CN101442353B - Method for down transmission diversity - Google Patents
Method for down transmission diversity Download PDFInfo
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- CN101442353B CN101442353B CN 200710188029 CN200710188029A CN101442353B CN 101442353 B CN101442353 B CN 101442353B CN 200710188029 CN200710188029 CN 200710188029 CN 200710188029 A CN200710188029 A CN 200710188029A CN 101442353 B CN101442353 B CN 101442353B
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Abstract
The invention discloses a method for downlink transmit diversity, which comprises the following steps: a base station presets a plurality of time delay combinations of various distributed antenna units which can be used for selection; the base station transverses the preset time delay combinations to judge whether at least one time delay combination exists, and the time delay combination, for each terminal in a system, delays a synthesis signal after downlink diversity transmission signals for the terminal reach the terminal from the distributed antenna units to be a resolvable multi-path signal to a terminal receiver; if at least one time delay combination exists, the time delay combination is used to set the transmission time delay on the distributed antenna units and perform the downlink delay diversity transmission; otherwise a downlink delay diversity mode of the system is converted into the selective transmission that optimum distributed antenna units are selected. The method can fully assure the gain produced by a downlink multi-path delay transmit diversity mode through a self-adaptive downlink transmit diversity mode.
Description
Technical field
The present invention relates to communication technical field, relate in particular to a kind of method of down transmission diversity.
Background technology
TD-SCDMA (Time Division-Synchronous Code Division Multiple Access access) base station that is equipped with at present distributed antenna unit puts it into commercial operation, covering to the residential quarter has been finished in more flexible, effective Distributed coverage mode in the TD-SCDMA base station that is equipped with distributed antenna unit, so that terminal can communicate with one or several distributed antenna units nearby, increased the equivalent area coverage of residential quarter, save up and down power, reduced the interference to the whole network.
For the lower line algorithm of the TD-SCDMA base station that is equipped with distributed antenna unit, there is the problem of how terminal being organized suitable distributed downlink emission.At present ripe mode is the diversity transmission of selecting the selectivity emission of Optimal Distribution formula antenna element and selecting a plurality of more excellent distributed antenna units, and the former implication is that the base station is selected a distributed antenna unit optimum for certain terminal and carried out downlink; The latter's implication is that the base station is selected a plurality of more excellent distributed antenna units and launched together downstream signal, adopts simultaneously certain diversity mode to be beneficial to terminal and is used to signal from a plurality of distributed antenna units.
The diversity transmission of selecting a plurality of more excellent distributed antenna units is conducive to avoid the descending power of distributed antenna unit limited, a kind of diversity transmitting method commonly used is to postpone transmit diversity between a plurality of distributed antenna units at present, be that each distributed antenna unit adopts different time delays that the downlink signal is postponed, so that seemed to be similar to after receiving and receive a multipath signal with fixed response time expansion and distribute by terminal is comprehensive from the signal of each distributed antenna unit, the receiver that the terminal utilization has a resolution capability of multipath fully utilizes the signal energy in each footpath (in fact from each distributed antenna unit).
But the problem that this diversity mode faces is exactly the emission how each distributed antenna unit is set to be postponed, because the mobility of terminal and the complexity of wireless channel, different terminals is different to the signal time delay of each distributed antenna unit, same terminal signal time delay to each distributed antenna unit in moving process is also changing, so in order to finish the effect of downlink delays transmit diversity, each distributed antenna unit need to be avoided launching and postpone lucky counteracting terminal to be set to the situation of the channel delay of each spaced antenna, superpose simultaneously again in end so that postpone the downstream signal of each distributed antenna unit of setting by emission, so that the diversity gain that terminal can't utilize multipath to produce.
Summary of the invention
The invention provides a kind of method of down transmission diversity, can't utilize the problem of the diversity gain that multipath produces in order to solve the terminal that exists in the prior art.
The method of the invention comprises:
Steps A: a plurality of alternative each distributed antenna unit time delay combinations are scheduled in the base station;
Step B: the base station travels through described predetermined a plurality of time delay combinations, judge whether to exist at least one time delay combinations, described time delay combinations is for each terminal in the system, postponing the composite signal that the descending diversity transmission signal for this terminal arrives after this terminal from each distributed antenna unit is distinguishable multipath signal for this terminal receiver, if when having at least one described time delay combinations, then with described time delay combinations emission time delay on each distributed antenna unit is set, and carry out the downlink delays diversity transmission, otherwise the downlink delays diversity mode of converting system is the selectivity emission of selecting Optimal Distribution formula antenna element.
Further, described steps A specifically comprises:
The time delay combinations of predetermined a plurality of alternative each distributed antenna units in base station;
According to predetermined a plurality of time delay combinations, calculate under each time delay combinations, postpone the relative time parameter that the descending diversity transmission signal for each terminal arrives this terminal from each distributed antenna unit.
Further, among the described step B, judge described time delay combinations for each terminal in the system, postponing the composite signal that the descending diversity transmission signal for this terminal arrives after this terminal from each distributed antenna unit is that the process of distinguishable multipath signal specifically comprises for this terminal receiver:
For each terminal in the system, if this terminal is for any two different distributed antenna units, the difference of its relative time parameter all is not less than the time width of a chip, and then to postpone the composite signal that the descending diversity transmission signal for this terminal arrives after this terminal from each distributed antenna unit be distinguishable multipath signal for this terminal receiver to this terminal.
Wherein, the emission delay on peak value footpath time of advent of the described relative time parameter upward signal that is this terminal to arbitrary distributed antenna unit and this distributed antenna unit with.The channel estimating that described emission delay is carried out according to the training sequence in the Time Division-Synchronous Code Division Multiple Access frame structure, the peak of measuring the footpath after the impulse response of acquisition up channel obtains.
In sum, the invention provides a kind of method of down transmission diversity, by adaptive down transmission diversity mode, can fully guarantee the gain that descending multidiameter transmit diversity mode produces.
Description of drawings
Fig. 1 is the schematic flow sheet of the described method of the embodiment of the invention.
Embodiment
Below in conjunction with accompanying drawing the embodiment of the invention is elaborated.
As shown in Figure 1, the described downlink transmitting and diversity method of the embodiment of the invention can may further comprise the steps:
Step 101: the peak value footpath A time of advent of the upward signal of each terminal in a plurality of terminals of base station measurement to each distributed antenna unit
i, i=1...N, A
iFor the upward signal of this terminal arrives peak value footpath time of advent of i the upward signal on the distributed antenna unit, N is the distributed antenna unit number that the base station is equipped with;
Wherein, peak value footpath time of advent of the upward signal of each terminal to each distributed antenna unit can be by according to the midamble (training sequence in the TD-SCDMA frame structure, be called the Midamble code) the midamble code channel estimating of carrying out, the peak that obtains to measure after the up channel impulse response footpath obtains.
Step 102: the base station pre-establishes a series of each selective distributed antenna unit time delay combinations, and time delay combinations is expressed as: D
i, i=1...N, wherein D
iIt is the emission delay on i the distributed antenna unit;
The base station travels through each predetermined time delay combinations, calculates under each combination, postpones the relative time parameter that the descending diversity transmission signal for certain terminal arrives this terminal from each distributed antenna unit.
Step 103: judge whether to exist at least a time delay combinations, this time delay combinations is designated as OptDelay, for each terminal in the system, postponing the composite signal that the descending diversity transmission signal for this terminal arrives after this terminal from each distributed antenna unit is distinguishable multipath signal for this terminal receiver, if there is at least one such time delay combinations OptDelay, then transfer step 104 to, otherwise, step 105 transferred to;
Wherein, judge for each terminal in the system that postponing the composite signal that the descending diversity transmission signal for this terminal arrives after this terminal from each distributed antenna unit is that the detailed process of distinguishable multipath signal is for this terminal receiver:
If i and j are two different distributed antenna units, D
iBe the emission delay on i the distributed antenna unit, D
iBe the emission delay on j the distributed antenna unit, N is the distributed antenna unit number that the base station is equipped with; A
iFor the upward signal of this terminal arrives i the time of advent on the distributed antenna unit, A
jFor the upward signal of this terminal arrives j the time of advent on the distributed antenna unit, then A
i+ D
iBe the to postpone the relative time parameter that the descending diversity transmission signal for this terminal arrives this terminal, A from i distributed antenna unit
j+ D
jBe the to postpone the relative time parameter that the descending diversity transmission signal for this terminal arrives this terminal from j distributed antenna unit;
For each terminal, if this terminal all satisfies for any two different distributed antenna unit i and j: | (A
i+ D
i)-(A
j+ D
j) | 〉=Tchip, i ∈ 1...N, j ∈ 1...N, and i ≠ j, wherein Tchip is the time width (781.25 nanosecond) of a chip (chip) among the TD, illustrates that it is distinguishable multipath signal for this terminal receiver that this terminal postpones the composite signal that the descending diversity transmission signal for this terminal arrives after this terminal from each distributed antenna unit.Above-mentioned algorithm steps calculates at each subframe of TD-SCDMA system (subframe), namely carries out one time above-mentioned calculation procedure take each subframe as chronomere.
Step 104: usage flag is that the combination of OptDelay arranges the emission time delay on each distributed antenna unit, and carries out the downlink delays diversity transmission;
Step 105: the downlink delays diversity mode of converting system is the selectivity emission of selecting Optimal Distribution formula antenna element.
In sum, the embodiment of the invention provides a kind of method of down transmission diversity, by adaptive down transmission diversity mode, can fully guarantee the gain that descending multidiameter transmit diversity mode produces.
The above; only for the better embodiment of the present invention, but protection scope of the present invention is not limited to this, 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 claims.
Claims (3)
1. the method for a down transmission diversity is characterized in that, comprising:
Steps A: the time delay combinations of predetermined a plurality of alternative each distributed antenna units in base station; According to predetermined a plurality of time delay combinations, calculate under each time delay combinations, postpone the relative time parameter that the descending diversity transmission signal for each terminal arrives this terminal from each distributed antenna unit;
Step B: the base station travels through described predetermined a plurality of time delay combinations, judge whether to exist at least one time delay combinations, described time delay combinations is for each terminal in the system, postponing the composite signal that the descending diversity transmission signal for this terminal arrives after this terminal from each distributed antenna unit is distinguishable multipath signal for this terminal receiver, if when having at least one described time delay combinations, then with described time delay combinations emission time delay on each distributed antenna unit is set, and carry out the downlink delays diversity transmission, otherwise the downlink delays diversity mode of converting system is the selectivity emission of selecting Optimal Distribution formula antenna element;
Among the described step B, judge that described time delay combinations is for each terminal in the system, postponing the composite signal that the descending diversity transmission signal for this terminal arrives after this terminal from each distributed antenna unit is that the process of distinguishable multipath signal specifically comprises for this terminal receiver: for each terminal the system, if this terminal is for any two different distributed antenna units, the difference of its relative time parameter all is not less than the time width of a chip, and then to postpone the composite signal that the descending diversity transmission signal for this terminal arrives after this terminal from each distributed antenna unit be distinguishable multipath signal for this terminal receiver to this terminal.
2. method according to claim 1 is characterized in that, the emission time delay on peak value footpath time of advent of the upward signal that described relative time parameter is this terminal to arbitrary distributed antenna unit and this distributed antenna unit with.
3. method according to claim 2 is characterized in that, the channel estimating that described emission time delay is carried out according to the training sequence in the Time Division-Synchronous Code Division Multiple Access frame structure, and the peak of measuring the footpath after the impulse response of acquisition up channel obtains.
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| CN 200710188029 CN101442353B (en) | 2007-11-22 | 2007-11-22 | Method for down transmission diversity |
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| CN 200710188029 CN101442353B (en) | 2007-11-22 | 2007-11-22 | Method for down transmission diversity |
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| CN101442353A CN101442353A (en) | 2009-05-27 |
| CN101442353B true CN101442353B (en) | 2013-03-20 |
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| CN106533629A (en) * | 2016-12-05 | 2017-03-22 | 珠海市魅族科技有限公司 | Switching method of delay mode, switching device, terminal and base station |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1980209A (en) * | 2005-12-05 | 2007-06-13 | 松下电器产业株式会社 | Random-cycle time-delay diversity orthogonal frequency division multiplexing transmission method |
| CN101039134A (en) * | 2007-04-19 | 2007-09-19 | 中兴通讯股份有限公司 | Method for realizing transmitter diversity using two remote RF units |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1980209A (en) * | 2005-12-05 | 2007-06-13 | 松下电器产业株式会社 | Random-cycle time-delay diversity orthogonal frequency division multiplexing transmission method |
| CN101039134A (en) * | 2007-04-19 | 2007-09-19 | 中兴通讯股份有限公司 | Method for realizing transmitter diversity using two remote RF units |
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