CN1207223A - High-penetration transmission method for a radiocommunication system - Google Patents

Abstract

A method and system for increasing the signal margin of a radiocommunication link to provide a short message service which is reliable, even under non-ideal conditions. According to the method, an increase in transmission power is used in combination with bit repetition to increase signal margin without complications in the mobile unit design, significant delay, or co-channel interference. Where a more significant increase in signal margin is desired, when a longer message is required, or for voice messages, the message may be stored and the mobile unit alerted of the message.

Description

The high osmosis transmission method of radio communications system

The present invention relates generally to radio communications system, more particularly relate to the system and method that under non-ideal condition, sends radiocommunication signals reliably.

Referring to Fig. 1, represent typical cellular mobile radio communication system.This canonical system comprises the many base stations of similar base station 110 and the many mobile units or the station of similar mobile radio station 120.Can utilize these equipment or its equivalent to carry out speech and/or data communication.This base station comprises control and the processing unit 130 of linking MSC (mobile switching centre) 140, and MSC140 links the public switched telephone network (not shown) again.

Base station 110 is served mesh and is comprised a plurality of voice channels of being handled by voice channel transceiver 150, and voice channel transceiver 150 is controlled by control and processing unit 130.Each base station also comprises the control channel transceiver 160 that may handle an above control channel.Control channel transceiver 160 is controlled by control and processing unit 130.Control channel transceiver 160 Broadcast Control Channel on the control channel of base station or mesh is given the mobile radio station that locks onto that control channel.The broadcasting of voice channel transceiver can comprise the business or the voice channel of digital control channel positional information.

When mobile radio station 120 entered idle pulley first, it scanned the control channel of base station of similar base station 110 periodically to search whether the paging of addressing mobile radio station 120 pulse train is arranged.Locked or the preemption of this paging pulse train notice mobile radio station 120 which mesh.Mobile radio station 120 is received in the absolute and relative information of broadcasting on the control channel on its speech and control channel transceiver 170.Then, processing unit 180 is assessed the control channel information that comprises candidate's mesh feature that is received and is determined which mesh this mobile radio station should lock onto.The control channel information that is received not only comprises the absolute information that relates to the mesh relevant with it, and comprises the relative information that relates near other mesh of the control channel mesh relevant with it.When monitoring the master control channel, periodically scan these adjoining cells to have determined whether more suitably candidate.The additional information of the details of implementing about mobile radio station and base station can be in the U.S. Patent Application Serial 07/967 that is entitled as " multi-mode signal processing " of application in the 27 days October in 1992 of P Dent and B.Ekelund, find in 027, it is all quoted at this as a reference.To recognize: the base station can utilize in the satellite-based mobile radio communicaltions system one or multi-satellite to substitute.

In order to increase the radio communications system capacity, can use digital communication and such as frequency division multiple access (FMDA), time division multiple access (TDMA) multiple access technology with code division multiple access (CDMA), the purpose of each of these multiple access technologies is in such a way will be from the signal combination of various information source to the common transport medium, so that can separate different channels and not have the phase mutual interference in its destination.In the FDMA system, the user shares the radio-frequency spectrum in the frequency domain.Be distributed in a part of frequency band that uses during the whole talks for each user.In tdma system, the user shares the radio-frequency spectrum in the time domain.Each radio channel or carrier frequency are divided into a series of time slots, and distribute a time slot for each user, the user inserts and distributes to the whole frequency band (broadband TDMA) of system or only be a part of frequency band (narrow band TDMA) during the crack at this moment.Each time slot comprises the information " pulse train " from data source, for example the digital coding part of voice dialogues.Time slot is combined as the continuous T DMA frame with scheduled duration, and the number of timeslots in each tdma frame is relevant with the different user quantity that can share this radio channel simultaneously.If each time slot allocation of tdma frame is given different users, then the duration of tdma frame is to distribute to minimum time amount between same user's the continuous time slot.CDMA combination FDMA and TDMA.In cdma system, distribute the pseudorandom user code of a uniqueness so that insert the frequency time-domain uniquely for each user.The example of CDMA technology comprises spread spectrum and frequency hopping.

In tdma system, what distribute to same user is not the digital service channel that adjacent continuous time slot constitutes the user usually on the radio carrier frequency, and this digital service channel thinks to distribute to user's logic channel.The formation of TDMA channel is that example shown is in Fig. 2 with the GSM standard.The TDMA channel comprises Traffic Channel TCH and signaling channel SC.The TCH channel comprises full rate and half-rate channel, is used to send speech and/or data-signal.Signaling channel SC transmits signaling information between mobile unit and satellite (or base station).Signaling channel SC comprises three class control channels: Broadcast Control Channel (BCCH), the public control channel of sharing between a plurality of users (CCCH) and distribute to the Dedicated Control Channel (DCCH) of unique user.BCCH generally comprises frequency correction channel (FCH) and synchronizing channel (SCH), and these two channels all are downlink channel.Public control channel (CCCH) comprises down link paging channel (PCH) and access permission channel (AGCH) and uplink random access channel (RACH).Special-purpose control channel DCCH comprises fast associated control channel (FACCH), slow associated control channel (SACCH) and Dedicated Control Channel (SDCCH) independently.Slow associated control channel is distributed to business (speech or data) channel or is given independently Dedicated Control Channel (SDCCH), and the SACCH channel provides power and framing control and control information to mobile unit.

Random Access Channel RACH is used to ask connecting system by mobile radio station.The RACH logic channel be the unidirectional uplink channel (from mobile radio station to the base station or satellite) and share (RACH of each mesh is enough canonical system, even using time of stress) by mobile unit independently.Mobile unit monitors that continuously the RACH channel status is to determine that channel is busy or spare time.If the RACH channel idle wishes that the mobile unit that inserts sends to base station or satellite with its mobile identification number with desirable telephone number on RACH.MSC is from the base station or satellite receives this information and distribute idle voice channel to give mobile radio station, and gives mobile radio station by base station or satellite transmission channel identification, so as mobile radio station can with it own be tuned to new channel.All time slots on the RACH uplink channel or on the contention basis or keeping and to be used for mobile radio station on the basis and to insert request.Be described in the Application No. of submitting on October 25th, 1,993 08/140467 that is entitled as " in mobile radio system, implementing the method for access at random " based on the access that keeps on the basis, and this application is quoted at this as a reference.A key character of RACH operation is: require to receive a certain downlink information, thereby mobile radio station receives the real-time feedback of each pulse train that they send on up link.This is called the 2nd layer ARQ or automatic repetitive requests on the RACH.Downlink information preferably includes 22 bits that can think to be exclusively used in another downlink subchannels that transmits the 2nd layer of specific information of up link in down link.This information flow that can be described as shared channel feedback strengthens the handling capacity of RACH, so that mobile radio station can promptly determine whether successfully to receive arbitrary pulse train of arbitrary access attempts.As shown in Figure 2, this downlink information sends on channel AGC H.

Signal in the tdma system transfers out in present buffering and burst or the discontinuousness transmission mode: each mobile unit only sends during its distributed time slot in tdma frame on the frequency that mobile unit distributes or receives.On full rate, for example, mobile radio station may send during the time slot 1, receive during the time slot 2, idle during the time slot 3, sending during the time slot 4, receiving during the time slot 5 and idle during time slot 6, and repetitive cycling during follow-up tdma frame subsequently.Can be that battery powered mobile unit can be turned off (or " sleep ") to save power during neither sending the time slot that does not also receive.

In order to increase mobility and portability, the mobile unit of the radio communication user is tending towards preferably having relatively little omnidirectional (and therefore less power) antenna rather than have mobile unit big or directional antenna.Because this is preferred, sometimes the signal strength signal intensity that is difficult to provide enough is used for the signal of communication exchange between the general mobile unit with little omnidirectional element and mobile switching centre (MSC) or satellite, and this problem is particularly serious in satellite-based mobile radio.

Satellite-based mobile radio communicaltions system utilizes one or more partly overlapping satellite beams that the particular locality of radio communication services to the earth is provided.Each satellite beams has the radius up to about 1000KM.Because the Power Limitation of satellite, it is unpractiaca providing high link margin simultaneously in each wave beam.

Because the mobile-satellite link strictly carries out Power Limitation, communication generally is restricted to the line-of-sight channel with Ricean decline.The decline los path of improving oneself and of Ricean with the combination of the ground-reflected wave of weak building reflected wave.These channels about 8dB of requirement or communication link surplus still less obtain the Speech Communication in ideal or the approximate ideal condition, such as the Speech Communication when the correct expansion of mobile radio telephone antenna is in unobstructed position with this telephone set.In the channel of these approximate ideals, mobile unit successfully monitors to detect incoming call.Under non-ideal condition,, comprise that the reflected wave of ground return and building reflected wave becomes main such as not launching at the mobile unit antenna or mobile unit when being in the blocking position (for example, in building).Channel in these non-ideal conditions is characterised in that: smooth Rayleigh (Rayleigh) decline decline of strict type () with serious decay.In such channel, require 30dB or more link margin to obtain Speech Communication, and the mobile unit monitors have difficulty to detect incoming call.In the very difficult non-ideal condition that carries out of these Speech Communications, wish short messenger service (SMS).Because the Power Limitation of satellite, SMS is especially effective when being used for non-ideal condition and with warning mobile radio station user incoming call being arranged.The mobile radio station user can change the position subsequently and receive or return calling.Term " link margin " or " signal margin " refer to provide the desired secondary power of enough services and ideal conditions be channel except that additional Gaussian noise (AWGN) without any the condition of damage under desired power." damage " comprises irregular in decline, Doppler frequency shift, phase change, signal shade or obstruction, enforcement loss and the antenna pattern of signal amplitude.

No matter be to send speech or data, wish to increase signal margin often and guarantee reliable radio communication performance, especially in the satellite application of Power Limitation.The known method that increases the link margin of signal comprises spread channel bandwidth, increases signal power and bit repetition, the known method that each method of these methods has tangible restriction, bandwidth expansion general using such as signal extension and low bit rate error correction coding obtains, and obtains the more insensitive signal of decline.The bandwidth expansion reduces spectrum allocation may efficient.And, in SMS uses,, then in mobile unit, will require two independent and complete wireless devices (one of each service), thereby make its design complicated if the spread bandwidth of voice channel is different with the bandwidth of message channel.Also have, generally also require coherent rake receiver or equalizer to reduce and postpone expansion, this further makes the design of mobile unit more complicated.Bandwidth expansion also can utilize repeating to transmit and implementing of whole speech or data-message.Yet under interested non-ideal condition, this method is invalid, and this is because repeat generally (that is, do not have enough surpluses) below noise lower bound (floor) at every turn, causes high error rate and stops the coherent integration that repeats.

Also can increase signal power and be used to the surplus that provides higher.Because the Power Limitation of satellite, this generally is not actual solution.Except increasing system cost, the through-put power of increase also makes the control co-channel interference more difficult, especially in the tdma system with narrow multiplexing surplus.Therefore, the high-power increase from satellite to mobile unit also only provides between the operating period of relative light load.And, be subjected to Power Limitation more owing to mobile unit even than satellite, so this technology is actual only generally a direction from satellite to mobile unit.

Bit repeats also to can be used for increasing surplus, and bit repeats to utilize and repeats lower error rate than message and finish, especially under non-ideal condition.Obviously bit repeats to cause transmission delay, and this is undesirable for voice signal.Yet, suppose to postpone to remain rational minimum that transmission delay is acceptable for data communication, such as the SMS characteristic.Obtain bit by the grouping that repeatedly sends each bit or modulated symbol or bit or modulated symbol and repeat, so that all duplicate packages are contained in the identical time slot of continuous T DMA frame.The receiver integration from the energy of each repetition so that generate signal with higher surplus.As mentioned above, according to message-length, bit repeats to cause tangible delay.In order to obtain the 30dB signal margin, each bit must repeat 1000 times.General short message has character between 32 and 64 in the gsm system of European digital standard, in DAMPS (digital advanced mobile phone service) system that the U.S. uses at present nearly 245 characters and in DECT (digital europe cordless telephone) system 160 characters nearly.Suppose that gsm system has the tdma frame of 18.64ms, every frame 16 time slots and 114 data bits/time slot, the minimum delay that does not comprise the propagation time that is used to receive 64 character informations is as follows:

64 bits * 8 bits/character * 1000 repetition/bits * 18.64ms/ time slot * 1/114 time slot/data bit=84 second

Even for transfer of data, such delay also is extremely undesirable.Therefore, wish the signal transmission of the signal margin that radio communications system allow to increase and significantly do not postpone and be provided with significant increase power.

Also wish communication system allow to have increase signal margin the signal transmission and do not require the expansion of channel width.

Also wish the tdma communication system allow to have increase signal margin the signal transmission and do not require the variation of the structure or the formation of tdma frame.

Also wish signal margin that mobile radio communicaltions system allow to utilize increases or from the transmission of mobile unit or the data-message that starts from satellite or base station.

Wish that also communication system increases the signal margin that is used for the data-message communication link transmitting selectively.

Above-mentioned and other restrictions of general communication system and method utilize the present invention to overcome, and the invention provides the high osmosis transmission method, and the combination that utilizes bit to repeat to increase with less power in the method increases signal margin.According to exemplary embodiment, the combination that bit repeats to increase with less power avoids only depending on the unacceptable lag characteristic of the system that repeats to increase signal margin.Equally, repeat to avoid only depending on the cochannel interference problem that the power increase increases the system of signal margin with the combination of less power increase.

According to exemplary embodiment of the present invention, mobile radio communicaltions system has the short message service characteristic, is used to send alphanumeric message and sends alphanumeric message to mobile unit with from mobile unit.In order to guarantee in the reliable transmission that has on the channel of serious decay, communication system is utilized the error detection coding short message of encoding; Message is divided into each grouping with one or more bits or group; Each grouping utilizes the identical time slot of each transmission to send repeatedly with the power level greater than the power level that is used for speech transmissions on the tdma communication channel; And on receiver, integration and error check are carried out in transmission and have the signal that increases surplus with formation.

To more easily understand aforementioned purpose of the present invention, characteristic and advantage on the basis of below reading in conjunction with the accompanying drawings, describing in detail, wherein:

Fig. 1 is the block diagram of exemplary mobile radio communicaltions system;

Fig. 2 is illustrated in the figure that channel constitutes in the typical GSM digital radio communication system;

Fig. 3 is the figure that wherein can adopt the satellite-based mobile radio communicaltions system of method for transmitting signals of the present invention; With

Fig. 4 is the flow chart of describing according to short message transmission of the present invention.

Though following description at the short message service of adopting in satellite-based radio communications system, should be recognized: the present invention also can be applied to the communication system of other types.

In satellite-based mobile radio communicaltions system, be used to send combination that the communication link of speech or data can be by satellite, multi-satellite or a multi-satellite and PSTN (public switched telephone network) mobile radio station and or the telephone set of standard or second mobile radio station between set up.As shown in Figure 3, may wish that such system obtains wide geographical coverage area, it is unpractiaca such as imitating the district wherein existing few or not having the base station and increase the base station.Because the intrinsic Power Limitation of satellite, the voice communication link between satellite and the mobile radio station requires the condition of ideal or approximate ideal; That is, such as the horizon communication that utilizes the mobile radio station antenna correctly to launch.In non-ideal condition, such as when mobile radio station crested (for example, in building, or the like) or when the mobile radio station antenna did not correctly launch, because the decay that increases in the channel, the power of communication or signal margin required to increase significantly.In this situation (being expressed as MUZ in Fig. 3), Rayleigh fading stops gratifying communication often, and therefore wishes to send short alphanumeric message to mobile radio station, and for example this message can be used for notifying the user that incoming call is arranged.The reliable transmission of message is provided by the effective technology that provides the increase signal margin not have remarkable delay, power increase or co-channel interference in the present invention.

Only be used for illustrative purpose and do not limit the purpose of category of the present invention, use the satellite-based gsm radio communication system of TDMA channel to think and present following state.Communication channel does not have the sighting distance composition and is had the flat Rayleigh fading of serious decay.As those skilled in the art are aware, Rayleigh (or multipath) decline be since in the coverage from actual building reflection and the multipath ripple form standing wave to the time phenomenon that occurs.Add together standing wave to forming irregular wave decline structure.When mobile unit was static, it received constant signal.Yet when mobile unit moved, decline appearred in the decline structure, moved at mobile unit that decline increases when faster.The average signal level of imperfect Rayleigh channel is than the low about 20-30dB of signal level of the line-of-sight channel of approximate ideal.

In order to guarantee that the short message reliable transmission is given mobile unit in non-ideal condition, must increase signal margin.Can combined bit according to the present invention repeat and the power increase provides the signal margin of increase and do not have tangible delay.

To recognize: decibel (dB) is the unit that is used to represent power, curtage ratio.Specifically, power ratio (P2/P1) can utilize formula dB=10log (p2/p1) to represent with decibel.Because 10log 1000=30, the signal margin of 30dB requires 1000 power ratio, therefore, repeats to obtain this signal margin in order only to utilize bit, each bit must repeat 1000 times and must be at the each signal margin that repeats of receiver integration, postpones in 82 seconds that obtain as above being calculated.Yet in order to obtain the 15dB surplus, desired power ratio only is 31.623, and this is because 10log31.623=15.Therefore, can provide the 30dB signal margin by increasing power 15dB and repeating each than contributing 31 times.Use this technology, the bit duplicate delays of 64 character informations is (64 characters * 8 bits/character * 31 repetition/bits * 18.64ms/ time slot * 1/114 time slot/bit) about 2.5 seconds.As a result, the bit duplicate delays remains on the reasonable levels, and the power increase also remains on the reasonable level, thereby avoids co-channel interference.To recognize: do not have remarkable delay in order to obtain communication successful in the Rayleigh fading environment, the many various combinations that repeat to increase with power are possible.And, do not repeat each bit of digital signal, and can the repetition bits group.

In order to implement the technology of the present invention, the power termination by average multi-user can provide the power from satellite to mobile radio station to increase.That is, the employed communication channel of mobile unit can make its power reduce and give mobile unit so that increase power supply under non-ideal condition in the approximate ideal condition.The power increase also can utilize time average to provide, and wherein each time slot sends with the power level that increases in continuous T DMA frame.To recognize: the power that also can utilize other technologies well known in the art to obtain from satellite to mobile radio station increases.

The Power Limitation of mobile unit even severeer than the Power Limitation of satellite.Therefore, increase power from mobile radio station to satellite communication even more difficult, such communication must send the reception of message or acknowledge message.According to one embodiment of present invention, the power increase from mobile unit to satellite can be sent acquisition at all time slots of Random Access Channel RACH by allowing mobile unit.Bit repeats also can be used for further increasing effectively the signal margin that sends to satellite by mobile unit.Because mobile unit is approved really in order to finishing with the signal with low information rate on the RACH channel, so the bit of the synchronization bit of the greater number higher quantity relevant with forward channel and message repetition can be used to compensate the lower through-put power of mobile unit.Preferably, mobile unit sends on independent carrier frequency and repeats continuously so that decorrelation should repeat.Because message is short, the transmission time will be lack and average transmitting power to use this system will be acceptable.

Now referring to Fig. 4, the flow chart of the short message transmission of utilizing transmission method of the present invention is described in expression.In step 100, the transmit leg input will send to the message that receives the user, this message can directly be imported into communication system by transmit leg by mobile unit, standard telephone set, terminal or equivalent of the apparatus, and maybe can importing this message into by calling, the operator of the service centre of system directly imports this message.In step 102, comprise that the information bit of short message is encoded by the error detection code that is positioned at encoder utilization such as the CRC on the transmitter.Coded message constitutes the code word bits of some quantity X or the code word of code element.Will be appreciated that: transmitter can be satellite, base station or mobile unit.In step 104, each X code word bits or the code element exported by code device repeat N time to form a grouping that comprises the N bit.Obviously: do not repeat each bit or code element, and can repeat the group of two or more bits or code element.Send grouping subsequently,, make the receiver can estimating channel quality so that each time slot in the tdma frame comprises the grouping of one or more repetition bits, error detection coding bit and synchronization burst.All bits that comprise the short message of coding send by this way.In case sent the message of whole coding, the transmission of message (with the block form of N code word bits) repeats M time to obtain desirable signal margin.To recognize:, in each equipment of these equipment, provide coding and sending function owing to can send SMS message from satellite, base station or mobile radio station.Also should recognize: in order to adopt technology of the present invention, device is included in the quantity that the bit that needs with the desired signal margin of the transmission of messages that is defined as succeeing in the transmitter repeats N, message repetition M and power increase.

In step 108, receiving equipment (that is, mobile unit, satellite, base station or equivalent of the apparatus) sampling comprises the received signal of coded message, detection bits and the channel quality evaluation bit of repetition, and generation form is $r_j=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}|r_{\mathrm{ij}}-{\hat{C}}_j{S}^2|$ Measure and, r wherein _IjBe the received signal of the sampling of corresponding grouping the i time repetition repeating information bit among the j or code element S, and Cj is corresponding channel quality evaluation.In step 110, be included in decoder in the receiving equipment utilize soft combination or majority logic voting or the decoding of other suitable coding/decoding methods from measure and tdma slot in the bit or the code element of each coding.In order to realize soft combination, decoder adds tolerance and is r= $\underset{J=1}{\overset{M}{\mathrm{\Σ}}}{r}_j$ , and according to this with carry out bit or code element and judge.In order to adopt the majority logic voting, decoder is measured y to each _iThe bit or the code element of carrying out are in advance judged, and are carried out last bit or code element judgement by relatively more all judging in advance subsequently.Therefore, judge in advance if decoder has carried out M time, if more than half be judged to be 1 in advance, then decoder will determine that corresponding information bit is 1; Otherwise decoder will determine that corresponding information bit is 0.It is 0 bit that identity logic is used to decode.For just prevent to cause judging in advance of half be 0 and just half judgement in advance be 1 mistake, selection M is an odd number.The bit of decoding coherently makes up and a plurality of transmission of messages coherently makes up the message signale that has the increase surplus with generation.

In step 112, the error detector that is included in the receiving equipment detects mistake according to the CRC error detection coding that provides on transmitting apparatus.If do not detect mistake, then on reception user's mobile unit, show this message in step 114.If the mistake of detecting, then message does not show on receiving equipment, utilize the error message that shows or utilize audio signal to notify the user that error message is arranged, and receiver request transmitter is according to the mistake part of the following protocol retransmission message of two-way radio in greater detail or this message.

According to the present invention, the repeating of message sends and can use with the repeated combination of message various piece.That is, the various piece of message can send repeatedly, and has utilized the repeating to send of message part and when sending, can send whole message once more in whole message.

According to a further aspect in the invention, message repeats for example by on different frequencies, in different polarization or with suitable time delay transmission message or message part decorrelation.

Transmission system of the present invention may further include forward error correction (FEC) device.In such arrangement, transmitter is equipped with second encoder, utilizes the information bit of error correcting code coding short message after step 102 is utilized the error detection code coded information bits.Send the message of message and decoding reception with said method.As for majority logic voting, adopt the hard decision decoder, and the bit of majority logic voting machine output is presented and is not had additional information (such as the bit reliability information of coming the self-channel estimation) to channel decoder.If use soft combination, adopt the soft decision decoding device to come the decoding and error sign indicating number, and tolerance and yi be added to the output of soft decision decoding device, and this and present to error correction decoder.If the output of the difference of error correcting encoder interlocks by the output bit that separately links to each other in transport stream as much as possible, error correction coding will be more effective.

To recognize: bit and message number of repetition are high more, and systematic function will be good more, but delay will be longer.A tdma slot has the bit of the limited quantity that can be used as synchronizing information or data.Increase bit number of iterations (N) inevitable requirement synchronization bit quantity minimizing in the grouping.Measure and depend on the channel quality of estimation, and channel quality depends on synchronization bit quantity.If a tdma slot has the Nt bit, Ns synchronization bit/time slot and every time slot Nt-Ns data bit are then arranged, the every bit snr gain that is then caused by repetition is about (NtNs-Ns2)/Nt.Optimum signal-noise ratio gain thereby when appearing at Ns=Nt/2.Yet will recognize: the selection of the quantity of synchronization bit and data bit will be depended on the concrete transmission plan that will adopt in given time slot.

As mentioned above, the link of setting up in order to transmit message between satellite and the mobile radio station is a two-way link.Therefore, radio protocol can be selected to be used between satellite and the mobile radio station to strengthen the practicality of short-message system.For example, can adopt a simple protocol, whether the mobile radio station that receives message in this agreement will utilize " YES (being) " or " NO (denying) " to respond satellite and correctly receive with expression message.Selectively, can adopt more complicated agreement, the group utilization group ID of grouping or grouping discerns and utilizes the CRC error detection code to protect in this agreement.If CRC represents correctly not receive message, then satellite can be retransmitted the grouping that comprises groups of errors.In this method, whole message is opposite with retransmitting, and only need resend the grouping of mistake.Therefore, this agreement can be used for optimizing number of repetition, thus and the satellite power minimum that makes delay and waste.

Also provide the advantage of gateway to charge according to the two-way link of SMS of the present invention.One way link stops the short message of collecting to sender or recipient to transmit expense, and this is because there is not the correct evidence that receives of relevant information.Therefore, the SMS business with one way link can offer the user with the rate that increases.On the contrary, because two-way link allows sender of the message or service operations person to determine whether message correctly receives, so the ISP can only utilize the transmission expense of each correct message that receives that SMS is provided business.

As mentioned above, for long message, Speech Communication or the requirement condition greater than the 30-40dB link margin, unacceptable long delay may cause technology of the present invention.In such a case, can store this message at satellite or corresponding honeycomb mobile switching centre (MSC).When mobile unit can be read the Broadcast Control Channel (BCCH) of more favourable communication channel, can utilize the mark on the Broadcast Control Channel for example to tell this element with the message of storage.

Utilize technology of the present invention, the signal margin of increase can be provided and not have bandwidth expansion, thereby avoid complicated mobile radio station design.And, except message content, for the not variation of requirement of tdma frame structure or formation.Method of the present invention allows signal to send to mobile radio station or sends from mobile radio station.Because the method is two-way, the system of it will be appreciated by those skilled in the art that can be embodied as the part of signal controlling channel in the tdma system.

Claims (34)

1. be used to increase a kind of method of communication link surplus, comprise:

Set up communication link with initial surplus level between transmitter and receiver, this communication link has a plurality of time slots, and each time slot comprises a plurality of information bits;

On communication link, repeatedly send information signal one or more group of information bits to receiver from transmitter, every group be sent in same time slot at every turn and to occur with middle surplus level between the surplus level of initial surplus level and increase; With

The signal that has the surplus level of increase in the transmission of every group of receiver integration with formation.

2. according to the method for claim 1, also comprise step: before forwarding step, utilize each transmission of encoding of error detection coding information.

3. according to the method for claim 2, also comprise step: before integration step, utilize soft combination decoded information bit.

4. according to the method for claim 1, also comprise step: determine the whether success of transmission of information signal, and if the transmission of information signal is unsuccessful, then the information bit of stored information signal is so that send to receiver later on.

5. according to the process of claim 1 wherein that transmitter is a satellite, and receiver is a mobile telephone unit.

6. according to the process of claim 1 wherein that transmitter is a mobile telephone unit, and receiver is a satellite.

7. according to the method for claim 6, wherein information signal is a confirmation signal.

8. according to the method for claim 7, wherein on the Random Access Channel of mobile radio link, send confirmation signal.

9. according to the process of claim 1 wherein that information signal is an alphanumeric message.

10. according to the process of claim 1 wherein that communication link is a two-way link.

11. according to the process of claim 1 wherein that communication link is a Rayleigh channel.

12. according to the method for claim 4, also comprise step: notice receiver information signal is stored.

13. a communication system comprises:

Transmitter is used for sending information signal with first power level, and this transmitter comprises the device that is used for repeatedly sending with second power level information signal part;

Receiver is used to receive the part of these parts and integration reception to form the information signal of integration.

14. according to the communication system of claim 13, wherein transmitter also comprises the encoder that utilizes error detection coding to come encoded information signal, and wherein receiver comprises the decoder of the part that receives of being used to decode.

15. according to the communication system of claim 14, wherein each part comprises one or more bits of information signal.

16. according to the communication system of claim 13, wherein transmitter is a satellite, and receiver is a mobile telephone unit.

17. according to the communication system of claim 13, wherein transmitter is a mobile telephone unit, and receiver is a satellite.

18., wherein on the Random Access Channel of mobile radio link, send information signal according to the communication system of claim 17.

19. communication system according to claim 14, wherein whether transmitter communicates by letter successful with the transmission of definite information signal with receiver, if and the transmission of information signal is unsuccessful, then the information bit of memory device stores information signal is so that send receiver later on to.

20. according to the communication system of claim 19, wherein transmitter notice receiver, information bit are just stored by storage device.

21. according to the communication system of claim 14, wherein information signal is an alphanumeric message.

22. according to the communication system of claim 14, wherein decorrelation is by the part of transmitter transmission.

23. according to the communication system of claim 14, wherein transmitter also comprises the error correcting encoder that utilizes error correction coding to come encoded information signal, and receiver also comprises the error correction decoder of the receiving unit that is used to decode.

24. be used to send a kind of method of data, comprise step:

The data of utilizing error detection coding to encode will to send are to form code word data;

Code word data is divided into the grouping that each has one or more data bits;

Repeatedly send each grouping with first signal margin on the communication channel of setting up between transmitter and the receiver, this communication channel transmits voice signal with the secondary signal surplus, and this secondary signal surplus is lower than first signal margin;

In receiver this grouping of sampling;

Decoded packet; With

The grouping of integration decoding has the data-signal of the 3rd signal margin with formation, and this 3rd signal margin is higher than first signal margin.

25., wherein utilize soft combination to carry out decoding step according to the method for claim 24.

26., wherein utilize the hard decision decoding to carry out decoding step according to the method for claim 24.

27. according to the method for claim 24, wherein data-signal is an alphanumeric message.

28. according to the method for claim 24, wherein transmitter is a satellite, and receiver is a mobile telephone unit.

29. according to the method for claim 24, wherein transmitter is a mobile telephone unit, and receiver is a satellite.

30. according to the method for claim 29, wherein data-signal is to be used for the affirmation signal that acknowledge message receives.

31., wherein on the Random Access Channel of mobile radio communicaltions system, send confirmation signal according to the method for claim 30.

32., also comprise step according to the method for claim 27:

Determine at receiver whether alphanumeric message comprises any mistake;

If alphanumeric message comprises mistake, then ask resending of one or more groupings; With

If alphanumeric message does not comprise mistake, then show this alphanumeric message at receiver.

33. according to the method for claim 24, the wherein transmission of each grouping of decorrelation.

34., also comprise step: before forwarding step, utilize error correction coding to come coding codeword according to the method for claim 24.

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