CN1933364A - Time slot structure and combining method and apparatus - Google Patents

Abstract

A method for integrating new time slot structure includes integrating at least two time slots to be a new time slot and adjusting train sequence to be at middle of new time slot structure. The device for realizing said method is also disclosed.

Description

A kind of time slot structure and combined method and device

Technical field

The present invention relates to communication technique field, relate in particular to a kind of time slot structure and combined method and device.

Background technology

Under the ever-increasing situation of business, GSM (global system for mobile communications)/EDGE (GSM strengthens speed evolution) network more and more is subjected to the restriction of capacity and speed, various for this reason GSM/EDGE evolution technology continue to bring out, to improve user's peak rate and Mean Speed.

The common structure of time slot of traditional GSM/EDGE as shown in Figure 1, time slot comprises 156.25 symbols altogether, the holding time width is 0.577ms.Wherein, Tail represents the tail bit, each 3 symbol of front and back; Data represents user data segment, and each 58 symbol of front and back during the GMSK modulation, divide 57 information symbols and 1 flag of frame steathily; TSC is a training sequence, is used for receiver synchronous and channel estimating usefulness, totally 26 symbols; Guard Period is protection interval, totally 8.25 symbols.

In order to improve user data rate; present existing technical scheme is on traditional time slot basis; carry out the time slot combination of different numbers; only keep a training sequence and front and back protection interval and tail bit in the new time slot after the combination; remaining training sequence, protection interval and tail bit position are used for transmitting user data, thereby improve the user data utilance of new time slot.

For the combination of n time slot, the new time slot after the combination comprises 156.25 * n symbol; The structure of time slot that has proposed at present has two time slot combinations, the combination of three time slots and multi-slot (greater than three) combination.Comprise 312.5 symbols for the new time slot after two time slot combinations, the new time slot after the combination of three time slots comprises 468.75 symbols, and the new time slot after the combination of four time slots comprises 625 symbols.

New time slot may bring influence to the channel estimating of receiver after lengthening on the duration, in two kinds of situation: a kind of is that new slot time length is less than the channel coherence bandwidth; Another kind is that new slot time length is greater than the channel coherence bandwidth.

For a terminal that moves with speed v, Coherence_Time coherence time of its channel can be estimated by following formula

$\mathrm{Coherence}\_\mathrm{Time}=\sqrt{\frac{9}{16\mathrm{\π}}}\frac{\mathrm{\λ}}{v},$

Wherein, λ is a carrier wavelength; For GSM 900MHz frequency range, even when rate travel is 200km/h, be about 2.5ms the coherence time of channel, is approximately the duration of 4 time slots (each time slot 0.577ms).In the coherence time of channel, the decline of channel big variation can not occur in theory.

Based on top theoretical foundation,, can only keep the channel estimating that a training sequence is used for new time slot when new time slot duration during less than the channel coherence bandwidth.

When duration of multi-slot combination during, can solve the problem that bigger variation appears in channel fading by the channel tracking algorithm greater than the correlated time of channel.

But in the existing technical scheme, make up the training sequence that keeps in the new time slot and do not do locational adjustment, as shown in Figure 2, be combined as example with the GMSK modulation with two time slots, only kept a training sequence in the new structure of time slot, and the relative position of its training sequence is constant, this user data block length that causes may occurring in the new structure of time slot before and after the training sequence is unequal, make the demodulation performance of training sequence front and back data block occur uneven, the demodulation performance that is to say the long data piece is poorer than the demodulation performance of short data block, and this phenomenon is particularly evident for the 8-PSK modulation of EDGE; And two data block lengths differ big more, and its demodulation performance is uneven more.The imbalance of demodulation performance will descend the effect of interleaver, thereby reduces decoding performance.

Summary of the invention

The object of the present invention is to provide a kind of time slot structure and combined method and device, multi-slot combination back is adjusted the position of training sequence, training sequence in the structure of time slot after guaranteeing to make up is positioned over the centre position of new time slot, thereby improves the global solution mediation decoding performance of data.

The objective of the invention is to be achieved through the following technical solutions:

A kind of time slot structure comprises data segment, training sequence, protection end to end at interval, and described training sequence is positioned at the centre position of time slot structure.

Include only a training sequence and protection end to end in the described time slot structure at interval.

A kind of time slot structure composite set comprises:

Training sequence position adjusting module, the time slot structure after being used to obtain to make up according to the number of time slots of combination and the position of current training sequence, is adjusted to described training sequence in the centre position of new time slot.

Described device also comprises:

The structure of time slot composite module provides the interface with training sequence position adjusting module, is used at least two traditional time slots are combined, and keeps a training sequence and protection end to end at interval.

A kind of time slot structure combined method comprises:

A, at least two time slots are combined into time slot structure;

Training sequence in the time slot structure after B, the adjustment combination is to the centre position of new time slot.

Described steps A specifically comprises:

Will at least two the time slots combination, make the new time slot after the combination only keep a training sequence and the interval of protection end to end.

Described method further comprises:

N * 0.25 symbol that a plurality of time slot combinations back is saved is positioned at interval as protection in the middle of the protection at interval of new time slot, and n is the number of time slots of combination.

Described step B specifically comprises:

Determine to constitute the number of time slots of new time slot according to the symbolic number that comprises altogether; determine the symbolic number that protection is occupied at interval according to the number of time slots of forming; thereby can determine to remove the symbolic number after protecting at interval, finally obtain the centre position, the training sequence that keeps is adjusted to the centre position.

As seen from the above technical solution provided by the invention, the present invention is by adjusting the position of training sequence, make up new GSM/EDGE physical layer time slot structure, the unbalance condition of the demodulation performance of data block before and after can improving in the existing combination structure of time slot, thereby improve the global solution mediation decoding performance of data, and for receiver, do not increase the algorithm complex of channel estimating and channel tracking.

Description of drawings

Fig. 1 is the common time slot of prior art GSMK/8PSK tradition;

Fig. 2 is the letter structure of time slot after the combination of prior art two time slots;

Fig. 3 is applied to the time slot structure of GMSK modulation usefulness for the method for the invention;

Fig. 4 is applied to the time slot structure of 8PSK modulation usefulness for the method for the invention.

Embodiment

Core concept of the present invention provides a kind of time slot structure and combined method and device, multi-slot combination back is adjusted the position of training sequence, training sequence in the structure of time slot after guaranteeing to make up is positioned over the centre position of new time slot, thereby improves the global solution mediation decoding performance of data.

The invention provides a kind of time slot structure; form by at least two traditional time slots; this time slot structure is with after a plurality of traditional time slot combinations; training sequence and protection end to end are at interval in the reservation; it comprises several parts such as data segment, training sequence, the interval of protection end to end, and wherein training sequence is positioned at the centre position of time slot structure.

The invention provides a kind of time slot structure composite set, described device comprises at least: structure of time slot composite module, training sequence position adjusting module; Described structure of time slot composite module is used at least two traditional time slots are combined, and keeps a training sequence and protection end to end at interval, removes unnecessary training sequence and protection at interval; Described training sequence position adjusting module provides the interface with the structure of time slot composite module, and the time slot structure after being used to obtain to make up according to the number of time slots of combination and the position of current training sequence, is adjusted to described training sequence in the centre position of new time slot.

The invention provides a kind of time slot structure combined method, a kind of embodiment operating process comprises following operation:

Step 1: the structure of time slot composite module is combined into time slot structure with at least two time slots;

The time slot structure that is illustrated in figure 3 as GMSK (Gaussian minimum frequency shift keying) as, be respectively from top to bottom two, three, structure of time slot after four traditional time slots make up, new time slot after the combination only keeps a training sequence and the interval of protection end to end, n * 0.25 symbol that a plurality of time slot combinations back is saved is positioned in the middle of the protection at interval of new time slot at interval as protection, in Fig. 3, protection after two time slots make up is spaced apart 8.5, protection after three time slots make up is spaced apart 8.75, protection after four time slots make up is spaced apart 9, therefore, along with increasing of time slot data in the combination time slot, protection all increases by 0.25 symbol at interval at every turn;

Figure 4 shows that the time slot structure of 8PSK modulation usefulness, its anabolic process is with the combination operation of the new time slot of GMSK modulation usefulness;

Step 2: the position of training sequence in the time slot structure after the training sequence position adjusting module adjustment combination;

After the new time slot combination; training sequence position adjusting module obtains the time slot structure after the combination; determine to constitute the number of time slots of new time slot according to the symbolic number that comprises altogether; determine the symbolic number that protection is occupied at interval according to the number of time slots of forming; thereby can determine to remove the symbolic number after protecting at interval; the centre position is adjusted to the training sequence that keeps in the final centre position that obtains.

In sum, the present invention is by adjusting the position of training sequence, make up new GSM/EDGE physical layer time slot structure, the unbalance condition of the demodulation performance of data block before and after can improving in the existing combination structure of time slot, thereby improve the global solution mediation decoding performance of data, and for receiver, do not increase the algorithm complex of channel estimating and channel tracking.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims (8)

1, a kind of time slot structure comprises data segment, training sequence, protection end to end at interval, it is characterized in that described training sequence is positioned at the centre position of time slot structure.

2, a kind of time slot structure as claimed in claim 1 is characterized in that, includes only a training sequence and protection end to end in the described time slot structure at interval.

3, a kind of time slot structure composite set is characterized in that, comprising:

Training sequence position adjusting module, the time slot structure after being used to obtain to make up according to the number of time slots of combination and the position of current training sequence, is adjusted to described training sequence in the centre position of new time slot.

4, a kind of time slot structure composite set as claimed in claim 3 is characterized in that described device also comprises:

The structure of time slot composite module provides the interface with training sequence position adjusting module, is used at least two traditional time slots are combined, and keeps a training sequence and protection end to end at interval.

5, a kind of time slot structure combined method is characterized in that, comprising:

A, at least two time slots are combined into time slot structure;

Training sequence in the time slot structure after B, the adjustment combination is to the centre position of new time slot.

6, a kind of time slot structure combined method as claimed in claim 5 is characterized in that described steps A specifically comprises:

Will at least two the time slots combination, make the new time slot after the combination only keep a training sequence and the interval of protection end to end.

7, as claim 5 or 6 described a kind of time slot structure combined methods, it is characterized in that described method further comprises:

N * 0.25 symbol that a plurality of time slot combinations back is saved is positioned at interval as protection in the middle of the protection at interval of new time slot, and n is the number of time slots of combination.

8, a kind of time slot structure combined method as claimed in claim 5 is characterized in that described step B specifically comprises:

Determine to constitute the number of time slots of new time slot according to the symbolic number that comprises altogether; determine the symbolic number that protection is occupied at interval according to the number of time slots of forming; thereby can determine to remove the symbolic number after protecting at interval, finally obtain the centre position, the training sequence that keeps is adjusted to the centre position.

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