CN101043265A - Method for realizing multimedia broadcasting and multicasting service data synchronized transmission - Google Patents

Abstract

The invention provides a method of realizing multimedia broadcasting and group broadcasting operation transmission in-phase, the method includes: data is marked with time when generating multimedia broadcasting and group broadcasting operation data, and deciding the transmission time of empty port according to the time mark; calculating the data transmission frame number of areola based on the transmission time of empty port. The implement of the invention can realize the synchronization transmission of MBMS operation in an areola on condition that base station does not support node synchronization.

Description

A kind of method that realizes multimedia broadcasting and multi-cast business data synchronized transmission

Technical field

The present invention relates to multimedia broadcasting and multicast service (MBMS) field, relate to a kind of method that realizes multimedia broadcasting and multi-cast business data synchronized transmission concretely.

Background technology

In traditional mobile network, cell broadcaste service (Cell Broadcast Service) allows low bit rate data to share broadcast channel to all users' transmissions by the sub-district, belongs to information series business.Now, people no longer are satisfied with phone and messaging service to the demand of mobile communication, and along with the fast development of the Internet, a large amount of multimedia services emerge.In order effectively to utilize mobile network resource, the WCDMA global standardsization organize 3GPP (3rd Generation Partnership Project) to propose multimedia broadcasting and multicast service (MBMS:Multimedia Broadcast and Multicast Service), in the mobile network, provide a data source sends point from data to a plurality of users to multiple spot (PTM:Point-to-Multi-point) business, the realization Internet resources are shared, improve utilization rate of network resource, especially interface-free resources.The MBMS of redetermination can not only realize the classes of messages multicast and the broadcasting of plain text low rate in 3GPPRelease 6 versions, and can also realize the multicast and the broadcasting of high-speed multimedia business, and this has complied with the trend of following mobile data development undoubtedly.

When the MBMS business when eating dishes without rice or wine to adopt the PTM carrying, can support neighbor cell the same MBMS business soft merging and select to merge when cell set (neighbor cell belong to same), obtain more performance.When using soft merging, the maximum delay difference that the identical data of neighbor cell arrives mobile phone must satisfy certain limitation; When use to select merging, merge window and limited by mobile phone capacity, this also the identical data of the indirect request neighbor cell delay inequality that arrives mobile phone must satisfy certain limitation.Merge for supporting soft merging and selecting, the delay inequality that network side should dwindle the identical data arrival mobile phone of neighbor cell as far as possible realizes as far as possible that promptly the MBMS data sync sends.

3GPP proposes in agreement 25.402 V630, can arrive the delay inequality of mobile phone based on the identical data of node Synchronization Control neighbor cell.Its basic thought is as follows:

(1) and base station (NodeB) to carry out node synchronous, obtain the deviation of base station frame number BFN (NodeB Frame Number) and base station controller frame number RFN (RNC Frame Number) according to the synchronous result of node.

(2) according to deviation (Offset) and the channel parameter setting (multiplexing auxiliary publish control physical channel deviation of frequency division multiple access (FDD SCCPCH Offset) and FDD SCCPCH Frame Offset) of BFN and RFN, the identical data of control neighbor cell arrives the delay inequality of mobile phone.

But as above method can't not used when support node is synchronous in the base station.The base station of part manufacturer not support node is synchronous, also just can't realize sending based on the synchronous MBMS data sync of node.Transport channel synchronization is that the base station of all manufacturers all must be supported, if base station controller (RNC:Radio Network Controller) can realize that the MBMS data synchronization sends, and just can avoid the butt joint risk with different vendor's base station equipment based on transport channel synchronization.

Summary of the invention

The object of the present invention is to provide a kind of method that realizes multimedia broadcasting and multi-cast business data synchronized transmission, calculate the synchronous Connection Frame Number (CFN:Connection Frame Number) of the transmitting time of eating dishes without rice or wine of the MBMS data of sening as an envoy to based on the transport channel synchronization result, thereby the data sync that realizes different districts sends.

To achieve these goals, the realization multimedia broadcasting of the embodiment of the invention and the method for multi-cast business data synchronized transmission comprise the steps:

When generating multimedia broadcasting and multi-cast business data, data are beaten timestamp, and the delivery time of eating dishes without rice or wine according to this timestamp decision;

The data transmission Connection Frame Number of delivery time of eating dishes without rice or wine according to decision based on the transport channel synchronization calculation plot.

By embodiments of the invention, can not realize the synchronized transmission of MBMS business datum each sub-district in a cell set under the synchronous situation of support node at base station (NodeB).

Description of drawings

Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, does not constitute limitation of the invention.In the accompanying drawings:

Fig. 1 realizes the principle schematic that the MBMS data sync sends in the embodiment of the invention;

Fig. 2 makes the schematic flow sheet of the synchronous Connection Frame Number CFN of the delivery time of eating dishes without rice or wine of MBMS data for calculating of the present invention.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, specific embodiments of the invention are elaborated below in conjunction with accompanying drawing.At this, illustrative examples of the present invention and explanation thereof are used to explain the present invention, but not as a limitation of the invention.

In transport channel synchronization, base station controller (RNC) sends down-going synchronous control frame (DLSYNCHRONISATION control frame) and gives base station (NodeB), has Connection Frame Number CFN in the frame.After NodeB receives the down-going synchronous frame, use up synchronous control frame (UL SYNCHRONISATIONcontrol frame) response at once, have CFN and corresponding due in (TOA) in the frame.

RNC comprises Connection Frame Number (CFN) in issuing the Frame of base station, the base station just can obtain the transmitting time of eating dishes without rice or wine of these data by CFN.The data sync that realizes different districts sends, and will realize that just different districts will be synchronously in the transmitting time of eating dishes without rice or wine.Because CFN is not the relating to parameters of absolute time and each sub-district, even the transmitting time of eating dishes without rice or wine is identical, the CFN of different districts also may be different.Therefore will realize that different districts is synchronous in the transmitting time of eating dishes without rice or wine, in fact be exactly that the data of calculating each sub-district send CFN, makes in the actual transmitting time of eating dishes without rice or wine synchronous.

For the data sync that realizes different districts sends, can when generating the MBMS data, beat timestamp t to data _Timestamp, the delivery time of all eating dishes without rice or wine according to this timestamp decision in all sub-districts.RNC can determine a parameter Δ according to the delay character between RNC and all NodeB, and each sub-district determines the data of this sub-district to send CFN (Connection Frame Number) according to the situation of this timestamp and this sub-district, is implemented in t _TimestampSend data near the moment of+Δ, reach the purpose that data sync sends.In the method, t _TimestampGet the current RFN (precision is got 1ms) when generating the MBMS data; The value of Δ (precision is got 1ms) will guarantee in most cases, and each sub-district has time enough to send data (this moment part sub-district need in the data of RNC buffer memory certain hour).

In transport channel synchronization, suppose that RNC is at moment t _SendSend data, NodeB will

Constantly receive data, and NodeB receives that the time difference that data and data send is TOA+TOAWE+T _ProcWherein TOA is due in (Time Of Arrival), TOA WE represents due in window end point (Time Of Arrival Window Endpoint), and RTT (Round Trip Time) is the loopback delay (supposing that here the uplink and downlink loopback delay is identical) of RNC and NodeB, T _ProcIn processing time before expression eats dishes without rice or wine to send, the detailed description of each variable can be referring to 3GPP agreement 25.402.Thus, can calculate, when RNC at moment t _SendWhen sending downlink data frame, these data at the delivery time of eating dishes without rice or wine are:

$t_{\mathrm{send}}+\frac{\mathrm{<figure-callout\; id="2"\; label="RTT"\; filenames="A20071009880500111.png,A20071009880500121.png"\; state="\{\{state\}\}">RTT</figure-callout>}}{2}+\mathrm{TOA}+\mathrm{TOAWE}+T_{\mathrm{proc}}---\left(1\right)$

Just can draw the computing formula of Connection Frame Number CFN based on transport channel synchronization and formula (1).That detailed process illustrates is following (as shown in Figure 2, below the unit of all variablees be ms, except the special instruction):

(1) calculate frame deviation Off and Loop Round Trip Time RTT between RFN and the BFN based on following transport channel synchronization result:

At moment RFN ₀Send the transmission channel synchronization frame of CFN=0, at RFN ₁Constantly receive and carry due in TOA in this uplink synchronous frame by corresponding uplink synchronous frame ₀, then

Off＝(RFN ₀+TOA ₀)％CFN_MAX； (2)

RTT＝(RFN ₁-RFN ₀)％RFN_MAX； (3)

Wherein, CFN_MAX gets 2560 (CFN_MAX for be the scope of the CFN of unit with ms), and RFN_MAX is 40960 (RFN_MAX is that RFN is the scope of unit with ms).% represents the complementation computing, and the result is non-negative.More than calculate hypothesis RTT less than RFN_MAX, and ignore the processing time of NodeB transmission channel synchronization frame.

By the description of front as can be known, realize that the data sync of different districts sends, should guarantee the different districts data at the delivery time of eating dishes without rice or wine at t _TimestampNear+the Δ, promptly $t_{\mathrm{send}}+\frac{\mathrm{<figure-callout\; id="2"\; label="RTT"\; filenames="A20071009880500111.png,A20071009880500121.png"\; state="\{\{state\}\}">RTT</figure-callout>}}{2}+\mathrm{TOA}+\mathrm{TOAWE}+T_{\mathrm{proc}}=t_{\mathrm{timestamp}}+\mathrm{\&Delta;},$

$t_{\mathrm{send}}=t_{\mathrm{timestamp}}+\mathrm{\&Delta;}-(\frac{\mathrm{<figure-callout\; id="2"\; label="RTT"\; filenames="A20071009880500111.png,A20071009880500121.png"\; state="\{\{state\}\}">RTT</figure-callout>}}{2}+\mathrm{TOA}+\mathrm{TOAWE}+T_{\mathrm{proc}}).$

RNC is at RFN ₀The CFN that the moment sends ₀=0 transport channel synchronization downlink data frame at the delivery time of eating dishes without rice or wine is:

This constantly might not be at t _TimestampNear+the Δ, and may be at t _TimsestampSend before or after+the Δ.

Therefore, realize that data are synchronous in the transmitting time of eating dishes without rice or wine, should adjust the time that RNC sends Frame, with guarantee Frame at the delivery time of eating dishes without rice or wine at t _TimestampNear+the Δ, the time quantum that should adjust is:

$t_{\mathrm{send}}-{\mathrm{RFN}}_0=t_{\mathrm{timestamp}}+\mathrm{\&Delta;}-(\frac{\mathrm{<figure-callout\; id="2"\; label="RTT"\; filenames="A20071009880500111.png,A20071009880500121.png"\; state="\{\{state\}\}">RTT</figure-callout>}}{2}+\mathrm{TOA}+\mathrm{TOAWE}+T_{\mathrm{proc}})-{\mathrm{RFN}}_0;$ Can obtain through arrangement:

$t_{\mathrm{send}}-{\mathrm{RFN}}_0=t_{\mathrm{timestamp}}-\mathrm{Off}+\mathrm{\&Delta;}-(\frac{\mathrm{<figure-callout\; id="2"\; label="RTT"\; filenames="A20071009880500111.png,A20071009880500121.png"\; state="\{\{state\}\}">RTT</figure-callout>}}{2}+\mathrm{TOAWE}+T_{\mathrm{proc}});$

Set one and adjust variable $t_{\mathrm{adjust}}=\mathrm{\&Delta;}-(\frac{\mathrm{<figure-callout\; id="2"\; label="RTT"\; filenames="A20071009880500111.png,A20071009880500121.png"\; state="\{\{state\}\}">RTT</figure-callout>}}{2}+\mathrm{TOAWE}+T_{\mathrm{proc}}),$ Then

t _sed-RFN ₀＝t _timestamp-Off+t _adjust；

The CFN that data sync that thus can accomplished sub-district sends:

CFN _coarse＝(t _timestamp-Off+t _adjust)％CFN_MAX。

Just can calculate the Connection Frame Number that needs by following step.

(2) calculate adjustment variable t _Adjust:

Utilize the RTT that obtains in the step (1) just can calculate and adjust variable t according to following formula _Adjust:

$t_{\mathrm{adjust}}=\mathrm{\&Delta;}-\frac{\mathrm{RTT}}{2}-\mathrm{TOAWE}-T_{\mathrm{proc}};---\left(4\right)$

In the following formula, Δ is given parameter, and the value of Δ will guarantee for normal cell, t _AdjustBe (best t for safety, just _AdjustGreater than certain positive threshold value), and t _AdjustLess than CFN_MAX.Simultaneously, Δ can not surpass CFN_MAX, otherwise time delay may reach CFN_MAX between different districts.If choosing is less than suitable Δ, this algorithm is difficult to use.T in the formula (2) _ProcDepend on equipment vendor/type of service, desirable empirical value.If the T of each sub-district _ProcDifference is too big, and algorithm performance can descend.In addition, aforementioned calculation supposes that also the chain-circuit time delay of up-downgoing is identical.

(3) calculate CFN _Coarse:

The timestamp t of record during according to generation MBMS business _Timestamp, frame deviation Off and time between RFN and the BFN adjusts variable t _AdjustThe data that just can tentatively obtain the sub-district send Connection Frame Number CFN _Coarse:

CFN _coarse＝(t _timestamp-Off+t _adjust)％CFN_MAX； (5)

This is a PRELIMINARY RESULTS.

(4) with CFN _CoarseSnap to the CFN border, just can obtain final Connection Frame Number CFN:

For the Connection Frame Number CFN that guarantees finally to obtain on Transmission Time Interval (TTI:Transmission Timing Interval) border, can convert by following formula again:

CFN＝(CFN′％CFN_MAX)/10 (7)

The CFN that utilizes formula (6), (7) to calculate is an integer, and span is [0,255], is last result of calculation.

The data of each sub-district of calculating according to as above formula send CFN, just can realize that different districts is synchronous in the data transmitting time of eating dishes without rice or wine.Base station controller RNC is sent in the Frame of base station can comprise the described CFN that calculates, and can determine that according to this CFN base station controller sends the moment of downlink data frame.

When using the above-mentioned algorithm of present embodiment, at first carry out the 1st, 2 steps, obtain algorithm parameter, receive the MBMS business datum afterwards at every turn, carry out the 3rd, 4 steps and obtain the CFN that data send.Because the 1st, 2 steps can be periodically carried out in the clock drift of RNC and NodeB, upgrade relevant parameter.

Fig. 1 is that the realization MBMS data sync of one embodiment of the invention sends schematic diagram, and wherein RNC CFN represents the CFN that RNC carries when sending Frame to NodeB, and NodeB CFN represents the CFN of NodeB correspondence when eating dishes without rice or wine to send Frame.According to Fig. 1, the roughly flow process that obtains the data transmission CFN of each sub-district in the present embodiment is: when generating the MBMS data data are beaten timestamp t _Timestamp, and with t _Timestamp(this time is the RNC time) is converted to the NodeB time, adds then $t_{\mathrm{adjust}}=\mathrm{\&Delta;}-\frac{\mathrm{RTT}}{2}-\mathrm{TOAWE}-T_{\mathrm{proc}},$ And snap to the CFN border, just obtain Connection Frame Number CFN.

Calculating t _AdjustStep in, if the T of each sub-district _ProcDifference is too big, and algorithm performance can descend.For alleviating T _ProcTo the influence of algorithm performance, (for example, Common transport channel is set up response: COMMON TRANSPORTCHANNEL SETUP RESPONSE) T can to allow the base station pass through NodeB Application Part (NBAP:NodeBApplication Part) signaling _ProcInform RNC, so just can solve the T of different districts _ProcThe different errors of calculation of being introduced.If NodeB passes through the NBAP signaling with T _ProcInform RNC, then need to revise agreement 25.433, in corresponding NBAP signaling (for example COMMON TRANSPORT CHANNEL SETUP RESPONSE), increase and carry T _ProcNew cell.

By as above embodiment, can not realize the synchronized transmission of MBMS business datum each sub-district in a cell set, the delay inequality requirement of satisfying soft merging and selecting to merge under the synchronous situation of support node at NodeB.

According to the as above algorithm of embodiment, the transmitting time difference of each sub-district is a TTI to the maximum and (does not consider T _ProcError.That is to say the T of each sub-district _ProcIdentical or NodeB passes through the NBAP signaling T _ProcInform RNC), if T _ProcError (in most cases satisfy) in a TTI, the transmitting time difference of each sub-district is two TTI to the maximum.

Above embodiment only is used to illustrate the present invention, but not is used to limit the present invention.Within the spirit and principles in the present invention all, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (7)

1. a method that realizes multimedia broadcasting and multi-cast business data synchronized transmission is characterized in that comprising the steps:

When generating multimedia broadcasting and multi-cast business data, data are beaten timestamp, and the delivery time of eating dishes without rice or wine according to this timestamp decision;

The data transmission Connection Frame Number of delivery time of eating dishes without rice or wine according to decision based on the transport channel synchronization calculation plot.

2. method according to claim 1 is characterized in that:

The data of sub-district send Connection Frame Number and satisfy following formula:

CFN _Coarse=(t _Timestamp-Off+t _Adjust) %CFN_MAX; Wherein

Off＝(RFN ₀+TOA ₀)％CFN_MAX；

RTT＝(RFN ₁-RFN ₀)％RFN_MAX；

$t_{\mathrm{adjust}}=\mathrm{\&Delta;}-\frac{\mathrm{RTT}}{2}-\mathrm{TOAWE}-T_{\mathrm{proc}};$

In the above-mentioned formula, the unit of each variable is a millisecond, RFN ₀For sending the base station controller RNC frame number that Connection Frame Number is 0 transmission channel synchronization frame, RFN ₁For receiving the RNC frame number of uplink synchronous frame, TOA ₀Be the due in that carries in the described uplink synchronous frame, RFN_MAX is for being the maximum occurrences of the RNC frame number of unit with the millisecond; Δ is for generating multimedia broadcasting and the multi-cast business data time up to the delivery time of eating dishes without rice or wine; RTT is the loopback delay of base station controller and base station, and described RTT is less than RFN_MAX; TOAWE is the window terminal point time of advent; T _ProcSend the preceding processing time for eating dishes without rice or wine; t _TimestampBe the timestamp that when generating multimedia broadcasting and multi-cast business data, writes down; CFN _CoarseData transmission Connection Frame Number for the sub-district; CFN_MAX is for being the maximum occurrences of the Connection Frame Number CFN of unit with the millisecond.

3. method according to claim 1 and 2 is characterized in that also comprising, the Connection Frame Number that obtains is arrived the Transmission Time Interval border to it, to obtain the Connection Frame Number on Transmission Time Interval TTI border.

4. method according to claim 3 is characterized in that:

Described Connection Frame Number on Transmission Time Interval TTI border satisfies following formula:

CFN=(CFN ' %CFN_MAX)/10; Wherein,

CFN is the integer of span in [0,255].

5. method according to claim 2 is characterized in that: described T _ProcGive RNC by the base station by base station application part NBAP signaling.

6. method according to claim 2 is characterized in that: described Δ determines that according to the delay character between RNC and the base station its value is no more than CFN_MAX; Described t _AdjustFor just, and less than CFN_MAX.

7. method according to claim 2 is characterized in that also comprising: be updated periodically Off, RTT and t according to respective formula _Adjust

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