HK1118973B

HK1118973B - Method and system for ofdm based mimo system with enhanced diversity

Info

Publication number: HK1118973B
Application number: HK08110719.1A
Authority: HK
Inventors: 阿玛德雷兹．罗弗戈兰
Original assignee: 美国博通公司
Priority date: 2006-09-29
Filing date: 2008-09-26
Publication date: 2011-12-16

Description

Method and system for processing signals in a communication network

Technical Field

The present invention relates to wireless communication systems, and more particularly, to a method and system for an Orthogonal Frequency Division Multiplexing (OFDM) based Multiple Input Multiple Output (MIMO) system with enhanced diversity.

Background

In most wireless communication systems today, nodes in the network may be configured to operate based on a single transmit and a single receive antenna. However, for many current wireless systems, the use of multiple transmit and/or receive antennas improves overall system performance. These multiple antenna configurations, also referred to as smart antenna techniques, may be used to reduce the negative effects of multipath and/or signal interference in signal reception. Existing systems that are currently being deployed, such as CDMA-based systems, TDMA-based systems, WLAN systems, and OFDM-based systems such as ieee802.11a/g/n, benefit from multiple transmit and/or receive antenna-based configurations. It is anticipated that smart antenna technology will be increasingly used in conjunction with base station architectures and mobile subscriber units in cellular systems to meet the increasing capacity demands placed on those systems. These requirements stem in part from the transition from current voice-based services to next generation wireless multimedia services that provide voice, video, and data communications.

The use of multiple transmit and/or receive antennas is designed to introduce diversity gain and array gain (arraygain) and to suppress interference generated during signal reception. Such diversity gain improves system performance by increasing received signal-to-noise ratio, providing greater robustness against signal interference, and/or allowing greater frequency reuse for higher capacity. Systems utilizing multiple transmit and multiple receive antennas may be referred to as multiple-input multiple-output (MIMO) systems. In certain MIMO systems, an attractive aspect of multi-antenna systems is that by utilizing these transmission configurations, the system capacity is significantly increased. For a fixed total transmission power, the capacity provided by a MIMO configuration is proportional to the increased signal-to-noise ratio (SNR).

In order to transfer the maximum energy and power between the transmit and receive antennas, the transmit and receive antennas must have the same spatial orientation, the same polarization direction, and the same axial ratio. When the antennas are not aligned or have the same polarization, the energy or power transfer between the two antennas is reduced. This reduction in power transmission will reduce overall system efficiency and performance. When both transmit and receive antennas are linearly polarized, physical misalignment of the antennas can result in polarization mismatch losses.

Multipath signals reach the mobile handset antenna by reflection of the direct signal by nearby objects. If the reflectors are oriented such that they are not in the same direction as the polarization of the incident wave, the reflected wave will experience a polarization phase shift. The final or total signal available to the receiver at one end of the communication link is the vector sum of the direct signal and all multipath signals. In many instances, there are multiple signals arriving at the receiving station with different polarization directions than the system antenna. When the receive antenna is rotated from vertical to horizontal, it intercepts or receives energy from the multiple signals.

In a polarization diversity system, dual linear polarized antennas may be used to receive the samples and track the polarization output that provides the strongest signal level. Each output may provide a total signal, which may be a combination of all incident signals. This combined signal is a function of the amplitude and phase of the signals, and the polarization mismatch.

In a radio system where the mobile user terminal has a limited number of antennas, transmit antenna diversity can be used to obtain diversity gain against rayleigh fading. Antenna hopping can utilize transmit antennas to obtain diversity gain. Using antenna hopping, cyclic or pseudo-random hopping may be used to convert spatial diversity into time diversity, which is used by suitable error correction codes and interleaving techniques, but due to error correction codes, interleaving requirements and/or possible bandwidth expansion may result in latency.

Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.

Disclosure of Invention

The present invention is directed to a method and/or system for an Orthogonal Frequency Division Multiplexing (OFDM) -based multiple-input multiple-output (MIMO) system, substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims.

According to an aspect of the present invention, there is provided a method of processing signals in a communication network, the method comprising:

in a Radio Frequency (RF) system including a plurality of antennas, selecting at least one group of antennas from the plurality of antennas; and

transmitting data through the selected at least one set of antennas, the at least one set of antennas including at least one polarized antenna that is orthogonally polarized with respect to an adjacent polarized antenna.

Preferably, the method further comprises placing the at least one polarized antenna at a certain distance from at least one other polarized antenna, the at least one other polarized antenna being coherently polarized with respect to the at least one polarized antenna.

Preferably, the method further comprises placing the at least one polarized antenna at a certain distance from at least one other polarized antenna, the at least one other polarized antenna being coherently polarized with respect to each of the adjacent polarized antennas.

Preferably, the method further comprises transmitting said data via said at least one polarized antenna that is orthogonally polarized with respect to an adjacent polarized antenna.

Preferably, the method further comprises receiving the data by the at least one polarized antenna that is orthogonally polarized with respect to an adjacent polarized antenna.

Preferably, the method further comprises switching between a plurality of said selected at least one group of antennas.

Preferably, the method further comprises selecting at least one antenna from the selected at least one group of antennas to transmit the data.

According to one aspect of the present invention, there is provided a machine readable storage, having stored thereon, a computer program having at least one code section for processing signals in a communication network, the at least one code section being executable by a machine for causing the machine to perform the steps of:

Preferably, said at least one code segment comprises code for placing said at least one polarized antenna at a certain distance from at least one other polarized antenna, said at least one other polarized antenna being coherently polarized with respect to said at least one polarized antenna.

Preferably, said at least one code segment comprises code for placing said at least one polarized antenna at a certain distance from at least one other polarized antenna, said at least one other polarized antenna being coherently polarized with respect to said adjacent polarized antenna.

Preferably, said at least one code segment comprises code for transmitting said data via said at least one polarized antenna which is orthogonally polarized with respect to an adjacent polarized antenna.

Preferably, said at least one code segment comprises code for receiving said data via said at least one polarized antenna orthogonally polarized with respect to an adjacent polarized antenna.

Preferably, said at least one code segment comprises code for switching between a plurality of said selected at least one set of antennas.

Preferably, the at least one code segment comprises code for selecting at least one antenna from the selected at least one group of antennas for transmitting the data.

According to an aspect of the present invention, there is provided a system for processing signals in a communication network, the system comprising:

at least one circuit in a Radio Frequency (RF) system for selecting at least one group of antennas from a plurality of antennas; and is

The at least one circuit transmits data through the selected at least one group of antennas, wherein the selected at least one group of antennas includes at least one polarized antenna that is orthogonally polarized with respect to an adjacent polarized antenna.

Preferably, said at least one polarized antenna is placed at a certain distance from at least one other polarized antenna, said at least one other polarized antenna being coherently polarized with respect to said at least one polarized antenna.

Preferably, said at least one polarized antenna is placed at a certain distance from at least one other polarized antenna, said at least one other polarized antenna being coherently polarized with respect to each of said adjacent polarized antennas.

Preferably, the at least one circuit transmits the data via the at least one polarized antenna that is orthogonally polarized with respect to an adjacent polarized antenna.

Preferably, the at least one circuit receives the data via the at least one polarized antenna that is orthogonally polarized with respect to an adjacent polarized antenna.

Preferably, the at least one circuit switches between a plurality of the selected at least one group of antennas.

Preferably, the at least one circuit selects at least one antenna from the selected at least one group of antennas to transmit the data.

Various advantages, objects, and novel features of the invention, as well as details of an illustrated embodiment thereof, will be more fully understood from the following description and drawings.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1A is a schematic block diagram of a Radio Frequency (RF) system having a wireless communication master and associated radios in accordance with embodiments of the present invention;

fig. 1B is a schematic illustration of antenna polarization in a wireless communication system according to an embodiment of the present invention;

FIG. 1C is a block diagram of an exemplary OFDM-based multiple-input multiple-output (MIMO) system in accordance with an embodiment of the present invention;

FIG. 2 is a block diagram of an exemplary Radio Frequency (RF) receiver according to an embodiment of the present invention;

fig. 3A is a schematic diagram of an exemplary antenna architecture of a multiple antenna Orthogonal Frequency Division (OFD) based system according to an embodiment of the present invention;

fig. 3B is a schematic diagram of another exemplary antenna architecture of a multiple antenna Orthogonal Frequency Division (OFD) based system according to an embodiment of the present invention;

fig. 4 is a schematic block diagram of a typical switching mechanism in an Orthogonal Frequency Division Multiplexing (OFDM) -based multiple-input multiple-output (MIMO) system according to an embodiment of the present invention.

Detailed Description

Embodiments of the present invention relate to a method and/or system for an Orthogonal Frequency Division Multiplexing (OFDM) -based multiple-input multiple-output (MIMO) system with enhanced diversity. The present invention includes selecting a set of antennas from a plurality of antennas of a Radio Frequency (RF) system. Data may be transmitted through the selected set of antennas. The selected set of antennas includes at least one polarized antenna that is orthogonally polarized with respect to adjacent polarized antennas. The plurality of polarized antennas may be placed at a certain distance from each other.

Fig. 1A is a schematic block diagram of a Radio Frequency (RF) system having a wireless communication master and associated radios in accordance with an embodiment of the present invention. Referring to fig. 1A, a Radio Frequency (RF) system 100 is shown including a wireless communication master device 10 and an associated RF subsystem 60.

Wireless communication master device 10 includes a processing module 50, a wireless interface 54, an input interface 58, and an output interface 56. Processing module 50 and memory 52 may be used to execute a plurality of instructions. For example, for a cellular telephone host device, the processing module 50 may be used to perform corresponding communication functions according to a particular cellular telephone standard.

The wireless interface 54 may be used to allow data to be received from the RF subsystem 60 and transmitted to the RF subsystem 60. The wireless interface 54 is used to provide data received from the RF subsystem 60 to the processing module 50 for further processing and/or routing to the output interface 56. The output interface 56 is for connection to an output device, such as a display, monitor or speaker, for displaying received data. The wireless interface 54 is used to provide data from the processing module 50 to the RF subsystem 60. The processing module 50 is operative to receive outbound signals from an input device such as a keyboard, keypad or microphone via the input interface 58 or to generate data itself. The processing module 50 is used to perform corresponding main functions on data received via the input interface 58 and/or to route data to the RF subsystem 60 via the wireless interface 54.

For a cellular telephone host, the RF subsystem 60 may be a built-in component. For a personal digital assistant host, a laptop host, and/or a personal computer host, the RF subsystem 60 may be a built-in or externally connected component. The RF subsystem 60 includes a main interface 62, a digital receiver processing module 64, and an analog-to-digital converter 66, a filtering/gain module 68, a down-conversion module 70, a low noise amplifier 72, a receiver filtering module 71, a transmitter/receiver (Tx/Rx) switching module 73, a local oscillation module 74, a memory 75, a digital transmit processing module 76, a digital-to-analog converter 78, a filtering/gain module 80, an up-conversion module 82, a power amplifier 84, a transmitter filtering module 85, and a plurality of antennas, namely an antenna 186 a, an antenna 286 b, and an antenna 386 c, operatively connected as shown. The antenna 286 b may be shared by the transmit and receive paths conditioned by the Tx/Rx switching module 73.

Antenna 186 a is polarized at a polarization angle of, for example, 0 degrees. Antenna 286 b is orthogonally polarized with respect to antenna 186 a, with a 90 degree polarization angle. Antenna 386 c is orthogonally polarized with respect to antenna 286 b and coherently polarized with respect to antenna 186 a, with a polarization angle of 0 degrees or 180 degrees. Multiple coherently polarized antennas, such as antenna 186 a and antenna 386 c, are placed at a particular distance d from each other. Multiple antennas, such as antenna 186 a, antenna 286 b, and antenna 386 c, may be configured to provide spatial and/or temporal isolation. Polarized antennas, such as antenna 186 a, antenna 286 b, and antenna 386 c, may achieve a reduction in space between the antennas and provide isolation.

The digital receiver processing module 64 and the digital transmitter processing module 76, in conjunction with operating instructions stored in the memory 75, may be used to perform digital receiver functions and digital transmitter functions, respectively. Digital receiver functions include, but are not limited to, demodulation, constellation demapping, decoding, and/or descrambling. Digital transmitter functions include, but are not limited to, scrambling, encoding, constellation mapping, and modulation. The digital receiver and transmitter processing modules 64 and 76 may each be implemented using a shared processing device, a single processing device, or multiple processing devices, such as microprocessors, microcontrollers, digital signal processors, microcomputers, central processing units, field programmable gate arrays, programmable logic devices, state machines, logic circuits, analog circuits, digital circuits, and/or any device that processes (analog and/or digital) signals in accordance with operational instructions.

The memory 75 may be a single memory device or a plurality of memory devices. For example, memory 75 may be read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, and/or any device that stores digital information. When digital receiver processing module 64 and digital transmitter processing module 76 perform one or more of its functions via a state machine, analog circuitry, digital circuitry, and/or logic circuitry, memory storing corresponding operational instructions may be embedded within the circuitry comprising the state machine, analog circuitry, digital circuitry, and/or logic circuitry. The memory 75 may be used to store, and the digital receiver processing module 64 and/or the digital transmitter processing module 76 may be used to execute, operational instructions corresponding to the at least some functions.

In operation, the RF subsystem 60 is operable to receive outbound (outbound) data from the wireless communication host device 10 via the host interface 62. The main interface 62 is used to route outbound data to the digital transmitter processing module 76. Digital transmitter processing module 76 may be used to process the outbound data according to a particular wireless communication standard or protocol, such as IEEE802.11a, IEEE802.11 b, ZigBee, and bluetooth, to generate data in a digital transmission format. The data in a digital transmission format may be a digital baseband signal or a digital low-IF signal, where the low-IF is located in a frequency range of, for example, one hundred kilohertz to several megahertz.

The digital-to-analog converter 78 is used to convert the digital transmission format signal from the digital domain to the analog domain. The filter/gain module 80 is used to filter and/or adjust the gain of the analog baseband signal before providing the signal to the up-conversion module 82. The up-conversion module 82 is used to directly convert the analog baseband signal or the low IF signal to an RF signal based on the transmitter local oscillation 83 provided by the local oscillation module 74. The power amplifier 84 is used to amplify the RF signal to generate an outbound RF signal that is filtered by the transmitter filtering module 85. The antenna 86a may be used to transmit the outbound RF signal to a destination device, such as a base station, an access point, and/or another wireless communication device.

The RF subsystem 60 may be used to receive inbound RF signals transmitted by base stations, access points, and other wireless communication devices via an antenna 86 a. The antenna 86a transmits the inbound RF signals to the receiver filtering module 71 through the Tx/Rx switching module 73, wherein the Rx filtering module 71 band-pass filters the inbound RF signals. The Rx filtering module 71 is used to transmit the filtered RF signal to a low noise amplifier 72, and the low noise amplifier 72 may amplify the inbound RF signal to generate an amplified inbound RF signal. The low noise amplifier 72 is used to pass the amplified inbound RF signal to the down conversion module 70, and the down conversion module 70 directly converts the amplified inbound RF signal to an inbound low IF signal or baseband signal based on receiver local oscillation provided by the local oscillation module 74. The down conversion module 70 is used to pass the inbound low IF signal or baseband signal to the filter/gain module 68. The filter/gain module 68 is used to filter and/or attenuate the inbound low-IF signal or the inbound baseband signal to generate a filtered inbound signal.

The analog-to-digital converter 66 is used to convert the filtered inbound signal from the analog domain to the digital domain to generate data in a digital receive format. The digital receiver processing module 64 is used to decode, descramble, demap and/or demodulate data in a digital reception format to retrieve inbound data. The host interface 62 communicates the retrieved inbound data to the wireless communication host device 10 via the wireless interface 54.

The local oscillation module 74 is used to adjust the output frequency of the received local oscillation signal. The local oscillation module 74 is configured to receive a frequency correction input to adjust the output local oscillation signal to generate a frequency corrected local oscillation signal output.

Fig. 1B is a schematic diagram of antenna polarization in a wireless communication system according to an embodiment of the present invention. Referring to fig. 1B, a polarized antenna 150 is shown. The energy radiated by polarized antenna 150 is a transverse electromagnetic wave that includes an electric field and a magnetic field. These fields are always orthogonal to each other and to the direction of propagation. The electric field E of an electromagnetic wave can be used to describe its polarization. The total electric field of the electromagnetic wave comprises two linear components orthogonal to each other. Each of these two components has a different amplitude and phase. At a fixed point along the propagation direction, the trajectory of the total electric field is elliptical, as a function of time. For example, at any instant, Ex is the electric field component in the x-direction and Ey is the electric field component in the y-direction. The total electric field E is the vector sum of Ex and Ey.

Elliptical polarization may include two cases, for example, circular polarization and linear polarization. A circularly polarized electromagnetic wave may comprise two linearly polarized electric field components that are orthogonal, of equal amplitude, and 90 degrees out of phase. In this case, the polarization ellipse of the electromagnetic wave is circular. The electromagnetic wave may be left-hand circularly polarized or right-hand circularly polarized depending on the rotation direction of the circularly polarized wave. The phase relationship between two 90 degree or-90 degree orthogonal components determines the direction of rotation. A linearly polarized electromagnetic wave includes a single electric field component, and the elliptical trajectory of polarization of the electromagnetic wave is a straight line.

Fig. 1C is a block diagram of an exemplary OFDM-based multiple-input multiple-output (MIMO) system in accordance with an embodiment of the present invention. Referring to fig. 1C, at a transmitting end, an RF system 170 includes a Dedicated Physical Channel (DPCH) block 126, a plurality of mixers 128, 130, and 132, a plurality of combiners 134 and 136, a first antenna switch (SW1)135, a second antenna switch (SW2)137, a first set of transmit antennas 138 and 140, a second set of antennas 139 and 141, and an antenna controller 145. At the receiving end, the RF system 170 includes multiple receive antennas 106_1。。。MA Single Weight Generator (SWG)110, a plurality of RF modules 114_1。。。PA plurality of Chip Matched Filters (CMFs) 116_1。。。PAnd a baseband (BB) processor 126.

The DPCH 126 is used to receive a plurality of input channels, e.g., a Dedicated Physical Control Channel (DPCCH) and a Dedicated Physical Data Channel (DPDCH). The DPCH 126 may control the power of the DPCCH and DPDCH simultaneously. The mixer 128 is used to mix the output of the DPCH 126 with the spread and/or scrambled signal to generate a spread complex-valued signal that is input to mixers 130 and 132. Mixers 130 and 132 may couple the complex-valued input signal with a weighting factor W, respectively₁And W₂Weighted and generate outputs to a plurality of combiners 134 and 136, respectively. Combiners 134 and 136 combine the outputs generated by mixers 130 and 132 with common pilot channel 1(CPICH1) and common pilot channel 2(CPICH2), respectively. Common pilot channels 1 and 2 have fixed channel code configurations and can be used to measure the phase amplitude signal strength of the channelAnd (4) degree.

SW1135 and SW2137 may comprise suitable logic, circuitry, and/or code and may be operable to select signals from two output ports, one of which may be coupled to an input port. SW1135 and SW2137 may be implemented with Single Pole Double Throw (SPDT) switching devices or with Multiplexers (MUXs). The selection operation of SW1135 and SW2137 may be controlled by a control signal, such as a transmit control (TX _ CTL) signal generated by antenna controller 145. SW1135 may be used to alternately switch between multiple antennas 138 and 139 to transmit communication signals from the multiple antennas. SW2137 is used to alternately switch between the multiple antennas 140 and 141 to transmit communication signals from the multiple antennas.

The plurality of antennas 138, 139, 140, and 141 may comprise suitable logic, circuitry, and/or code that may enable communication signals to be transmitted. In this regard, multiple antennas 138, 139, 140, and 141 may be used to communicate multiple communication protocols. The multiple antennas 138, 139, 140, and 141 may be configured to provide spatial and/or temporal isolation. Polarized antennas 138, 139, 140, and 141 may reduce the space between the antennas, providing isolation. The first group of antennas 138 and 140 or the second group of antennas 139 and 141 may receive the generated outputs from the combiners 134 and 136 and transmit wireless signals according to the positions of SW1135 and SW2137 of the switched antennas.

Multiple receive antennas 106_1。。。MAt least a portion of the transmitted signal may be received. The SWG 110 may comprise suitable logic, circuitry, and/or code that may enable determination of the input signals R to be applied to_1。。。MA plurality of weights. SWG 110 is used to modify multiple receive antennas 106_1。。。MReceiving a portion of the transmitted signal in phase and amplitude and generating a plurality of output signals RF_1。。。P。

Multiple RF modules 114_1。。。PMay comprise suitable logic, circuitry, and/or code that may enable processing of RF signals. RF module 114_1。。。PFiltering, amplification and analog-to-digital (AD) conversion operations, for example, may be performed. The multiple transmit antennas 138 and 140 may transmit the processed RF signals to the multiple receive antennas 106_1。。。M. The Single Weight Generator (SWG)110 may comprise suitable logic, circuitry, and/or code that may enable determination of a plurality of weights that may be applied to each input signal. Single weight generator SWG 110 for modifying multiple receive antennas 106_1。。。MReceiving a portion of the signal in phase and amplitude and generating a plurality of output signals RF_1。。。P. Multiple RF receiving modules 114_1。。。PMay comprise suitable logic, circuitry and/or code that may enable RF communication of received analog RF signals_1。。。PAmplified and down-converted to baseband. Multiple RF receiving modules 114_1。。。PEach of which includes an analog-to-digital (a/D) converter for digitizing the received analog baseband signal.

Multiple Chip Matched Filters (CMFs) 116_1。。。PMay comprise suitable logic, circuitry and/or code that may enable a plurality of RF receive modules 114 to be coupled to_1。。。PTo generate in-phase (I) and quadrature (Q) components (I, Q). In this regard, in an embodiment of the present invention, a plurality of Chip Matched Filters (CMFs) 116_1。。。PA pair of digital filters may be included for filtering the I and Q components. Multiple Chip Matched Filters (CMFs) 116_1。。。PMay be transmitted to the BB processor 126.

The BB processor 126 is used for multiple Chip Matched Filters (CMFs) 116_1。。。PReceiving a plurality of in-phase and quadrature components (I, Q) and generating a plurality of baseband combined channel estimatesTo. The BB processor 126 is configured to generate an initial input spatial multi-path substream signal or symbol X₁To X_PMultiple valuations ofTo. The BB processor 126 separates the different space-time channels using bell labs layered space-time algorithm (BLAST) by performing sub-stream detection and sub-stream cancellation. By using the BLAST algorithm, the transmission capacity is almost linearly increased.

Multiple Cluster Path Processors (CPP)118_1。。。PMay generate and receive multiple antennas 106_1。。。MCorresponding multiple baseband combined channel estimatesTo. The channel estimator 122 may comprise suitable logic, circuitry, and/or code that may enable processing of the estimate received from the BB processor 126ToAnd generating a matrix of the processed estimated channels

Fig. 2 is a block diagram of a typical Radio Frequency (RF) receiver antenna architecture for an Orthogonal Frequency Division (OFD) based system according to an embodiment of the present invention. Referring to fig. 2, an RF receiver 200 is shown. RF receiver 200 includes a plurality of polarized antennas 210_1，2，…MAnd 211_1，2，…MA plurality of switches 209_1，2，…MA plurality of amplifiers 212_1，2，…MAntenna controller 223, weight generation module 214, and plurality of filters 220_1，2，…NA local oscillator 222, a plurality of mixers 224_1，2，…NA plurality of analog-to-digital (A/D) converters 226_1，2，…NAnd a baseband processor 230.

Multiple switches SW_1，2，…M209_1，2，…MMay comprise suitable logic, circuitry and/or code that may be adapted toOne of the signals from the two input ports is selected to be connected to the output port. Multiple switches SW_1，2，…M209_1，2，…MMay be implemented using, for example, Single Pole Double Throw (SPDT) switching devices, switching transistors, or using a Multiplexer (MUX). SW_1，2，…M209_1，2，…MMay be controlled by a control signal, such as a receive control (RX _ CTL) signal generated by antenna controller 223. Switch 1 (SW)₁)209₁Can be used in multiple antennas 210₁And 211₁Alternately switched to receive communication signals from multiple antennas. Similarly, switch M (SW)_M)209_MCan be used in multiple antennas 210_MAnd 211_MAlternately switched to receive communication signals from multiple antennas.

Multiple antennas 210_1，2，…MAnd 211_1，2，…MComprising suitable logic, circuitry, and/or code that may enable transmitting and receiving communication signals. In this regard, the plurality of antennas 210_1，2，…MAnd 211_1，2，…MMay be used to receive multiple communication protocols. Multiple antennas 210_1，2，…MAnd 211_1，2，…MMay be configured to provide spatial and/or temporal isolation. Antenna 210_1，2，…MAnd 211_1，2，…MMay be polarized to reduce the space between the antennas to provide isolation. The first set of antennas 207, 210 may be selected_1，2，…MOr a second set of antennas 205, 211_1，2，…MTo switch 209 according to a plurality of antennas_1，2，…MThe selected antenna group receives a wireless signal.

According to an embodiment of the invention, a plurality of antennas proximate to at least one polarized antenna are orthogonally polarized with respect to its adjacently placed polarized antennas. For example, antenna 1210₁Polarized at a polarization angle of 0 degrees. Antenna 2210₂Relative to the antenna 1210₁Are orthogonally polarized with a polarization angle of 90 degrees. Antenna 3210₃Relative to antenna 2210₂Is orthogonally polarized with respect to antenna 1210₁Is coherently polarized with a polarization angle of 0 degrees or 180 degrees. Similarly, e.g. antennasM-1 210_M-1There is a polarization angle of 0 degrees. Antenna M-2210_M-2And antenna M210_MRelative to antenna M-1210_M-1Are orthogonally polarized, each with a polarization angle of 90 degrees.

Multiple coherently polarized antennas, antenna 1210₁Antenna 3210₃And an antenna 5210₅Are placed at a certain distance d1 from each other. Multiple coherently polarized antennas, antenna 2210₂And an antenna 4210₄And an antenna 6210₆Are placed at a certain distance d2 from each other. In an embodiment of the present invention, the specific distance d1 may or may not be equal to the specific distance d 2.

Amplifier 212_1，2，…MFor amplifying the M received input RF signals. The weight generation module 214 includes a plurality of amplitude and phase converters to compensate for phase differences between the respective received input RF signals. Weights being applied to each input signal A_1…MTo modify multiple receive antennas 210_1，2，…MThe phase and amplitude of a received portion of the transmitted signal and generating a plurality of output signals RF_1…N. Multiple filters 220_1，2，…NFor filtering the frequency components of the RF substreams. Mixer 224_1，2，…NFor downconverting the analog RF substream to baseband. Local oscillator 222 is used to provide a signal to mixer 224_1，2，…NA mixer 224_1，2，…NFor downconverting the analog RF substream to baseband. Analog-to-digital (A/D) converter 226_1，2，…NFor converting the analog baseband sub-streams into their corresponding digital sub-streams. The baseband processor 230 is configured to process the digital baseband substreams and multiplex the plurality of digital signals to generate an output signal.

In operation, an RF signal is received by M polarized antennas 210 at receiver 200_1，2，…MOr 211_1，2，…MAnd receiving. Each of the M received signals is amplified by a respective low noise amplifier 210_1，2，…MAnd (4) amplifying. Multiple weights may be applied to each input signal A_1…MTo modify multiple receive antennas 212_1…MIs received byA portion of the transmit signal. Generated plurality of output signals RF_1…NBy a plurality of filters 220_1，2，…NAnd (6) filtering. And then using N mixers 224_1，2，…NThe resulting N filtered signals are downconverted to baseband, with each mixer being provided with a carrier signal generated by a local oscillator 222. Next, a plurality of analog-to-digital (A/D) converters 226_1，2，…NThe mixer 224_1，2，…NThe generated N baseband signals are converted into digital signals. The N digital signals are further processed by the baseband processor 230 to generate output signals.

In one embodiment of the present invention, baseband processor 230 operates according to one or more standards including, but not limited to, IEEE802.11, Bluetooth, ZigBee, Advanced Mobile Phone Service (AMPS), Global System for Mobile communications (GSM), Code Division Multiple Access (CDMA), Local Multipoint Distribution System (LMDS), Worldwide Interoperability for Microwave Access (WiMAX), fourth Generation (4G), Orthogonal Frequency Division Multiplexing (OFDM) based systems, digital video broadcasting for Handheld (DVB-H), Multi-channel multipoint distribution System (MMDS), Global Positioning System (GPS), Frequency Modulation (FM), enhanced data rates for GSM evolution (EDGE), and/or variations thereof.

Fig. 3A is a schematic diagram of a typical antenna architecture of a multi-antenna Orthogonal Frequency Division (OFD) based system according to an embodiment of the present invention. Referring to fig. 3A, an RF system 300 is shown including multiple antennas, namely antenna 1302, antenna 2304, antenna 3306, antenna 4308, antenna 5310, and antenna 6312.

The plurality of antennas, i.e., antenna 1302, antenna 2304, antenna 3306, antenna 4308, antenna 5310, and antenna 6312 may comprise suitable logic, circuitry, and/or code that may be enabled to transmit and receive RF communication signals. In this regard, the plurality of antennas, i.e., antenna 1302, antenna 2304, antenna 3306, antenna 4308, antenna 5310, and antenna 6312, may be used to transmit and receive a plurality of communication protocols including, but not limited to, IEEE802.11, bluetooth, Advanced Mobile Phone Service (AMPS), global system for mobile communications (GSM), Code Division Multiple Access (CDMA), Local Multipoint Distribution System (LMDS), Worldwide Interoperability for Microwave Access (WiMAX), fourth generation (4G), orthogonal frequency division multiplexing (OFDM based systems, digital video broadcasting-handheld (DVB-H), Multichannel Multipoint Distribution System (MMDS), Global Positioning System (GPS), Frequency Modulation (FM), enhanced data rates for GSM evolution (EDGE), and/or variations thereof.

The antenna 1302 is polarized at a polarization angle of, for example, 0 degrees. Antenna 2304 is orthogonally polarized with respect to antenna 1302, with a polarization angle of 90 degrees. Antenna 3306 is orthogonally polarized with respect to antenna 2304 and coherently polarized with respect to antenna 1302, with a polarization angle of 0 degrees or 180 degrees. Similarly, antenna 4308 has a polarization angle of 90 degrees, antenna 5310 has a polarization angle of 0 degrees or 180 degrees, and antenna 6312 has a polarization angle of 90 degrees. The plurality of coherently polarized antennas, antenna 1302, antenna 3306, and antenna 5310, are placed a certain distance d1 from each other. The plurality of coherently polarized antennas, antenna 2304, antenna 4308, and antenna 6312, are placed a certain distance d2 from each other. In an embodiment of the present invention, the specific distance d1 may or may not be equal to the specific distance d 2.

Multiple antennas, namely antenna 1302, antenna 2304, antenna 3306, antenna 4308, antenna 5310, and antenna 6312, may be configured to provide spatial and/or temporal isolation. Polarized antennas, i.e., antenna 1302, antenna 2304, antenna 3306, antenna 4308, antenna 5310, and antenna 6312, may achieve a reduction in the separation space between the antennas and provide isolation.

Fig. 3B is a schematic diagram of another exemplary antenna architecture of a multiple antenna Orthogonal Frequency Division (OFD) based system according to an embodiment of the present invention. Referring to fig. 3B, an RF system 300 is shown including a plurality of antennas arranged in a matrix 350. Each cell in the matrix includes a polarized antenna.

The antenna 1 in the first cell 362 is polarized at a polarization angle of, for example, 0 degrees. Antenna 2 in the adjacent cell 364 is orthogonally polarized, with a polarization angle of 90 degrees, with respect to antenna 1 in the first cell 362. Antenna 3 in the third cell 366 is orthogonally polarized with respect to antenna 1 in cell 362 and coherently polarized with respect to antenna 2 in cell 364, with a polarization angle of 90 degrees. Similarly, antenna 4 in cell 368 is coherently polarized with respect to antenna 1 in cell 362, orthogonally polarized with respect to antenna 2 in cell 364 and antenna 3 in cell 366, with a polarization angle of 0 degrees or 180 degrees. Antenna 5 in cell 370 is coherently polarized with respect to antenna 4 in cell 368 and orthogonally polarized with respect to antenna 3 in cell 366, with a polarization angle of 0 degrees or 180 degrees. Antenna 6 in cell 372 is orthogonally polarized, having a polarization angle of 90 degrees, with respect to antenna 5 in cell 370.

The plurality of coherently polarized antennas, antenna 1 in cell 362, antenna 4 in cell 368, and antenna 5 in cell 370, are placed a certain distance d1 from each other. The plurality of coherently polarized antennas, antenna 2 in cell 364 and antenna 3 in cell 366, are placed at a certain distance d2 from each other. The plurality of coherently polarized antennas, antenna 3 in cell 366 and antenna 6 in cell 372, are placed a certain distance d2 from each other. In an embodiment of the present invention, the specific distance d1 may or may not be equal to the specific distance d 2.

Fig. 4 is a schematic block diagram of a typical switching mechanism in an Orthogonal Frequency Division Multiplexing (OFDM) -based multiple-input multiple-output (MIMO) system according to an embodiment of the present invention. Referring to fig. 4, a portion of an RF system 400 is shown including a plurality of antenna switches, namely switch 1410, switch 2412, switch 3141 and switch 4416, a first set of antennas 420 and a second set of antennas 430. The first set of antennas 420 includes multiple antennas, namely antenna 1422, antenna 2424, antenna 3426, and antenna 4428. The second set of antennas 430 includes multiple antennas, namely antenna 5432, antenna 6434, antenna 7436, and antenna 8438.

The plurality of antenna switches, i.e., switch 1410, switch 2412, switch 3141, and switch 4416 may comprise suitable logic, circuitry, and/or code that may be enabled to select signals from two input ports, one of which may be coupled to an output port. The plurality of switches, i.e., switch 1410, switch 2412, switch 3141, and switch 4416, may be implemented using, for example, Single Pole Double Throw (SPDT) switching devices, switching transistors, or using a Multiplexer (MUX). The selective operation of the plurality of antenna switches, i.e., switch 1410, switch 2412, switch 3141, and switch 4416, may be controlled by a control signal, such as a transmit control (TX _ CTL) signal or a receive control (RX _ CTL) signal, generated by antenna controller 405.

For example, switch 1410 is used to alternately switch between multiple antennas, antenna 1422 and antenna 5432, to transmit and receive communication signals to and from the multiple antennas. Switch 2412 may be used to alternately switch between multiple antennas, antenna 2424 and antenna 6434, to transmit and receive communication signals to and from the multiple antennas. Switch 3414 may be used to alternately switch between the multiple antennas, i.e., antenna 3426 and antenna 7436, to transmit communication signals to or receive communication signals from the multiple antennas. Switch 4416 may be used to alternately switch between multiple antennas, antenna 4428 and antenna 8438, to transmit to and receive communication signals from the multiple antennas.

The plurality of antennas, i.e., antenna 1422, antenna 2424, antenna 3426, antenna 4428, antenna 5432, antenna 6434, antenna 7436, and antenna 8438, may comprise suitable logic, circuitry, and/or code that may enable the transmission and reception of communication signals. In this regard, the multiple antennas, antenna 1422, antenna 2424, antenna 3426, antenna 4428, antenna 5432, antenna 6434, antenna 7436, and antenna 8438 may be used to transmit and/or receive multiple communication protocols. Multiple antennas, antenna 1422, antenna 2424, antenna 3426, antenna 4428, antenna 5432, antenna 6434, antenna 7436, and antenna 8438 may be configured to provide spatial and/or temporal isolation. Multiple antennas, antenna 1422, antenna 2424, antenna 3426, antenna 4428, antenna 5432, antenna 6434, antenna 7436, and antenna 8438 may be polarized to reduce the spatial separation between the antennas, providing isolation. The first set of antennas 420 or the second set of antennas 430 may be selected to transmit and/or receive communication signals based on the set of antennas selected by the plurality of antenna switches, i.e., switch 1410, switch 2412, switch 3141, and switch 4416.

According to an embodiment of the present invention, a plurality of antennas placed close to at least one polarized antenna are orthogonally polarized with respect to its adjacently placed polarized antennas. For example, antenna 1422 is polarized at a polarization angle of 0 degrees. Antenna 2424 is orthogonally polarized with respect to antenna 1422, having a 90 degree polarization angle. Antenna 3426 is orthogonally polarized with respect to antenna 2424 and coherently polarized with respect to antenna 1422, with a polarization angle of 0 degrees or 180 degrees. Antenna 4428 was orthogonally polarized with respect to antenna 3426, with a polarization angle of 90 degrees. Similarly, for example, antenna 5432 is polarized at a polarization angle of 90 degrees. Antenna 6434 is orthogonally polarized with respect to antenna 5432, with a polarization angle of 0 degrees. Antenna 7436 is orthogonally polarized with respect to antenna 6434 and coherently polarized with respect to antenna 5432, with a polarization angle of 90 degrees. Antenna 8438 is orthogonally polarized with respect to antenna 7436 and coherently polarized with respect to antenna 6434, with a polarization angle of 0 degrees or 180 degrees.

The plurality of coherently polarized antennas, antenna 1422 and antenna 3426, are placed a certain distance d1 from each other. The plurality of coherently polarized antennas, antenna 2424 and antenna 4428, are placed a certain distance d2 from each other. Similarly, multiple coherently polarized antennas, antenna 5432 and antenna 7436, may be placed a particular distance d1 from each other. A plurality of coherently polarized antennas, antenna 6434 and antenna 8438, are placed a certain distance d2 from each other. In an embodiment of the present invention, the specific distance d1 may or may not be equal to the specific distance d 2. In addition to the two sets of antennas shown in fig. 4, the RF system 400 may include multiple sets of antennas, and each switch may switch between multiple antennas.

In accordance with an embodiment of the present invention, a method and system for an Orthogonal Frequency Division Multiplexing (OFDM) -based multiple-input multiple-output (MIMO) system with enhanced diversity includes a plurality of antenna switches, switch 1410, switch 2412, switch 3141, and switch 4416 within a Radio Frequency (RF) system 400 that includes a plurality of antennas, e.g., antenna 1422, antenna 2424, antenna 3426, antenna 4428, antenna 5432, antenna 6434, antenna 7436, and antenna 8438, for selecting at least one set of antennas, e.g., a first set of antennas 420 or a second set of antennas 430.

The selected antenna group, e.g., first group of antennas 420, can include at least one polarized antenna, e.g., antenna 1422, that is orthogonally polarized with respect to an adjacent polarized antenna (e.g., antenna 2424). The polarized antenna (e.g., antenna 1422) is positioned a particular distance d1 from at least one other polarized antenna (e.g., antenna 3426) that is coherently polarized with respect to the polarized antenna (i.e., antenna 1422). An adjacent polarized antenna, antenna 2424, is positioned a particular distance d2 from at least one other polarized antenna (i.e., antenna 4428) that is coherently polarized with respect to the adjacent polarized antenna (i.e., antenna 2424).

At least one polarized antenna (antenna 3426) that is orthogonally polarized with respect to adjacent polarized antennas (antenna 2424 and antenna 4428) is used for transmitting and/or receiving data. A plurality of antenna switches, i.e., switch 1410, switch 2412, switch 3141, and switch 4416, are used to switch between a plurality of selected antenna groups, e.g., the first group of antennas 420 or the second group of antennas 430. The plurality of antenna switches, i.e., switch 1410, switch 2412, switch 3141, and switch 4416, may select at least one antenna from the selected set of antennas to transmit data. For example, switch 1410 is used to alternately switch between multiple antennas, antenna 1422 and antenna 5432, to transmit and/or receive communication signals to and/or from the multiple antennas. Switch 2412 is operable to alternately switch between multiple antennas, antenna 2424 and antenna 6434, to transmit and/or receive communication signals from the multiple antennas.

Another embodiment of the present invention provides a machine-readable storage having stored thereon a computer program having at least one code section executable by a machine, the machine being caused to perform the above steps for a multiple-input multiple-output (MIMO) system based on Orthogonal Frequency Division Multiplexing (OFDM) and having enhanced diversity. For example, any one or more components of wireless communication master device 10 and/or RF subsystem 60 may be controlled by code such as software and/or firmware. In this regard, any one or more of the digital receiver processing module 64, the ADC 66, the filtering/gain module 68, the down conversion module 70, the LNA 72, and the Rx filtering module 71 may be programmably controlled by code comprising software and/or firmware in an exemplary embodiment of the invention. In another exemplary embodiment of the present invention, any one or more of the transmitter processing module 76, DAC 78, filter/gain module 80, up-conversion module 82, PA 84, and Tx filtering module 86 may be programmably controlled by code comprising software and/or firmware.

Accordingly, the present invention may be realized in hardware, software, or a combination of hardware and software. The present invention may be practiced in a centralized fashion in at least one computer system, or in a distributed fashion where elements are spread across different interconnected computer systems. Any kind of computer system, or other apparatus adapted for carrying out the methods described herein, is suited to use the invention. An example of a combination of hardware and software can be a general-purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein.

The present invention can also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to other languages, code or notation; b) regenerated in other forms.

While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A method of processing signals in a communication network, the method comprising:

in a radio frequency system comprising a plurality of antennas, selecting at least one group of antennas from the plurality of antennas;

transmitting data through the selected at least one set of antennas, the at least one set of antennas including at least one polarized antenna that is orthogonally polarized with respect to an adjacent polarized antenna;

placing the at least one polarized antenna at a specific distance from at least one other polarized antenna, the at least one other polarized antenna being coherently polarized with respect to the at least one polarized antenna, or the at least one other polarized antenna being coherently polarized with respect to the adjacent polarized antenna.

2. The method of claim 1, further comprising transmitting the data through the at least one polarized antenna that is orthogonally polarized relative to an adjacent polarized antenna.

3. The method of claim 1, further comprising receiving the data via the at least one polarized antenna that is orthogonally polarized with respect to an adjacent polarized antenna.

4. A system for processing signals in a communication network, the system comprising:

at least one circuit in the radio frequency system for selecting at least one group of antennas from a plurality of antennas; and is

The at least one circuit transmits data through the selected at least one group of antennas, wherein the selected at least one group of antennas includes at least one polarized antenna that is orthogonally polarized with respect to adjacent polarized antennas, the at least one polarized antenna is placed a certain distance from at least one other polarized antenna, the at least one other polarized antenna is coherently polarized with respect to the at least one polarized antenna, or the at least one other polarized antenna is coherently polarized with respect to each of the adjacent polarized antennas.