WO2002003660A2

WO2002003660A2 - Method and apparatus using synchronization burst designs for multiple radiotelephone environments

Info

Publication number: WO2002003660A2
Application number: PCT/US2001/020314
Authority: WO
Inventors: Ram S. Swamy
Original assignee: Motorola Inc.
Priority date: 2000-06-30
Filing date: 2001-06-26
Publication date: 2002-01-10
Also published as: AU2001270175A1; WO2002003660A3

Abstract

A method and device for discriminating between an EDGE COMPACT mode and a GSM/EDGE CLASSIC mode in a radiotelephone transmission received by a radiotelephone device are provided. The method comprises the steps of receiving a synchronization burst (601) in the radiotelephone transmission and correlating (607) the synchronization burst to an ETS code contained within the radiotelephone device. The ETS code is either an EDGE COMPACT ETS code or a GSM/EDGE CLASSIC ETS code. The method continues reception (615) of the radiotelephone transmission if the synchronization burst substantially correlates to the ETS code. The EDGE COMPACT ETS code is substantially orthogonal to the GSM/EDGE CLASSIC ETS code.

Description

METHOD AND APPARATUS USING SYNCHRONIZATION BURST DESIGNS FOR MULTIPLE RADIOTELEPHONE ENVIRONMENTS

BACKGROUND OF THE INVENTION

This invention relates to synchronization of mobile radiotelephones in a cellular, digital mobile radiotelephone system, and more particularly to synchronization of mobile 10 radiotelephones operating under GSM/EDGE COMPACT and EDGE CLASSIC modes.

Fig. 1 is a diagrammatic representation of a radiotelephone system, such as a cellular telephone system, containing multiple cells and co responding base stations serving the cells. The base stations and mobile stations may operate according to a GSM, a GPRS-136HS EDGE COMPACT, or an EDGE CLASSIC mode of operation. Alternatively, they could be 15 equipped to operate according to all three modes of operation.

One type of digital mobile telephone system employed in a cellular mobile communications network is generically designated by the acronym GSM, which is an abbreviation for the "mobile special group" (Groupe Speciale Mobile, in French). The GSM system is standardized under ETSI (European Telecommunications Standards Institute). In 20 this system the radio transmission is purely digital TDMA (Time Domain Multiple Access). In January of 1998, the EDGE standard (Enhanced Datarate for GSM Evolution, also later called as Enhanced Datarate for Global Evolution) was adopted as a key part of a high speed data evolution. The EDGE standard is defined by the standards committee called TIA TR45.3 of the Telecommunications Industry Association. A general description of the 25 EDGE system architecture and protocols are provided in the TR45.3 TDMA Third- Generation Wireless document called "EGPRS-136 (Enhanced General Packet Radio Service) Overview", TIA/EIA- 136-370 of the Telecommunications Industry Association, to be published as a TIA/EIA standard, and incorporated herein by reference.

The EDGE system has evolved into an EDGE COMPACT proposal that 3 o advantageously utilizes a reduced bandwidth. The EDGE COMPACT standard utilizes synchronized base stations and time-multiplexed control channels to achieve a minimum spectrum deployment of 0.8 MHz. The EDGE COMPACT proposal is described in Concept Proposal for GPRS-136HS EDGE, Rev. 1.4, by UWCC Tdoc SMG2 EDGE 322/99, ETSI SMG2 Working Session on EDGE August 24-27, 1999, Paris, France, incorporated herein by reference. The EDGE COMPACT proposal is also described in Concept Proposal for GPRS- 136HS EDGE, Rev. 1.0, UWCC Tdoc SMG2 530/99, ETSI STC SMG2 Meeting May 31 - June 4, 1999, Tucson, AZ, USA, incorporated herein by reference.

For radiotelephone systems that are not facing spectrum limitations, the GSM Community also supports the development of ETSI-EDGE, referred to as EDGE CLASSIC, requiring 2.4 MHz of initial spectrum. For purposes of synchronization of a mobile station, discussed below, GSM, EDGE, EDGE CLASSIC, and other variants function similarly and are hereinafter referred to as GSM/EDGE CLASSIC. EDGE COMPACT is desired to synchronize differently, and is referred to herein as EDGE COMPACT.

A GSM/EDGE CLASSIC radiotelephone system includes traffic channels (TCHs) and control channels. The control channel includes a frequency correction channel (FCCH) for frequency correction of a mobile station, a synchronization channel (SCH) for frame synchronization of the mobile station and identification of a base transceiver station, and a broadcast control channel (BCCH) for general information from a base station. The COMPACT synchronization channel is called CSCH, and the COMPACT frequency correction channel is called CFCCH.

A base station sends signals on the broadcast control channel to enable a mobile station to synchronize itself to the base station, and, if necessary, to correct its frequency standard so as to put it in line with the frequency of the base station. The signals sent by the base station for these purposes are a frequency correction burst (FB) and a synchronization burst (SB, also called synch burst). The synchronization requirements are described in GSM recommendation 05.10, Radio Sub-System Synchronization, Version 3.4.0, published March 1990, available from the European Telecommunications Standards Institute (ETSI), and incorporated herein by reference. A burst is defined as an interval within which a predetermined data stream modulates the radio frequency carrier (i.e., a predetermined bit sequence). The synchronization burst begins with three tail bits, followed by 39 encrypted bits and then 64 bits of Extended Training Sequence (ETS) code, followed by another 39 encrypted bits, three tail bits and a guard interval. The extended training sequence code is a predetermined pattern of ones and zeroes, comprising a pseudorandom sequence.

FIG. 2 is a representation of the data structure of a TDMA frame. The TDMA frame 201 contains eight time slots. Encoded bursts transmitted from a base station may include a Normal Burst (NB) 202, a Frequency Correction Burst (FB) 203, a Synchronization Burst (SB) 204, a Dummy Burst (DB) 205, and an Access Burst 206.

During generation of a synchronization burst, a base station may select a GSM/EDGE CLASSIC (SCH 415) channel or an EDGE COMPACT (CSCH 416) type of channel to be used for transmission. Correspondingly, the ETS code 208 of the synchronization burst 204 is used for frame synchronization in a receiving mobile station. The prior art coding bit sequence of the ETS code (418) for the GSMEDGE

CLASSIC synchronization channel (SCH) is (BN42, BN43 - BN105)=(1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1).

The received ETS code may be auto-correlated against a pre-stored bit sequence in the receiving radiotelephone device. The auto-correlation function generates a correlation strength output as a result of a comparison between an incoming synchronization burst and the pre-stored bit sequence. If they strongly correlate, the mode of the received radiotelephone signal matches the mode of the receiving radiotelephone device. If they do not strongly correlate, the receiving radiotelephone device can determine that the received synchronization burst does not match the pre-stored bit sequence.

In the past, both the GSM/EDGE CLASSIC and EDGE COMPACT modes employed the same ETS code that was originally specified for GSM synchronization bursts. This resulted in no discrimination between GSM/EDGE CLASSIC and EDGE COMPACT modes during frame synchronization. Thus, base station transmissions intended exclusively for COMPACT packet data service could interfere in GSM/CLASSIC specific phones and channels through an unwanted and/or improper synchronization. In other words, the COMPACT synchronization burst is not transparent to the SCH of both CLASSIC and GSM receiving channels, and vice versa. FIG. 3 illustrates a prior art GSM/EDGE CLASSIC mobile station 3. The prior art mobile station 3 may include a burst processor 306 that includes timing counters 308, a synchronization channel processor.307, control circuits 310, and the ETS code 309.

In the prior art, the ETS code 309 contains only the GSM/EDGE CLASSIC bit sequence, and uses the synchronization channel processor 307 to correlate a received synchronization burst against a stored GSM/EDGE CLASSIC ETS code 309. Therefore, the prior art mobile station 3 is unable to properly discriminate between GSM/EDGE CLASSIC and EDGE COMPACT modes, since the ETS code bit sequence is the same for both modes.

Therefore, there is a potential problem for all existing GSM phones arising from COMPACT synchronization burst transmissions not intended for them. A GSM/EDGE CLASSIC specific phone can improperly attempt to synchronize to an EDGE COMPACT synchronization burst. A similar problem exists in EDGE COMPACT phones attempting to synchronize to a GSM/EDGE CLASSIC transmission. In addition, an improper synchronization may waste battery power of a mobile phone.

What is needed, therefore, is a method and apparatus for uniquely synchronizing a mobile radiotelephone in GSM/EDGE CLASSIC and EDGE COMPACT cellular networks.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features and advantages of the present invention will become more evident by an association of the prior art with the enhancement provided by the detailed description of the invention together with the accompanying drawings. FIG. 1 depicts a typical cellular radio system; FIG. 2 is a representation of the data structure of a TDMA frame; FIG. 3 illustrates a prior art mobile station; FIG. 4 shows an exemplary base station according to an embodiment of the present invention;

FIG. 5 shows an exemplary mobile station according to an embodiment of the present invention; FIG. 6 shows a flowchart illustrating a method of discrimination of a first embodiment of the present invention; and

FIG. 7 shows a flowchart illustrating a method of discrimination of a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order to address drawbacks in the prior art, the present invention describes a method and apparatus for ensuring that frame synchronization in an EDGE COMPACT mobile station is transparent to a GSM or an EDGE CLASSIC transmission. Similarly, the invention also ensures that frame synchronization in a GSM or EDGE CLASSIC mobile station is transparent to an EDGE COMPACT transmission. The method and apparatus of the present invention allow a mobile station to discriminate between different types of synchronization bursts and therefore synchronize only to an intended mode.

The coding bit sequence of the COMPACT extended training sequence of CSCH in one embodiment of the present invention comprises (1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0,

0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0). In an alternate embodiment, the bit sequence comprises (1, 1, 0,

1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1). Either of the above sequences may be used to replace the prior art GSM/EDGE

COMPACT ETS code in order to enable a reliable differentiation between modes and synchronization of a received radio transmission. The bit sequence of the present invention was presented and has been accepted in the EDGE COMPACT radiotelephone standard, as described in Recommendation GSM 05.02, Multiplexing and Multiple Access on the Radio Path, Version 8.2.0, ETSI, 1999, incorporated herein by reference.

The bit sequence of the EDGE COMPACT ETS code of the present invention is substantially orthogonal to the bit sequence of the GSM/EDGE CLASSIC ETS code. Therefore, a cross-correlation of a received GSM EDGE CLASSIC synchronization burst against a pre-stored EDGE COMPACT ETS code produces a minimal correlation number so it appears to be transparent and is not recognized. A normalized correlation number typically ranges from zero (no correlation) to one (maximum correlation). Therefore, by employing an EDGE COMPACT bit sequence of the present invention, a radiotelephone device can distinguish between GSM/EDGE CLASSIC and EDGE COMPACT modes by recognizing their respective bit sequences.

A correlation may be performed using a Binary Pattern Correlator or Digital Matched Filter/Correlator IC chips. Representative correlators are discussed below in conjunction with FIG. 5. Therefore, according to the present invention, a SCH mode message can be made to be transparent to a COMPACT mobile, and a CSCH mode message can be made to be transparent to a GSM/EDGE CLASSIC mobile.

FIG. 4 shows an exemplary base station 4 according to an embodiment of the present invention. The base station 4 includes a burst generator 407 that includes a GSM/EDGE CLASSIC ETS code 418 for the SCH 415 as in the prior art and an EDGE COMPACT ETS code 419 for the CSCH 416 according to an embodiment of the present invention. The codes enable the base station 4 to transmit in GSM/EDGE CLASSIC and/or EDGE COMPACT modes, with the transmitted modes capable of being discriminated between by a receiving mobile station through automatic synchronization. The discrimination is enabled by the EDGE COMPACT bit sequence of the present invention. The base station 4 may also include an antenna 405, a CPU 410, a memory, such as for example a Read Only Memory (ROM) (for storing ETS codes), a radio transmitter 408, a trunk circuit 406, a frequency source 414, a timing generator 411, a control station 409, a delay adjustment circuit 412, a base station synchronization unit 413, an A/D converter 401, a speech or data encoder 402, a channel coder 403, and an interleaver 404. The burst generator 407 further includes control circuits 417 in addition to the GSM/EDGE CLASSIC ETS code 418 and the EDGE COMPACT ETS code 419.

The burst generator 407 produces data bursts, including the frequency and synchronization bursts. For example, the burst generator 407 may produce a synchronization burst as defined and specified in GSM 05.02 and depicted in FIG. 2. The burst generator 407 can produce a GSM/EDGE CLASSIC synchronization burst using the stored GSM/EDGE CLASSIC ETS code 418. In addition the burst generator 407 can produce an EDGE COMPACT synchronization burst using the stored EDGE COMPACT ETS code 419.

Each cell of FIG. 1 is served by a base station 4, called a base transceiver station (BTS) in GSM terminology.

The CPU 410 selects the ETS codes and executes all stored program instructions. The CPU 410 is responsible for the overall control of the base station 4, and controls the other units in the base station 4 in accordance with program instructions stored in memory and in accordance with the control circuits 417. The CPU 410, the timing generator 411, and the control circuits 417 select at least one of the time slots comprising the dedicated physical channel.

The transmitter 408, the CPU 410, and the frequency source 414 select the radio frequency to be used for transmission of a Broadcast Control Channel (BCCH) or Compact Packet Broadcast Control Channel (CPBCCH) carrier. This may be done, for example, according to GSM standards.

The radio transmitter 408 converts the baseband signal received from the burst generator 407 into a radio signal by modulating a radio frequency carrier wave as determined by the frequency source 414. The radio transmitter 408 also amplifies it to a suitable power level for radiation through the antenna 405. The control station 409 is connected to a public switched telephone network (PSTN) and to the base station trunk circuit 406. The control station 409 controls communications with telephone landlines.

The A/D converter 401, the speech or data encoder 402, the channel coder 403, and the interleaver 404 are subunits that may be included in the base station. The CPU 410, together with the connection to delay adjustment circuit 412, adjusts for time delays.

The timing generator 411 is connected to abase station synchronization unit 413, whereby a plurality of radio base stations are synchronized with respect to TDMA frames. This may preferably be done in accordance with GSM standards, and more preferably in accordance with the GSM 05.10 standard.

It should be understood that the base station 4 is provided for illustration, and may be alternatively constructed of other components and function differently that the embodiment shown. The inclusion of an EDGE COMPACT ETS code as in the present invention applies to any manner of base station.

FIG. 5 illustrates an exemplary mobile station 5 according to an embodiment of the present invention. The mobile station 5 includes a burst processor 506. The burst processor 506 implements a correlator function that is used to correlate a received synchronization burst against a pre-stored bit sequence. The burst processor 506 further includes an EDGE COMPACT synchronization processor 507 and a stored GSM/EDGE COMPACT ETS code 509 according to the present invention. The new COMPACT extended training sequence code for the CSCH mode 419, 509 may be stored in a memory, such as, for example, a Read Only Memory (ROM). The memory is accessible to the CPU 515. The mobile station 5 may use the stored GSM/EDGE COMPACT ETS code 509 and the EDGE COMPACT synchronization processor 507 to compare (i.e., correlate) a received synchronization burst ETS code 419 to the stored EDGE COMPACT ETS code 509. If the comparison succeeds, the mobile station 5 synchronizes and receives in the EDGE COMPACT mode. Otherwise, if the mobile station 5 is designed for both modes, the mobile station 5 synchronizes and receives in the GSM EDGE CLASSIC mode. Various types of programmable digital correlators may be used for frame synchronization. Such correlators can be programmed specifically for any given ETS code. The auto-correlation procedure and hardware are described in Digital Communications, by John G. Proakis, McGraw-Hill, and also in Information Transmission, Modulation and Noise, by M. Schwartz, McGraw-Hill, both of which are incorporated herein by reference. Typical digital correlators are discussed in Digital Matched Filter/Correlator, STEL-3310 Stanford Communications, 1990, and in Binary Pattern Correlator Megafunction, Nova Engineering Solution Brief 18, Altera Corporation, April, 1997, ver. 1.0, incorporated herein by reference. The burst processor 506 further includes timing counters 508 and control circuits 510. 5 The mobile station 5 may also include an antenna 511, a signal level meter 512, a radio receiver 513, a CPU 515, a timing generator 516, a Compact Frequency Correction Channel (CFCCH) detector 517, a frequency source 518, a user data output 501, a data decoder 502, a channel decoder 503, a deinterleaver 504, an equalizer 505, and an A/D converter 514. o The antenna 511 is connected to the radio receiver 513 and passes radio frequency signals to the radio receiver 513.

The signal level meter 512 performs received signal strength measurements.

The radio receiver 513 converts the base station signal received by the antenna 511 to a baseband signal by demodulating the carrier. The baseband signal is then processed in the 5 burst processor 506. This may be done, for example, in accordance with GSM standards such as the GSM 05.04 and 05.02 standards.

The control circuits 510, the CPU 515, and the timing generator 516 may select at least one of the time slots comprising the dedicated physical channel.

The radio receiver 513, the CPU 515, the CFCCH detector 517, and the frequency o source 518 may select the received radio frequency COMPACT Packet Broadcast Control

Channel (CPBCCH) carriers transmitted by the base station on the selected frequency in the selected time slot.

The CFCCH detector 517 detects and decodes the COMPACT frequency correction channel (CFCCH) carried by the CPBCCH-carrier. This may be done, for example, in 5 accordance with GSM standards such as the GSM 05.02 standard.

The channel decoder 503, the deinterleaver 504, and the burst processor 506 decode, detect, process and synchronize the COMPACT synchronization channel (CSCH) carried by the CPBCCH-carrier. This may be done, for example, in accordance with GSM standards such as the GSM 05.02 standard, and more specifically in accordance with revision 8.2.0 of the GSM 05.02 standard.

The timing generator 516, the CPU 515, and the control circuits 510 work in unison to synchronize and control all timing operations of the mobile station 5. The timing counters 508 are a set of counters Rl, R2, TG used as a time reference in the mobile station. Details of the counters are given in Digital cellular telecommunications system (Phase 2+); Radio subsystem synchronization, GSM 05.10 version 8.1.0, Release 1999, incorporated herein by reference.

The A/D converter 514, the channel decoder 503, the equalizer 505, the deinterleaver 504, and the data decoder 502, are subunits that may be included in the mobile station.

It should be understood that the mobile station 5 is provided for illustration, and may be alternatively constructed of other components and function differently that the embodiment shown. The inclusion of an EDGE COMPACT ETS code as in the present invention applies to any manner of mobile station. A radiotelephone device according to the present invention includes a burst processor for generating and/or decoding a synchronization burst and a memory for storing an ETS code according to the present invention. The radiotelephone device includes a radio communications device capable of either broadcasting a transmission that includes an embedded EDGE COMPACT ETS code of the present invention, receiving a transmission that includes the EDGE COMPACT ETS code synchronization burst of the present invention, or both. The radiotelephone device of the present invention therefore includes a base station and a mobile station.

Fig. 6 shows a flowchart 600 illustrating the method of discrimination of a first embodiment of the present invention. In step 601, the radiotelephone device receives a transmission including a synchronization burst.

In step 607, the radiotelephone device correlates the received synchronization burst to a current mode. The current mode may be, for example, a GSM/EDGE CLASSIC or an EDGE COMPACT mode. The current mode of the radiotelephone device may be reflected in a pre-stored ETS code within the radiotelephone device. It should be noted that a radiotelephone device may operate under more than one mode and may store more than one ETS code, including the EDGE COMPACT ETS code according to the present invention.

In step 615, if the received synchronization burst substantially correlates to the pre- stored ETS code, the radiotelephone device continues to synchronize and receive in that mode. If the received synchronization burst did not substantially correlate, the radiotelephone device may discontinue synchronizing and receiving. In this manner, the radiotelephone device is capable of synchronizing to appropriate transmissions, and is capable of ignoring transmissions in different modes. Alternatively, if the received synchronization burst did not substantially correlate, the radiotelephone device may synchronize and receive in an alternate mode (i.e., if the pre-stored code is an EDGE COMPACT ETS code, the radiotelephone device may synchronize and receive in a GSM/EDGE CLASSIC mode).

In addition, the radiotelephone device may perform more than one correlation or more than one synchronization attempt. Fig. 7 shows a flowchart 700 illustrating the method of discrimination of a second embodiment of the present invention. In step 702, the radiotelephone device receives a transmission including a synchronization burst.

In step 705, the radiotelephone device chooses a first ETS code. The first ETS code may be a GSM/EDGE CLASSIC ETS code or an EDGE COMPACT ETS code, both of which may be stored in the radiotelephone device. In step 710, the radiotelephone device correlates the received synchronization burst to the first ETS code.

In step 713, the method determines whether the received synchronization burst substantially correlates to the first ETS code. If it did substantially correlate, the radiotelephone device continues synchronizing and receiving in the mode of the first ETS code.

In step 717, if the received synchronization burst did not substantially correlate to the first ETS code, the radiotelephone device correlates the received synchronization burst to a second, alternate ETS code. If the first ETS code is a GSM/EDGE CLASSIC ETS code, the second code may be an EDGE COMPACT ETS code, etc. In this manner, the radiotelephone device can synchronize to a received transmission in either the GSM/EDGE CLASSIC mode or in the EDGE COMPACT mode, and can accommodate transmissions in more than one mode. These multiple mode transmissions may be handled by_. a mobile station substantially simultaneously.

Although the invention has been described and illustrated with a certain degree of particularity, it is understood that the present disclosure of embodiments has been made by way of example only and that numerous changes in the arrangement and combination of parts as well as steps may be resorted to by those skilled in the art without departing from the spirit and scope of the invention as claimed.

Claims

What is claimed is:CLAIMS

1. A method for discriminating between an EDGE COMPACT and a GSM/EDGE 5 CLASSIC mode in a radiotelephone transmission received by a radiotelephone device, comprising the steps of: receiving a synchronization burst in said radiotelephone transmission; correlating said synchronization burst to an ETS code contained within said radiotelephone device, said ETS code being either an EDGE COMPACT ETS code or a l o GSM EDGE CLASSIC ETS code; and continuing reception of said radiotelephone transmission if said synchronization burst substantially correlates to said ETS code; wherein said EDGE COMPACT ETS code is substantially orthogonal to said GSM/EDGE CLASSIC ETS code. 15

15 2. The method according to claim 1, wherein if a correlation to said EDGE COMPACT

ETS code fails, said method synchronizes to said GSM/EDGE CLASSIC ETS code, and wherein if a correlation to said GSM/EDGE CLASSIC ETS code fails, said method synchronizes to said EDGE COMPACT ETS code.

3. The method according to claim 1, wherein if said synchronization burst of said 20 radiotelephone transmission does not substantially correlate, said radiotelephone transmission is determined to be of an improper type.

4. The method according to claim 1, wherein said GSM/EDGE CLASSIC ETS code is a pseudo-noise sequence.

5. The method according to claim 1, wherein said EDGE COMPACT ETS code is a pseudo-noise sequence.

6. The method according to claim 1, wherein a base station encodes either said

GSM/EDGE CLASSIC ETS code or said EDGE COMPACT ETS code into a transmission.

7. The method according to claim 1, wherein in a transmission from a mobile station said mobile station uses an ETS code identical to an ETS code received from a base station.

8. The method according to claim 1, wherein an ETS code has a minimum cross- correlation with ETS codes of other modes.

9. The method according to claim 1, wherein a GSM/CLASSIC specific ETS code synchronizes and demodulates in a SCH channel and fails to synchronize or demodulate in a CSCH channel, and an EDGE COMPACT specific ETS code synchronizes and demodulate in said CSCH channel and fails to synchronize or demodulate in said SCH channel.

10. The method according to claim 1, wherein said EDGE COMPACT ETS code for decoding in a CSCH mode comprises a bit sequence (1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0,1,0,0,1,1,1,0).

11. The method according to claim 1, wherein said EDGE COMPACT ETS code for decoding in a CSCH mode comprises a bit sequence (1, 1,0, 1, 1, 0, 0, 0, 0, 1, 1,0, 1, 1, 1,0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1,0,0,1,1,1,0,1).

12. The method according to claim 1, wherein said radiotelephone device is capable of operating under GSM, GPRS-136HS EDGE COMPACT, EDGE CLASSIC, and EGPRS-136 modes.

13. The method according to claim 1, wherein said radiotelephone device is capable of operating under GSM, GPRS-136HS EDGE COMPACT, EDGE CLASSIC, and EGPRS-136 modes substantially simultaneously.

14. A method for discriminating between an EDGE COMPACT and a GSM/EDGE CLASSIC mode in a radiotelephone transmission received by a radiotelephone device, comprising the steps of: receiving a synchronization burst in said radiotelephone transmission; choosing a first ETS code from an EDGE COMPACT ETS code or a GSM/EDGE

CLASSIC ETS code contained within said radiotelephone device; correlating said synchronization burst to said first ETS code; continuing reception of said radiotelephone transmission if said synchronization burst substantially correlates to said first ETS code; and correlating to a second ETS code if said synchronization burst does not substantially correlate to said first ETS code; wherein said EDGE COMPACT ETS code is substantially orthogonal to said GSM/EDGE CLASSIC ETS code.

15. The method according to claim 14, wherein in a transmission from a mobile station said mobile station uses an ETS code identical to an ETS code received from a base station.

16. The method according to claim 14, wherein said EDGE COMPACT ETS code for decoding in a CSCH mode comprises a bit sequence (1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0).

17. The method according to claim 14, wherein said EDGE COMPACT ETS code for decoding in a CSCH mode comprises a bit sequence (1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1).

18. A radiotelephone device capable of discriminating between a GSM EDGE CLASSIC mode transmission and a EDGE COMPACT mode transmission, comprising: an antenna; a radio communications device connected to said antenna; a CPU communicating with said radio communications device; and a burst processor communicating with said CPU and with said radio communications device, said burst processor storing a GSM/EDGE CLASSIC ETS code, an EDGE COMPACT ETS code that is substantially orthogonal to said GSM/EDGE CLASSIC ETS code, or both; wherein said burst processor receives a synchronization burst in a radiotelephone transmission, correlates said synchronization burst to an ETS code contained within said radiotelephone device, and continues reception of said radiotelephone transmission if said synchronization burst substantially correlates to said ETS code.

19. The radiotelephone device according to claim 18, wherein said radiotelephone device is capable of operating under GSM, GPRS-136HS EDGE COMPACT, EDGE CLASSIC, and EGPRS-136 modes substantially simultaneously.

20. The radiotelephone device according to claim 18, wherein said radiotelephone device stores both said GSM EDGE CLASSIC ETS code and said EDGE COMPACT ETS code, and if a correlation to said EDGE COMPACT ETS code fails, said method synchronizes to said GSM EDGE CLASSIC ETS code, and wherein if a correlation to said GSM/EDGE CLASSIC ETS code fails, said radiotelephone device synchronizes to said EDGE COMPACT ETS code.