CN100444529C - Variable sign/phase and inter-pulse time modulated multi-band UWB communication system - Google Patents

Abstract

A wireless communication system performs high-speed transmission of information signals by using a multi-band approach. Each band spans about 500MHz. A flexible modulation scheme within each band employs time, amplitude and phase modulations, allowing adaptation of the data rate to the sub-band conditions. In addition, pseudo-random frequency sequence is employed to provide sufficient multi-user interference reduction.

Description

Flexible symbol/phase place and modulation of interpulse time multi-band uwb communication system

Technical field

The present invention relates to high data rate communication system.More specifically, the present invention relates to be used for the system and method for ultra broadband (UWB) system of high data rate applications.The invention particularly relates to the multi-band UWB system that per second transports the multimegabit numerical data that is modulated into.

Background technology

Sometimes UWB is called impulse radio or zero-carrier technology.Pulsed radio system is characterised in that pulse train and the wideband pulse that has the short duration with low relatively duty cycle (being generally the 10-1000 psec) transmission.In some systems, the transient pulse bandwidth of these pulses is similar to centre frequency.

Conventional UWB communication system is emitted energy on the bandwidth bigger than arrowband or spread spectrum system.The burst signal that described system is designed to have by use very narrow pulse duration (being generally 1ns or littler) is carried out baseband transmission.

Because the low signal density of UWB, so it realizes other wireless system is produced less interference, and is expected to become the technology of the employed frequency band of wireless communication system that can cover prior art.In addition, because its super wide frequency band, UWB is expected to be used for the ultrahigh speed wireless transmission of personal area network's (PAN) the 100Mbps order of magnitude.This adopts the 3.1-10.6GHz frequency band to be used for UWB by FCC especially and communicates by letter and support that on this basis, estimating will have millions of systems based on UWB to come into operation in the recent period.

Largely, it is at the low data-rate applications with low pulse repetition rate that the UWB of prior art realizes, wherein can make pulse amplitude and interpulse spacing become big.This has brought the benefit of the UWB that usually quotes, that is, and and to resisting of the interference such as multipath disturbs.Yet, the higher data rate of application requirements in the future, promptly between the 100Mbs-500Mb/s scope, the routine techniques that is used for such system needs high pulse repetition rates, disturbs thereby reduce the distance between the continuous impulse and make the UWB system tend to multipath.

Summary of the invention

Therefore, needing a kind of cost effective method that is used for high data rate UWB communication system to eliminate multipath disturbs.System and method of the present invention provides a kind of like this UWB communication system, and this UWB communication system is used the multiband method, and wherein the span of each frequency band is approximately equal.

In each frequency band of the present invention, modulation scheme makes data rate can adapt to sub-band channel conditions flexibly.In each frequency band, service time, amplitude and phase modulated.In addition, utilize pseudo-random frequency sequence to provide enough multi-user interference to reduce.

Description of drawings

Fig. 1 a has illustrated the wireless network of communication station, and communication station only communicates by peer-to-peer communications;

Fig. 1 b has illustrated the wireless network of being set up and being controlled by the control point, and communication station is by control point and communication on the basis of reciprocity therein;

Fig. 2 a is the simplified block diagram of the structure of exemplary UWB communication station, has illustrated and will use the transmitter section of embodiments of the invention therein;

Fig. 2 b is the simplified block diagram of the structure of exemplary UWB communication station, and the receiver section that will use embodiments of the invention has been described;

Fig. 3 has illustrated multiband character position UWB modulation scheme;

Fig. 4 a-b has illustrated the frequency domain representation of multiband method; With

Fig. 5 has illustrated the simulation result of 5 frequency band 120Mb/s data rate UWB systems (8MHz symbol rate).

Embodiment

In the following description, in order to explain rather than, to have illustrated the detail such as particular communication station architecture, wireless network topology and interface, simulation result or the like, so that complete understanding of the present invention is provided in order to limit.Yet, very obvious for the person of ordinary skill of the art, can in other embodiment that breaks away from these details, put into practice the present invention.

Fig. 1 a has illustrated representative wireless ad-hoc (ad-hoc) the UWB piconet (pico-net) that will use embodiments of the invention.As shown in Figure 1a, 100 of dissimilar communication units communicate on the basis of reciprocity by Radio Link 110.Fig. 1 b has illustrated the representative wireless UWB network that also can use the embodiment of the invention.Shown in Fig. 1 b, the dissimilar communication unit 100 of piconet not only communicates by Radio Link 110 on the basis of reciprocity, also by Radio Link 120 go to/from the control point 130 of setting up piconet at first.Key principle of the present invention provides a kind of mechanism, and by this mechanism, when two types UWB piconet of communication unit 100 was near each other, they interfered with each other minimum.

Referring now to the transmitter subsystem (235) of Fig. 2 a,, the wireless communication unit 100 of one of UWB piconet of Fig. 1 a-b can comprise transmitter subsystem (235), and it has the structure shown in the block diagram of Fig. 2 a, and embodiments of the invention will apply to wherein.Shown in Fig. 2 a, communication unit can comprise information source 200, modulator 220, output stage 230 or transmitter, controller 240, time base 250, antenna 260 and the pseudo-random noise source 270 of cycle timing signal are provided.Controller 240 detects information signal, then according to definite time, amplitude and the phase modulated that will use of sub-band channel conditions, and to the determined modulation of modulator 220 indications.The example system of Fig. 2 a is for illustrative purposes.UWB output stage 230 is coupled to antenna 260, to launch desired data by propagation medium 231.The example system of Fig. 2 a is for illustrative purposes, and described antenna can be cable or for example be the integrated circuit that is configured to antenna.

Referring now to the receiver subsystem (295) of Fig. 2 b, the wireless communication unit 100 of the UWB piconet of Fig. 1 a-b can comprise receiver subsystem (295), and it has the receiver structure shown in the block diagram of Fig. 2 b, and embodiments of the invention will apply to wherein.Shown in Fig. 2 b, exemplary UWB communication unit can comprise demodulator 280, receiver 290, controller 240, time base 250, antenna 260 and the pseudo-random noise source 270 of cyclic timing signal are provided.Antenna 260 is shown is coupled to receiver 290, so that receive impact (impulse) radio signal of being propagated, but other execution mode also is possible, for example replaces antenna with cable and is used as propagation medium.Controller 240 detects the reception of 290 pairs of signals of being launched of receiver, determines employed time, amplitude and phase modulated according to sub-band channel conditions then, and indicates determined modulation to demodulator.The demonstration system of Fig. 2 b just for illustrative purposes.

Though illustrate to relate to normally used term in describing the particular transceiver system, be equally applicable to comprise other treatment system that has with the system of the structure inequality of structure shown in Fig. 2 a-b in the description of this proposition and notion.In addition, the piconet that illustrates in Fig. 1 a-b can have the communication unit of more participation piconets usually, just for convenience of description, has just simplified illustrated scale.

Suppose that the UWB channel is divided into N frequency band, and pulse shape h (t, 1), 1=1...N is used to each frequency band.So, the output of the wireless output stage 230 of UWB can be described by following formula:

$y\left(t\right)=\underset{n}{\mathrm{\Σ}}{a}_n{h}_l(t-\mathrm{nT}-c_n\mathrm{\τ},f\left(n\right))+b_n{h}_l(t-\mathrm{nT}-c_n\mathrm{\τ}-d_n{\mathrm{\τ}}_{\mathrm{ch}},f\left(n\right))---\left(1.1\right)$

Wherein

a _nAnd b _nBe amplitude or phase modulation data,

c _nAnd d _nBe difference time modulating data,

F (n) is a band component,

τ _ChBe for the channelizing purpose hour between unit, or be used for transporting the additional channel of data,

τ be used for position modulation hour between unit and

T is interpulse interval.

First embodiment illustrated in fig. 3 provide time/phase modulated pulse train.Each pulse is all by specific band transmission.For example, first pulse is preferably by 3.2-3.7GHz frequency band (500MHz bandwidth) carrying, and succeeding impulse is preferably launched in all the other frequency bands.In the preferred embodiment of Fig. 3 explanation, by UWB output stage or two subpulses of transmitter 230 each every band transmission.In the embodiment that replaces, UWB output stage or transmitter 230 each every frequency bands are only launched a subpulse, are about to a in the above-mentioned formula (1.1) _nOr b _nBe arranged to 0.

In a further advantageous embodiment, Fig. 4 a-c shows the frequency domain representation of the multiband transmission of UWB pulse.Fig. 4 a has illustrated the single band transmission, and Fig. 4 b has illustrated 3 frequency band transmission, and Fig. 4 c illustrated 6 frequency band transmission, has wherein skipped a frequency band of 400 between the centre.In time domain, multiband transmission in time-multiplexed mode so that the maximized method in interpulse interval (T) carry out.Present embodiment allows to realize with receiver better and that cost is lower.

Advantage of the present invention is the flexibility of resource the transmission quality of compromise in bandwidth, data rate, realization complexity and each frequency band.In a preferred embodiment, frequency band carrying 20Mb/s data, and another frequency band carrying 30Mb/s data.The data rate allocation of each frequency band is according to the needs of using and according to subchannel capacities.

In order to further specify this flexibility, table 1 has been listed the embodiment of combination of resources.First row show 1 frequency band UWB system of carrying 20Mb/s payload.It uses 10Ms/s chip rate and each code element carrying 2 Bit data, and one is passed through amplitude/phase, and another passes through the position.Secondary series shows the 110Mb/s system that uses 5 frequency bands.Chip rate is maintained at 10Ms/s.30 bits of every transmission of symbols (each channel 3 bits/sym, wherein 1 bit is with phase place, 2 bits are with the position).Other row also illustrate corresponding preferred embodiment.

In a preferred embodiment, can adjust the bit rate of each tired band easily according to the requirement of channel condition and application.For example, in a preferred embodiment, a frequency band can carry 2 bits/sym, and another frequency band carries 4 bits/sym.

Table 1: the resource distribution of given data rate

Data rate	20Mb/s	110Mb/s	200Mb/s	480Mb/s
					Frequency band number	1	5	6	8

Modulation	1(DPSK)+1(SPM )	1(DPSK)+2(S PM)	2(BPSK)+2( SPM)	2(BPSK)+4( SPM)
					Chip rate/frequency band	10Ms/s	10Ms/s	10Ms/s	20Ms/s
Original bit speed	20Mb/s	150Mb/s	240Mb/s	640Mb/s
					Symbol interval	100ns	100ns	100ns	50ns
T	100ns	20ns	16ns	6.5ns

Embodiment in the table 1 illustrates that every frequency band hangs down symbol rate system.Low symbol rate system like this makes it possible to design the transceiver system that anti-multipath disturbs.

Unrestricted for example, Fig. 5 marks out the simulation result of 5 frequency band 120Mb/s UWB systems in the drawings.The position part is carried every band/symbol 2 bits, and amplitude is partly carried every band/symbol 1 bit.The time stride of position part is 2.5ns.The bandwidth of each pulse is near 500MHz.As shown, the position partial properties is more a bit weaker than amplitude partial properties.

The present invention can realize with other particular form, and do not break away from its spirit and essential feature.The embodiment that is provided is for the purpose of illustration only and without any limited significance.Scope of the present invention is by the indication of appended claim, rather than by aforementioned description indication, and therefore all modifications of making in the implication of the equivalent of claim and scope is included among the scope of the present invention.

Claims (15)

1. method of using super-broadband tech to transmit data said method comprising the steps of:

(a) provide transmitter subsystem, it is configured to execution in step

(a.1) provide the UWB channel as a series of UWB signal pulses,

(a.2) the UWB channel distribution is become N frequency band,

(a.3) by each pulse in the described series of one of described N frequency band of being divided transmission; And

(a.5) transmit with the time division multiplexing mode carrying so that the maximization of interpulse spacing;

(b) provide receiver subsystem, it is configured to execution in step

(b.1) receive the UWB signal that is divided into N frequency band,

(b.2) N combinations of bands become the UWB channel and

(b.3) obtain a series of UWB pulses from N the frequency band that is made up.

2. the described method of claim 1, wherein said partiting step (a.2) comprise that further (a.2.1) divide described UWB channel so that the step that the span of each frequency band approximately equates.

3. the described method of claim 1 comprises that further (a.4) use at least a modulation technique to modulate the step of described serial UWB pulse, and described modulation technique is to select from the group that comprises time/phase place, frequency and amplitude.

4. the step that (a.4.1) utilizes the pseudo noise frequency sequence to provide enough multi-user interference to reduce further is provided for the described method of claim 3, wherein said modulation step (a.4).

5. the described method of claim 3, wherein said forwarding step (a.3) further comprises step:

(a.3.1) send first pulse of the series that is provided by the 3.2-3.7GHz frequency band of a described N frequency band; With

(a.3.2) any pulse of transmission except that first pulse of described series in non-first frequency band of a described N frequency band.

6. the described method of claim 1, wherein in N＞3 o'clock, described forwarding step (a.3) comprises further that selectively (a.3.3) skip the step of at least one intermediate frequency band in the described N frequency band.

7. the described method of claim 1 further comprises step when N=2:

(a.6) by first frequency band carrying 20Mb/s; With

(a.7) by second frequency band carrying 30Mb/s.

8. the described method of claim 1 comprises that further (a.8) distribute the step of the data rate of every frequency band according in application demand and the subchannel capacities at least one.

9. the method for claim 8 further comprises step:

(a.9) first frequency band by a described N frequency band carries 2 bits of every code element;

(a.10) second frequency band by a described N frequency band carries 4 bits of every code element.

10. the described method of claim 8, further comprise (a.11) step according to the application demand Resources allocation, wherein said resource is at least one among number of frequency bands, modulation, chip rate/frequency band, original bit rate, symbol interval and the interpulse spacing.

11. the described method of claim 10 comprises that further (a.12) distribute the step of the every code element n bit of each channel, wherein by position carry m bit and by amplitude/phase carrying n-m bit.

12. a device that is used for multi-band ultra-wideband (UWB) communication system comprises:

Transmitter subsystem comprises

Controller is configured to the UWB channel distribution is become N frequency band,

Modulator is configured to provide modulated pulse trains,

Transmitter is configured to send each modulating pulse by one of described N frequency band, and described transmission carries out in time-multiplexed mode so that interpulse spacing T maximization; With

Receiver subsystem comprises

Receiver is configured to receive the UWB signal that sends by described N frequency band,

Controller, be configured to the synthetic modulated pulse trains of paid-in sets of signals and

Demodulator is configured to the demodulation modulated pulse trains.

13. the described device of claim 12, wherein:

Described transmitter also comprises the device of selecting that is used to send from the group of being made of the integrated circuit (IC) of antenna, cable and enforcement antenna function; And

Described receiver also comprises the device of selecting that is used to receive from the group of being made of the integrated circuit (IC) of antenna, cable and enforcement antenna function.

14. the described device of claim 12, the span of each frequency band in the wherein said N frequency band is approximately equal.

15. the described device of claim 12 also comprises:

To the pseudo-random frequency sequence input of described modulator,, enough multi-user interference reduce so that being provided.

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