WO2009021247A1

WO2009021247A1 - Methods and system for multi-service multi-band radio signal channelizer

Info

Publication number: WO2009021247A1
Application number: PCT/US2008/075140
Authority: WO
Inventors: Bijan Rohani; Kambiz Homayounfar
Original assignee: Phybit Pte. Ltd.
Priority date: 2008-09-03
Filing date: 2008-09-03
Publication date: 2009-02-12

Abstract

Methods and a system for providing a multi-service multi-band radio signal are provided. A method includes receiving a multi-service multi-band radio signal that includes a frequency spectrum of a wireless service by a channelizer path, frequency translating the frequency spectrum of the wireless service to an intermediate frequency associated with the channelizer path, digitizing the single multiple service carrying signal using a wideband analog-to-digital converter (ADC), and outputting the digitized signal.

Description

METHODS AND SYSTEM FOR MULTI-SERVICE MULTI- BAND RADIO SIGNAL CHANNELIZER

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to providing wireless services and, more particularly, to methods and a system for a multi-service multi-band radio signal channelizer.

[0002] Existing and future wireless communications standards provide a multitude of services ranging from basic mobile telephony to ubiquitous broadband internet access. Such standards include GSM, CDMA2000, UMTS WCDMA, IEEE-802.Ha/g/e/n, WiMAX, 3G LTE, XG-PHS, DTV, and DAB. At least some known transceivers are designed; or can be reconfigured in hardware, specifically to suit a particular service and standard for each implementation. As such, in order to draw on multiple heterogeneous services, several transceivers are necessary; one for each service. This leads to increased space, number of antennas, power consumption, and hardware cost.

[0003] One approach to multi-service transceiver design adopts software defined radio (SDR). In SDR, both RF and baseband parts of the transceiver are made reconfϊgurable by means of programming software so as to accommodate a wide range of wireless standards and services. This allows a high level of component reuse hence savings in space and hardware cost. In addition, new standards can be added without much redesign.

[0004] With the current limits of SDR technology it is not practical to design a single RF front-end that is capable of receiving the full range of wireless standards and services. Instead, the range of frequencies occupied by these services can be partitioned into multiple bands so each band is narrow enough to fall within the capabilities of the exciting SDR technology. Such an approach requires a number of independent SDRs; one for each band. The resulting architecture can provide a multi-service multi-band solution for a wide range of wireless services and standards. In addition, the output of the SDRs can be frequency multiplexed to predefined intermediate frequency (IF) channels so that a single wideband analog-to-digital converter (ADC) is sufficient for digitizing the combined signals. An example of the usage of this multi-service multi-band radio signal channelizer is in multi-service receivers for automobiles. In this approach, the existing method can receive only on a single frequency per each RF front-end receive path. Such an approach limits the number of services that can be accommodated per receive path to only one; and hence, imposes a limitation of the number of services as a trade-off versus the size and cost of the hardware as well as multiple transceiver designs and implementations.

BRIEF DESCRIPTION OF THE INVENTION

[0005] In one embodiment, a method for providing a multi-service multi-band radio signal includes receiving a multi-service multi-band radio signal that includes a frequency spectrum of a wireless service by a channelizer path, frequency translating the frequency spectrum of the wireless service to an intermediate frequency associated with the channelizer path, digitizing the single multiple service carrying signal using a wideband analog-to-digital converter (ADC), and outputting the digitized signal

[0006] In another embodiment, a method of receiving wireless service data includes receiving a multi-service multi-band radio signal at an antenna, splitting the multi-service multi-band radio signal among a plurality of independent and simultaneously operating channelizer paths, and partitioning, by each of the channelizer paths, a frequency spectrum of a wireless service in the split multi-service multi-band radio signal into multiple non overlapping bands. The method also includes frequency translating the frequency spectrum of the wireless service to an intermediate frequency associated with the channelizer path and combining the translated wireless service with a translated wireless service from a different one of the plurality of channelizer paths to form a single signal carrying multiple services. The method further includes digitizing the single multiple service carrying signal using a wideband analog-to-digital converter (ADC) and outputting the digitized signal. [0007] In yet another embodiment, a multi-service multi-band radio signal channelizer includes an input configured to receive a multi-service multi-band radio signal and a radio frequency (RF) splitter communicatively coupled to the antenna. The radio frequency splitter is configured to split the multi-service multi- band radio signal into a plurality of frequency bands. The channelizer also includes a plurality of channelizer paths wherein each channelizer path is configured to operate independently of and simultaneously with each other of the operating channelizer paths. Each channelizer path is further configured to receive at least one of the plurality of frequency bands, partition a frequency spectrum of a wireless service in the received at least one of the plurality of frequency bands, and downconvert the frequency spectrum of the wireless service to an intermediate frequency associated with the channelizer path. The channelizer also includes a combiner configured to combine the intermediate frequencies from a plurality of the channelizer paths to form a single frequency multiplexed signal that includes a plurality of services simultaneously.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figures 1-6 show exemplary embodiments of the methods and system described herein.

[0009] Figure 1 is a schematic block diagram of a multi-service multi-band radio signal channelizer;

[0010] Figure 2 is another block diagram of multi-service multi-band simultaneous radio signal channelizer shown in Figure 1 in accordance with an exemplary embodiment of the present invention;

[0011] Figure 3 A is a diagram of an exemplary frequency spectrum at an input of the channelizer;

[0012] Figure 3B is a diagram of an exemplary frequency spectrum of intermediate frequencies at an output of the channelizer; [0013] Figure 4 is a schematic block diagram of high level main components of the channelizer;

[0014] Figure 5 is an enlarged schematic block diagram of main components of the channelizer in greater detail; and

[0015] Figure 6 is a schematic block diagram of the multi-service multi-band radio signal channelizer in use in an automotive application.

DETAILED DESCRIPTION OF THE INVENTION

[0016] The following detailed description illustrates embodiments of the invention by way of example and not by way of limitation. It is contemplated that the invention has general application to statistical, analytical, and methodical embodiments of a multi-service multi-band radio signal channelizer in industrial, commercial, and residential applications.

[0017] As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to "one embodiment" of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0018] Figure 1 is a schematic block diagram of a multi-service multi-band radio signal channelizer 100 in accordance with an exemplary embodiment of the present invention. In the exemplary embodiment, channelizer 100 includes a plurality of independent and simultaneously operating Channelizer Paths, Channelizer Path 102, Channelizer Path 104, and Channelizer Path 106. Each Channelizer Path 102, 104, and 106 includes circuitry for partitioning a frequency spectrum 108 including a plurality wireless services, Service#l 110, Service#2 112, ..., Service#p 114 into multiple non-overlapping bands, Band#l 116, Band#2 118, and Band#3 120. Each band includes one or more wireless services and is selectably allocated for processing by one of Channelizer Paths 102, 104, or 106. Each Channelizer Path 102, 104, or 106 selects one of the services in its allocated band and frequency translates it to the specific intermediate frequency (IF) channel for that Channelizer Path. The channelized outputs 122, 124, and 126 from all Channelizer Paths 102, 104, and 106, respectively are combined in a signal combiner 128 to form a single signal carrying multiple services through a conduit 130. The resulting signal is digitized by a wideband analog-to-digital converter (ADC) 132.

[0019] Figure 2 is another block diagram of multi-service multi-band simultaneous radio signal channelizer 100 (shown in Figure 1) in accordance with an exemplary embodiment of the present invention. In the exemplary embodiment, a broadband radio signal r{t) received from an antenna 202 is split into three parallel branches 204, 206, and 208. Each branch 204, 206, and 208 is processed by a respective software reconfigurable radio front-end shown as Channelizer Path 102, Channelizer Path 104, and Channelizer Path 106 in Figure 2. Each Channelizer Path includes an associated bandwidth that covers a portion of the overall received broadband radio signal; and can process at least one of the plurality of services that are assigned to it. However, in the exemplary embodiment, Channelizer Paths 102, 104, and 106 collectively cover a frequency range of for example, between approximately 400 MHz and approximately 7.5 GHz; and multiples of services that are processed simultaneously. In another embodiment of the invention a wider range of frequencies and higher number of services can be covered by adding more Channelizer Paths in parallel or upgrading the design of the individual Channelizer Paths to process wider bandwidths.

[0020] In one embodiment of the invention, each Channelizer Path 102, 104, and/or 106 selects the desired wireless service from within its assigned bands and channelizes it to its output. The three Channelizer Path outputs are denoted as Xi(O, xi(t), and x?,{t), respectively in Figure 2, and are configured through means of programming in software to have fixed intermediate frequencies associated with the desired services. The output signals are frequency multiplexed before sending to ADC 132 as shown in Figure 2. [0021] In another embodiment of the invention; by reconfiguring the functional blocks of each Channelizer Path in hardware or through means of programming in software, other frequencies can be selected to process other services and standards. In such embodiment, even a higher number of services can be accommodated per Channelizer Path.

[0022] In yet another embodiment of the invention, other methods of combining the outputs of the Channelizer Paths are implemented before sending to ADC 132.

[0023] Figure 3 A is a diagram of an exemplary frequency spectrum at an input of channelizer 100. Figure 3B is a diagram of an exemplary frequency spectrum of intermediate frequencies at an output of the channelizer 100. The frequency spectrum of the input RF signal r{t) to channelizer 100 is shown in Figure 3 A. The input signal includes a plurality of wireless services spanning a frequency range from approximately 400 MHz to approximately 5.8 GHz. For example, a digital television (DTV) service 302 is illustrated at an approximate frequency of 400 MHz, a global system for mobile communications (GSM) service 304 is illustrated at an approximate frequency of 900 MHz, a Worldwide Interoperability for Microwave Access (WiMAX) service 306 is illustrated at an approximate frequency of 2.4 GHz, a third generation system long term evolution (3G LTE) service 308 is illustrated at an approximate frequency of 2.5 GHz, and a dedicated short range communications (DSRC) service 310 is illustrated at an approximate frequency of 5.8 GHz. In this example three of the five exemplary input services are selected and the channelizer outputs xi(0, xi(t), and X₃(O represent DTV 302, DSRC 310, and WiMAX 306 signals, respectively. The corresponding intermediate frequencies of these selected three services which are simultaneously available at the channelizer output are shown in Figure 3B. The output signals are shown to have center frequencies of IFi= 5.35 MHz, IF₂= 16.06 MHz, and IF₃= 32.10 MHz, within the intermediate frequency bands of 2.35 MHz to 8.35 MHz, 11.06 MHz to 21.06 MHz, and 22.10 MHz to 42.10 MHz; respectively. [0024] Figure 4 is a schematic block diagram of the high level main components of channelizer 100. The received wideband signal from antenna 202 is split between Channelizer Paths 102, 104, and 106 using a radio frequency (RF) signal splitter 402. In the exemplary embodiment, antenna 202 is a wideband antenna capable of receiving signals in the range of approximately 400 MHz to approximately 7.5 GHz. Each Channelizer Path 102, 104, and 106 includes a low noise amplifier (LNA) 404, a reconfigurable filter 406, and a down converter 408. Each Channelizer Path 102, 104, and 106 is capable of channelizing one or more services that are assigned to it in the assigned frequency ranges of the corresponding services. The assigned service and the operating parameters of each Channelizer Path's components are configured by the means of software programming.

[0025] The received RF signal is first split by RF splitter 402 and the split signals are fed into each respective Channelizer Path 102, 104, or 106. Each split RF signal is then amplified by LNA 404 of its channelizer path. The amplified signal in each path is filtered to isolate the frequency ranges associated with the selected service to be processed. The filtered signal of each path is downconverted and fixed to the intermediate frequency selected for the service that is being processed.

[0026] The intermediate frequencies are fixed and distinct for each Channelizer Path 102, 104, or 106 (shown in Figure 4) and are determined such that interference among the channels from Channelizer Paths 102, 104, and 106 is minimized. In a similar way, all Channelizer Paths 102, 104, and 106 channelize the signals of the services that are assigned to them simultaneously.

[0027] In one embodiment of the present invention, the three output IF signals are combined providing a frequency multiplexed signal that includes the three simultaneous services. The resulting signal is next digitized using only one wideband analog-to-digital converter ADC 132.

[0028] In another embodiment of the invention other service types and number of services are processed by channelizer 100 in the manner described above. In yet another embodiment of the invention, other means of combining the resulting output IF signals are implemented and utilized.

[0029] Figure 5 is an enlarged schematic block diagram of the main components of channelizer 100 in greater detail. In the exemplary embodiment, each of Channelizer Paths 102, 104, and 106 includes low noise amplifier (LNA) 404, a reconfigurable highpass filter (HPF) 502, an RF amplifier 504, a lowpass filter (LPF) 506, a mixer 508, and a fixed LPF 510. For convenience, the operation of Channelizer Path 102 is described in detail. The remaining Channelizer Paths, 104 and 106, operate similarly to Channelizer Path 102.

[0030] Channelizer Path 102 is capable of channelizing services in the frequency range between approximately 400 MHz and approximately 2.5 GHz. In the exemplary embodiment, DTV and GSM mobile telephone services which are located in 400 MHz and 900 MHz bands, respectively are channelized by Channelizer Path 102. The services that are channelized by Channelizer Paths 104 and 106 in addition to their relevant frequency bands are summarized in Figure 5.

[0031] The received RF signal is first amplified by LNA 404. LNA 404 provides a gain of approximately G=20 dB with a noise figure approximately NF=2.1 dB over the frequency range of approximately 0.5 GHz to approximately 2.5 GHz. The combination of HPF 502 and LPF 506 provides a pass band of approximately 6 MHz over the frequency range from approximately 470 MHz to approximately 960 MHz. This provides sufficient frequency selectivity for channelizing any of the fifty DTV channels in the 400 MHz band. The passband is wide enough to allow approximately thirty GSM downlink channels in the 900 MHz band. Further bandpass filtering in the demodulation stage (not discussed here) will allow selecting the desired GSM downlink channel.

[0032] RF amplifier 504 provides additional RF gain of approximately 15 dB for the signal. The 6 MHz bandpass signal is next downconverted to the intermediate frequency IFi by mixer 508 with local oscillator frequency (LO) of from 475.35 MHz to approximately 965.35 MHz as shown in Figure 5. Mixers 508 associated with Channelizer Paths 104, and 106 have different local oscillator frequencies. Filter 510 rejects out-of-band frequencies at the output of the mixer.

[0033] The intermediate frequencies are fixed and distinct for Channelizer Paths 102, 104, and 106. In this example, IFi= 5.35 MHz is the center frequency of the IF channel for Channelizer Path 102. The IF channel frequencies for Channelizer Paths 104, and 106 are shown in Figure 5. The intermediate frequencies are selected such that there is no interference among the channels of Channelizer Paths 102, 104, and 106.

[0034] Similarly, Channelizer Path 104 channelizes for example, any one of seven DSRC channels to its output. The IF channel for Channelizer Path 104 is centered at IF₂=16.05 MHz and has a bandwidth of 10 MHz, in this example.

[0035] Channelizer Path 106 can channelize for example, either of WiMAX or Super 3 G services to its output. The IF channel for Channelizer Path 106 is centered at IF3=32.10 MHz with a bandwidth of 20 MHz in this example.

[0036] Channelizer Paths 102, 104, and 106 are combined providing a frequency multiplexed signal 512 containing three simultaneous services on the conduit 130. The resulting signal is next digitized using wideband analog-to-digital converter ADC 132 as shown in Figure 5 at an exemplary sampling frequency of 93.6 MHz.

[0037] Figure 6 is a schematic block diagram of multi-service multi- band radio signal channelizer 100 in use in an automotive application. In the exemplary embodiment, channelizer 100 is used in the automotive application to increase the number of services received by a vehicle while minimizing the number of components, cables, and cost of the communication system. In this example there are a plurality of popular services and communication standards that are available to the vehicle; such as but not limited to third generation system long term evolution 502 (3GLTE), WiMAX, next generation- personal handy phone 502 (XG-PHS), digital video broadcasting-terrestrial 504 (DVB-T), digital audio broadcasting 506 (DAB), and DSRC 310. Channelizer 100 can select and process any number of the services simultaneously by the means described above and reconfigure its operations using software programming. The channelized signals are then combined in the combiner 128, and the combined channelized signals are delivered to ADC 132 by only one cable 602. The combined signals are then converted to the digital domain and transmitted in the digital form to a baseband circuit 604 by ADC 132. In baseband circuit 604 a programmable vehicular broadband chipset (VBC) processor 606 performs the physical layer (PHY) and medium access control (MAC) functions for all of the selected services and delivers the internet protocol (IP) data to one or more service application processors (SAP) 608 for final delivery of for example, but not limited to voice, TV, Radio, DSRC information, and Internet services to the vehicle and the passengers.

[0038] The term processor, as used herein, refers to central processing units, microprocessors, microcontrollers, reduced instruction set circuits (RISC), application specific integrated circuits (ASIC), logic circuits, and any other circuit or processor capable of executing the functions described herein.

[0039] As used herein, the terms "software" and "firmware" are interchangeable, and include any computer program stored in memory for execution by a processor, including RAM memory, ROM memory, EPROM memory, EEPROM memory, and non-volatile RAM (NVRAM) memory. The above memory types are exemplary only, and are thus not limiting as to the types of memory usable for storage of a computer program.

[0040] Multi-service multi-band radio signal channelizer 100 includes advantages over known SDRs in that channelizer 100 facilitates reducing the number of the modules, functional blocks, and components used to process multiple standard services and operates over a wider frequency range of several GHz. Channelizer 100 permits an extendable frequency range by adding additional channelizer paths or using wider bandwidth channelizer paths. Channelizer 100 simultaneously provides channelization for several services. The frequency gap between the simultaneously channelized services can be in excess of 1 GHz and the services that are channelized can be wideband. The channelized output is a single frequency multiplexed signal requiring minimal cabling and circuitry for interfacing. A single ADC and consequent digital baseband signal processing circuit is used for digitizing the channelized output. Channelizer 100 also supports reconfigurability by means of programming in software, which permits accommodating new standards without major redesign.

[0041] As will be appreciated based on the foregoing specification, the above-described embodiments of the disclosure may be implemented using computer programming or engineering techniques including computer software, firmware, hardware or any combination or subset thereof, wherein the technical effect is partitioning a frequency spectrum containing a plurality of wireless services into a plurality of non-overlapping frequency bands. Each band includes one or more of the wireless services and is processed by an associated channelizer path. Each channelizer path selects one of the services in its allocated band and frequency translates it to the specific IF channel for that channelizer path. The channelized outputs from all channelizer paths are combined in a combiner to form a single signal carrying multiple services. The resulting signal is digitized by a wideband ADC for transmission to a user of the wireless services. Any such resulting program, having computer-readable code means, may be embodied or provided within one or more computer-readable media, thereby making a computer program product, i.e., an article of manufacture, according to the discussed embodiments of the disclosure. The computer readable media may be, for example, but is not limited to, a fixed (hard) drive, diskette, optical disk, magnetic tape, semiconductor memory such as read-only memory (ROM), and/or any transmitting/receiving medium such as the Internet or other communication network or link. The article of manufacture containing the computer code may be made and/or used by executing the code directly from one medium, by copying the code from one medium to another medium, or by transmitting the code over a network.

[0042] The above-described embodiments of a methods and system of multi-service multi-band radio signal channelizer provides a cost-effective and reliable means for splitting data services between channelizer paths that frequency translate the services signal to a specific intermediate frequency associated with that channel, combining the translated signals and converting the combined signal in a single analog to digital converter for further transmission to a user. As a result, the methods and system described herein facilitate communicating a plurality of data services to a user using a single digital signal in a cost-effective and reliable manner.

[0043] While the disclosure has been described in terms of various specific embodiments, it will be recognized that the disclosure can be practiced with modification within the spirit and scope of the claims.

Claims

WHAT IS CLAIMED IS:

1. A method of providing a multi-service multi-band radio signal, said method comprising:

receiving a multi-service multi-band radio signal that includes a frequency spectrum of a wireless service by a channelizer path;

frequency translating the frequency spectrum of at least one wireless service to an intermediate frequency associated with the channelizer path;

digitizing the single multiple service carrying signal using a wideband analog-to-digital converter (ADC); and

outputting the digitized signal.

2. A method in accordance with Claim 1 wherein receiving a multi-service multi-band radio signal by a channelizer path comprises receiving a multi-service multi-band radio signal at an antenna.

3. A method in accordance with Claim 1 further comprising splitting the multi-service multi-band radio signal among a plurality of independent and simultaneously operating channelizer paths.

4. A method in accordance with Claim 1 further comprising selecting a channelizer path for at least one wireless service corresponding to an intermediate frequency associated with the at least one service.

5. A method in accordance with Claim 1 further comprising partitioning, by each of the channelizer paths, a frequency spectrum of a wireless service in the split multi-service multi-band radio signal into multiple non- overlapping bands.

6. A method in accordance with Claim 5 wherein each band includes one or more wireless services and is selectably allocated for processing by one of channelizer paths.

7. A method in accordance with Claim 1 further comprising combining the translated wireless service with a translated wireless service from a different one of the plurality of channelizer paths to form a single signal carrying multiple services.

8. A method in accordance with Claim 7 further comprising frequency multiplexing the combined signal prior to channeling the signal to the ADC.

9. A method in accordance with Claim 1 wherein frequency translating the frequency spectrum of the wireless service to an intermediate frequency comprises:

determining an intermediate frequency associated with a desired wireless service; and

selecting the intermediate frequency based on the determination.

10. A method of receiving wireless service data, said method comprising:

receiving a multi-service multi-band radio signal at an antenna;

splitting the multi-service multi-band radio signal among a plurality of independent and simultaneously operating channelizer paths;

partitioning, by each of the channelizer paths, a frequency spectrum of a wireless service in the split multi-service multi-band radio signal into multiple non-overlapping bands;

frequency translating the frequency spectrum of the wireless service to an intermediate frequency associated with the channelizer path;

combining the translated wireless service with a translated wireless service from a different one of the plurality of channelizer paths to form a single signal carrying multiple services; digitizing the single multiple service carrying signal using a wideband analog-to-digital converter (ADC) and

outputting the digitized signal.

11. A method in accordance with Claim 10 further comprising software selecting the intermediate frequency.

12. A method in accordance with Claim 10 further comprising software selecting one or more wireless services for channelizing by each channelizer path.

13. A method in accordance with Claim 10 further comprising filtering the split signal by each channelizer path such that the frequency ranges associated with the selected services to be processed are isolated from each other.

14. A method in accordance with Claim 13 wherein frequency translating the frequency spectrum of the wireless service to an intermediate frequency comprises downconverting the filtered signal of each channelizer path to the intermediate frequency selected for the service that is being processed.

15. A multi-service multi-band radio signal channelizer comprising:

an input configured to receive a multi-service multi-band radio signal;

a radio frequency (RF) splitter communicatively coupled to said antenna, said radio frequency splitter configured to split the multi-service multi-band radio signal into a plurality of frequency bands;

a plurality of channelizer paths, each channelizer path configured to operate independently of and simultaneously with each other of the operating channelizer paths, each channelizer path configured to:

receive at least one of the plurality of frequency bands; partition a frequency spectrum of a wireless service in the received at least one of the plurality of frequency bands;

downconvert the frequency spectrum of the wireless service to an intermediate frequency associated with the channelizer path; and

a combiner configured to combine the intermediate frequencies from a plurality of the channelizer paths to form a single frequency multiplexed signal that includes a plurality of services simultaneously.

16. A system in accordance with Claim 15 wherein said input comprises an antenna.

17. A system in accordance with Claim 15 further comprising:

a wideband analog-to-digital converter (ADC) communicatively coupled to said combiner, said ADC configured to digitize the single multiple service carrying signal; and

a channelizer output configured to output the digitized signal for further processing.

18. A system in accordance with Claim 17 further comprising a multiplexer communicatively coupled to said ADC, said multiplexer is configured to frequency multiplex the combined intermediate frequency signals prior to digitization by the ADC.

19. A system in accordance with Claim 15 further comprising filtering the split signal by each channelizer path such that the frequency ranges associated with the selected services to be processed are isolated from each other.

20. A system in accordance with Claim 15 further comprising:

a programmable vehicular broadband chipset (VBC) processor communicatively coupled to said ADC, said VBC processor configured to perform the physical layer (PHY) and media access controller (MAC) functions for the selected services in the digitized signal; and

a service application processor (SAP) communicatively coupled to said VBC processor, said SAP configured to receive internet protocol data for each of the selected services and channel the selected wireless services to a user.