MXPA97002849A - Method and apparatus for switching spread spectrum/code division multiple access modulated beams - Google Patents

Abstract

Switching of traffic channels within spread spectrum beams is performed in a satellite without buffering of the individual signals. Individual satellite beams carrying spread spectrum user RF signals form a plurality of customer premise equipments are received by radio receivers of a satellite switch and downconverted to IF signals. Traffic channel recovery is performed immediately after the down conversion and digital encoding and decoding is performed to route each channel to an appropriate outbound satellite beam. Traffic channel recovery is by despreading and filtering followed by respreading to uniquely identify each user signal so it may be recovered at its end destination. Further spreading uniquely identifies the user signal with an outbout satellite beam going to the intended destination of the user signal.

Description

METHOD AND APPARATUS FOR SWITCHING MODULATED MACHINES FOR MULTIPLE ACCESS WITH DB DIVISION CODE / SPECTRUM ROPACJnnq Field of the Invention This invention relates to apparatus and switching methods for use in wireless digital telecommunications systems and / or wired for message switching. It deals particularly with the switching of spread-spectrum / CDMA-modulated beams, which transport traffic channels from a specific source to a specific destination. Background of the Invention The digital switching of CDMA digital telecommunications signals / propagated spectrum has previously been limited to Circuit and packet switching. Packet-type switching is signaling with batch transmission and generally requires the use of a buffer somewhere in the transmission process. The switching (ie, completion of CDMA messages) of end-to-end CDMA complete message signals without buffering has been considered to have sufficient complexity to make it impractical and not economical. In some instances, a CDMA beam may be redirected but the individual traffic channels included within each uplink beam remain undisturbed in a corresponding downlink CDMA beam. The uplink CDMA beams are re-directed and converted into a downlink beam, but REF: 24056 includes the same traffic channels. Thus, the traffic channels must have common destinations with the common re-directed CDMA beams in which they are included. In some cases, the handling of CDMA packet beams requires the conversion of CDMA traffic channels to baseband frequencies, for the switching and re-addressing processes to occur. SUMMARY OF THE INVENTION Therefore, according to the invention, a method and apparatus for switching traffic channels between CDMA modulated beams / uplink and downlink propagated spectrum is disclosed and claimed in the claims. In particular, it deals with traffic channel switching with CDMA information (ie message) where a signal of aggregate aggregate information is switched to JF frequency without buffer processing required in the process. In a particular embodiment of the invention, bundles of individual satellites carrying RF user signals of propagated spectrum in a plurality of customer facility equipment, receivers of a satellite switch are received by radio and converted into downstream signals to IF signals. The traffic channel recovery is performed immediately after the downward conversion and digital coding coding is performed to direct each channel to an appropriate satellite output beam.

The traffic channel recovery is by depropagation and filtering followed by repropagation to uniquely identify each user signal, so that it can be recovered at its final destination. Greater propagation only identifies the user signal with an output satellite beam, which passes to the intended destination of the usage signal. Brief Description of the Pippet Figure 1 is a block schematic of a code switching system architecture; Figure 2 is a block schematic of a switch with code address; Figure 3 is a schematic of "blocks of a traffic channel recovery circuit that is a subcomponent of the code address switch;" Figure 4 is a schematic of the array assembly for directing traffic channels to the CDMA beam of output addressed to the appropriate destination Detailed Description A code switching architecture as illustrated in Figure 1 includes a control unit 101 having memory storage for uplink sources relating to traffic matrix for downlink destinations The ascending link channels 103, which may comprise a plurality of CDMA access and ascending data beams 1 through N, they are directed to an access channel reception unit 105 for processing and for which the output is directed to the control unit 101. The output of the control unit 101 is applied to a satellite broadcast transmission unit 107, in where it supplies the access channels and downlink broadcast data on the CDMA beams 109. A second output of the control unit is applied, by the terminal 111 to a switch with code division 125. The switch with code division 125 it accepts a plurality of modulated RF beams of CDMA bearers 131, extracts the individual traffic channels contained within each beam and combines them into output beams having a common destination with the traffic channels it contains. The destination traffic channels are inserted into downlink CDMA beams 133, according to broadcast channels applied to CDMA multiplexers 132-1 to 132-N, for transmission to specific downlink destinations. While a satellite application using the air interface is shown as an illustrative embodiment, the invention is not limited to satellite communications systems. The invention is equally applicable to terrestrial communications systems and systems using optical and wired connections.

In Figure 2, a plurality of wide-spectrum RF input beams 201-1 to 201-N, all apply to downconversion units 202-1 to 202-N that convert the beams to IF. The downlinked IF beams 203-1 to 203-N are propagated with a pseudo-random beam code gn applied to the mixed circuits 204-1 to 204-N to identify the individual traffic channels. In the exemplary embodiment gn may be a Gold code with slight interference between adjacent satellite beams. The coded signals of each mixer are applied to ducts 205-1 to 205-N that are coupled to various traffic channel recovery circuits 206-1-1 to 206-1-1 to 2? É-Nl to 206 -Nl. The individual traffic channels are retrieved from each of the IF beams by despreading and repropagation techniques as described with respect to Figure 3. The output of all the circuits for recovery of traffic channel are summed together in the summer 207 and they apply in common to the overpropagation duct 208 that transports the overpropagation signals from the traffic channel recovery circuits 206-1-1 to 206-1-L to 206-Nl to 206-NL, to the 209-1 mixers up to 209-N. The outputs of the overpropagation beams of the duct 208 are recovered by depropagation with a Walsh code W, in the mixers 209-1 to 209-N to avoid translapping the adjacent satellite beams. By integrating (ie, analog or accumulating) (i.e., digital) the beam propagated in integrators 210-1 to 210-N to recover the signal over the code length in order to generate the spread spectrum beams of output 211-1 to 211-N that has destinations in harmony with the channels they contain. A circuit for recovery of convenient traffic channels illustrated in Figure 3 accepts the output of one of the ducts 205-N and applies it to a mixer 303 where the traffic channel, in the illustrative mode, is depropagated with a Walsh code W,, to prevent traffic channels from translating within a beam. This non-propagating traffic channel is integrated into the integrator 304 to reduce the sampling rate at the symbol rate. Subsequently, the integrated signal is filtered by the IF filter 306. If digitally performed, the filtering stage is incorporated in the depropagation operation. The filtered traffic channel is repropagated by a Walsh code of the output beam Wna in the mixer 307 for uniquely identifying the user, and in addition reproposing by a pseudo-random downlink beam code in the mixer 309 to identify the output beam carrying the traffic channel. The output of the mixer 309 is overpropagated with an octagonal Walsh code Wk in the mixer 311 to separate the output beams in the overpropagated duct. The output of the mixer 311 for application to the summing circuit is as illustrated in Figure 1.

A matrix is used in the illustrative mode to couple traffic channels of a CDMA beam to a beam CDMA output. An illustrative matrix (for three beams) that can be used in the control unit to direct uplink traffic channels in downlink beams is illustrated in Figure 4 and can be contained in the control unit as part of a program stored. As illustrated, the columns are identified with the downlink CDMA beams and the rows are identified with the uplink CDMA beams. Each uplink and downlink CDMA contains a plurality of user traffic input channels U "+ U» + + Up and output U.

+ Ub + + Uto, respectively. The matrix entries indicate the codes to be used for the uplink and downlink traffic channels. This ensures that the downlink traffic channels are included in the desired downlink beam. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (12)

1. CLAIMS 1.- Method for switching a channel from a broad spectrum beam to a spread spectrum spectrum, comprising the steps of: coding each channel in the incoming spectrum beam, in a way to improve channel separation and reduce interference between individual channels contained within the beams and recover individual traffic channels by application of a user-specific pseudo-random beam code; characterized by: adding up all recovered traffic channels in an overpropagated pipeline; direct and combine the individual traffic channels recovered from the pipeline in outbound propagated spectrum beams, which have a common destiny with the traffic channels they contain.
2. 2. A method for switching a channel from a beam of spread spectrum of input to a beam of spread spectrum output as described in claim 1: characterized in that the step of coding each channel includes overpropagate with application of an overpropagation code .
3. 3. A method for switching a channel from a beam of spread spectrum of input to a beam of spread spectrum output as described in claim 1: characterized in that the step of coding each channel includes filtering IF of the traffic channel during recovery of traffic channel.
4. 4. - A method for switching a channel from a beam of spread spectrum of input to a beam of spread spectrum output as described in claim a, characterized in that the stage of directing and combining includes a step of mixing with a Walsh code and add the mixed signal for a codeword length.
5. 5. A method for switching a channel from a beam of spread spectrum of entry to a beam of spread spectrum output as described in claim 4: characterized in that the step of combining a step of recovering individual output beams by application of the code dispropagation in a fourth mixer.
6. 6.- A switching system for switching a channel from a beam of propagated spectrum of input to a beam of propagated output spectrum, comprising: circuits, for frequency conversion connected to RF beams of propagated propagating spectrum and to convert them into you do IF; characterized by: mixing circuits for dispropagation of the IF beams as a pseudorandom beam code; a plurality of circuits for traffic channel recovery connected to receive the propagated IF beams and operating to recover individual traffic channels; and the traffic channel recovery circuit includes: a plurality of destination selection mixers, each connected to receive the output of the traffic channel recovery circuit and apply an overpropagation code to the traffic channels; means for forming propagated output spectrum beams that have a common destination with the traffic channels contained therein.
7. 7. a switching system for switching a channel from a beam of spread spectrum of entry to a beam of spread spectrum output as described in claim 6, characterized in that it comprises: the plurality of destination mixers includes: a first mixer destination selection to identify the user within the destination beam; and a second mixer for destination selection, to identify the output beam and its destination.
8. 8. A switching system for switching a channel from a spectrum of incoming propagated spectrum to a beam of propagated output spectrum as described in claim 6, characterized in that it comprises: that the circuit for recovery of traffic channel also includes : a third mixer for overpropagation of outgoing traffic channels.
9. 9. A switching system for switching a channel from a beam of propagated spectrum of entry to a beam of propagated output spectrum as described in claim 6, characterized in that it comprises: wherein the output beam is mixed in a quarter mixer with an orthogonal code and process by an integradsr to recover the output channel by the length of an overpropagation code.
10. 10.- Switching system to switch in the sky a channel of an RF beam of propagated spectrum of entry to an RF beam of propagated spectrum of output, characterized by: circuits for frequency conversion connected to receive RF beams of income propagated spectrum and to convert them in descending form in IF beams; means for applying a pseudo-random beam code gn to identify individual channels; a plurality of circuits for traffic channel recovery connected to receive a plurality of propagated IF beams and furthermore to depropagate and propagate by an orthogonal code which retrieves identities of individual traffic channels; the circuit for recovery of traffic channel includes: circuits for depropagation of IF beams with the orthogonal code to avoid trahslapping of channels within a -vS ?? "P make circuits to integrate the IF dep / garbed beams to recover a symbol speed, circuits of repropagation of the IF beam with the orthogonal code to uniquely identify channel users, and circuits for repropagation of the beam IF for a pseudorandom beam code to identify the output beam code that transports the channel to its destination.
11. 11.- switching system for switching in the sky a channel from an RF beam of propagated transmission spectrum to an RF beam of propagated output spectrum as described in claim 10, characterized in that it also comprises: circuits for overpropagation of the beam output to separate different output beams.
12. 12.- Switching system for switching in the sky a channel of an RF beam of propagated spectrum of input to an RF beam of propagated output spectrum as described in claim 10, characterized in that it also comprises: means for applying include a mixer circuit for depropagation IF beams with the pseudo-random beam code g ".