p>714a. . . Digital Correlator</p><p>714b. . . Digital Correlator</p><p>800. . . Spread spectrum and despread spectrum circuit</p><p>802a. . . S&amp;H device</p><p>802b. . . S&amp;H device</p><p>804a. . . Mixing stage</p><p>804b. . . Mixing stage</p><p>808a. . . antenna</p><p>808b. . . antenna</p><p>810a. . . Radio Frequency (RF) Front End</p><p>810b. . . Radio Frequency (RF) Front End</p><p>814. . . Single IF to BB down conversion chain</p><p>816. . . Single IF surface acoustic wave filter</p><p>818. . . Single amplification stage</p><p>820. . . Single ADC</p><p>822. . . Single Numerically Controlled Oscillator (NCO)</p><p>824. . . Single Digital Low Pass Filter (LPF)</p><p>826a. . . Digital Correlator</p><p>826b. . . Digital correlator</p><p>900. . . RF-CDM multiplex circuit</p><p>902a. . . S&amp;H circuit</p><p>902b. . . S&amp;H circuit</p><p>904a. . . RF front end</p><p>904b. . . RF front end</p><p>906a. . . RF antenna</p><p>906b. . . RF antenna</p><p>912. . . Single RF to BB down conversion chain</p><p>914. . . Single mixer</p><p>916. . . Single IF surface acoustic wave filter</p><p>920. . . Single ADC</p><p>922. . . Single Numerically Controlled Oscillator (NCO)</p><p>924. . . Single Digital Low Pass Filter (LPF)</p><p>926a. . . Digital correlator</p><p>926b. . . Digital correlator</p><p>1000. . . chart</p><p>1002. . . chart</p><p>1004. . . Spreading curve after Walsh spreading for z1 signal</p><p>1006. . . Fast Fourier Transform (FFT) curve</p><p>1008. . . Spreading curve after Walsh spreading for z2 signal</p><p>1010. . . FFT curve</p><p>1100. . . chart</p><p>1102. . . Demodulation symbol</p><p>1200. . . chart</p><p>1202. . . chart</p><p>1204. . . Spreading curve after Walsh spreading for z1 signal</p><p>1206. . . Fast Fourier Transform (FFT) curve</p><p>1208. . . Spreading curve after Walsh spreading for z2 signal with an interference signal</p><p>1210. . . FFT curve</p><p>1300. . . chart</p><p>1302. . . Demodulation symbol</p><p>1400. . . System for receiving wireless communication at a plurality of receiving antennas</p><p>1402. . . Logical group</p><p>1404. . . Electrical components for receiving at each of a plurality of antennas a data packet communication signal modulated on a radio frequency (RF) carrier frequency and possibly (but not necessary) for spatial diversity coding</p><p>1406. . . An electrical component for processing the received data packet communication signal at the corresponding plurality of receiving chains for each of the plurality of antennas to generate a plurality of analog signals</p><p>1408. . . Electrical component for generating a sampled and held analog signal for each of the plurality of analog signals</p><p>1410. . . Electrical components used to spread each sampled and held analog signal by a unique spreading code</p><p>1412. . . Electrical component for combining each sampled and held analog signal with spread spectrum to produce a single analog signal</p><p>1414. . . Electrical component for generating a digital version of the single analog signal to generate a combined digital signal</p><p>1416. . . Electrical components used to spread each sampled and held analog signal by a unique spreading code</p><p>1420. . . Memory</p><p>1502. . . Device</p><p>1504. . . A component used to receive a data packet communication signal modulated on a radio frequency (RF) carrier frequency and possibly (but not necessary) for spatial diversity coding at each of a plurality of antennas</p><p>1506. . . Means for processing the received data packet communication signal at the corresponding plurality of receiving chains for each of the plurality of antennas to generate a plurality of analog signals</p><p>1508. . . A means for generating a sampled and held analog signal for each of the plurality of analog signals</p><p>1510. . . A component used to spread each sampled and held analog signal by a unique spreading code</p><p>1512. . . A component used to combine the sampled and held analog signals of each spread spectrum to produce a single analog signal</p><p>1514. . . A component for generating a digital version of the single analog signal to generate a combined digital signal</p><p>1516. . . A component for de-spreading the digital version to generate a digital copy of each data packet communication signal</p>

Figure 1 depicts a block diagram of a wireless communication system in which a data packet communication signal is received by multiple antennas of a receiving entity;

Figure 2 depicts a flow chart of a method or sequence of operations for receiving wireless communications at a plurality of receiving antennas;

Figure 3 depicts a block diagram of a base station that serves and interferes with many terminals;

Figure 4 depicts a block diagram of a multiple access wireless communication system;

Figure 5 depicts a block diagram of the communication system between the base station and the terminal;

Figure 6 depicts a block diagram of a receiving entity with multiple receiving chains, which are orthogonally spread in the base frequency and combined for digital processing and subsequent de-spreading;

Figure 7 depicts a block diagram with a waveform illustrating code division multiplexing in order to combine multiple antenna receive chains after the stage;

FIG. 8 depicts a block diagram of a receiving entity with multiple receiving chains, which are orthogonally spread in the intermediate frequency and combined for digital processing and subsequent de-spreading;

9 depicts a block diagram of a receiving entity with multiple receiving chains, which are orthogonally spread in the radio frequency and combined for digital processing and subsequent de-spreading;

Fig. 10 depicts the frequency spread curve and its fast Fourier transform (FFT) curve after Walsh spread for the z1 signal, and the frequency spread curve and its FFT curve after Walsh spread for the z2 signal;

FIG. 11 depicts a graph of orthogonality in the frequency domain of demodulated symbols for the signal of FIG. 10;

Figure 12 depicts a graph of the spread spectrum after Walsh spreading of the z1 signal and its FFT graph, and a graph of the spread spectrum after Walsh spreading of the z2 signal with an interfering signal and its FFT graph ;

FIG. 13 depicts a graph of orthogonality in the frequency domain of demodulated symbols for the signal of FIG. 12;

Figure 14 depicts a block diagram of a system containing a logical grouping of electronic components for receiving wireless communications at a plurality of receiving antennas; and

Figure 15 depicts a block diagram of an apparatus having means for receiving wireless communications at a plurality of receiving antennas.