Summary of the invention
The object of the present invention is to provide the system and method for a kind of wireless broadband network allocated bandwidth and scheduling, SS proposes bandwidth application and BS collaborative work according to the strategy of algorithm dictates, finishes allocated bandwidth and uplink scheduling; BS is that different SS distributes priority, under the identical situation of each SS Business Stream priority, and the Business Stream of priority scheduling two-forty modulation coding mode SS, thus obtain big as far as possible throughput; Select whether to abandon data by the control of long delay more simultaneously.
This system comprises subscriber station and base station, and subscriber station comprises uplink scheduling unit and bandwidth application unit, and the base station comprises allocated bandwidth unit and descending scheduling unit, the scheduling between realization subscriber station and the base station and the interaction process of allocated bandwidth.Allocated bandwidth at uplink scheduling, the SDU to be sent that the uplink scheduling unit will receive, join the uplink scheduling formation, and to bandwidth application unit transmission bandwidth request, the bandwidth application unit is according to the qos parameter requirement, check the reasonability of bandwidth request, then send bandwidth request to the base station by checking.The allocated bandwidth unit adds bandwidth request queue with the bandwidth request that receives, the allocated bandwidth unit is to be the period treatment bandwidth request queue with the frame, the allocated bandwidth unit serves as according to distributing bandwidth with the priority of Business Stream, generate bandwidth allocation information, and send to subscriber station, thereby the uplink scheduling unit sends in scheduling on the upstream bandwidth that distributes SDU according to bandwidth allocation information after forming mac frame.At the allocated bandwidth of descending scheduling, a SDU to be sent of the Business Stream that the descending scheduling unit receives the base station joins the descending scheduling formation, and sends bandwidth request to the allocated bandwidth unit; The allocated bandwidth unit adds bandwidth request queue with the bandwidth request that receives, and is the period treatment bandwidth request queue with the frame; The allocated bandwidth unit according to priority distributes bandwidth, generates bandwidth allocation information; The descending scheduling unit is according to bandwidth allocation information, and the PDU of each Business Stream is being sent after forming mac frame in scheduling on the downlink bandwidth that distributes.
This method is to carry out the distributive operation of bandwidth with the physical frame cycle, distributes fixed-bandwidth automatically periodically for the artificial circuit class business that does not participate in dispatching in the Business Stream earlier.Behind the deduction fixed-bandwidth, the priority of other all kinds of business in the regulation Business Stream is so that distribute remaining bandwidth.Under the situation of guaranteed qos parameter priority of agreement level, make modulation coding mode participate in computing, obtain new priority, by new priority assignment remaining bandwidth.Other all kinds of business comprise real-time class business, non real-time class business and best effort class business in the Business Stream of request bandwidth allocation.Behind the deduction fixed-bandwidth, at first be all its required minimum bandwidths of real-time class traffic assignments.Bandwidth request for real-time class business, if the distribution of minimum bandwidth can not be satisfied the delay requirement in the qos parameter, SS will keep one of corresponding SDU data and preestablish the time, surpass this time-delay and then abandon these SDU data, revise the bandwidth request amount by accumulation type bandwidth request notice BS later on.This Preset Time is greater than 3 times of minimal time delay in the qos parameter.Use the descending series parameter to come to be the different bandwidth of the traffic flow assignment of different priorities to the distribution of remaining bandwidth; The argument sequence that successively decreases is determined the self adaptation adjustment according to business statistics information.Allocated bandwidth during uplink scheduling at first will require be checked the bandwidth request reasonability according to qos parameter by subscriber station, check by after just send bandwidth request to the base station, implement the step of above-mentioned distribution fixed-bandwidth again.Allocated bandwidth during descending scheduling is then directly implemented the step of above-mentioned distribution fixed-bandwidth.
The QoS that allocated bandwidth that the present invention proposes and dispatching method can be realized miscellaneous service, and can obtain bigger throughput; Algorithm is comparatively simple simultaneously, helps software/hardware and realizes, reduces equipment cost.
Embodiment
At first explanation: data are called descending by the base station to subscriber station; Be called up to the base station by subscriber station.Downlink bandwidth is distributed voluntarily by BS, and descending scheduling is finished separately by BS; Upstream bandwidth distributes by BS/SS is collaborative to be finished, and SS carries out uplink scheduling on the bandwidth of distributing.
Allocated bandwidth and scheduling relate to following components as shown in Figure 1: bandwidth of base station distribution module or title allocated bandwidth unit, base station down scheduler module or title descending scheduling unit, subscriber station bandwidth application module or claim the bandwidth application unit, subscriber station uplink scheduling module or deserve to be called capable scheduling unit.Wherein, each module can be finished various functions, the scheduling between realization subscriber station and the base station and the interaction process of allocated bandwidth, such as:
The base station down scheduler module:
Finish downlink bandwidth and distribute, generate downlink bandwidth distribution condition information so that subscriber station obtains one's own downlink data; Manage descending SDU formation; After forming mac frame, the SDU that dispatches each subscriber station Business Stream sends to physical layer block.
The bandwidth of base station distribution module:
The managing bandwidth request queue; Finishing upstream bandwidth distributes; Generate upstream bandwidth distribution condition information so that subscriber station is finished uplink scheduling.
Subscriber station bandwidth application module:
Propose the bandwidth application according to algorithm policy, rather than the upper strata need send data and just files an application.So just alleviated the processing burden of the bandwidth allocation module of base station.
Base station uplink scheduling module:
According to the upstream bandwidth distribution condition information that the base station generates, the PDU of a scheduling Business Stream sends to physical layer block.
Allocated bandwidth of the present invention and dispatching method are specific as follows.
Referring to Fig. 2, Business Stream is divided into four classes: artificial circuit class, real-time class, non real-time class, best effort class.Artificial circuit class service bandwidth demand is fixed, and in order to save the bandwidth allocation algorithm expense of BS, this class business does not produce bandwidth request, does not participate in scheduling, and the BS bandwidth allocation module is regularly distributed bandwidth for it.Other three classes Business Streams can produce bandwidth request, and the BS bandwidth allocation module is this three classes traffic assignments bandwidth on remaining bandwidth B1 after the bandwidth that deduction regularly distributes for the artificial circuit class.
All kinds of Business Stream priority differences stipulate that real-time class is higher than the non real-time class, the non real-time class is higher than best effort class; Same line of business stream also has user-defined priority; For the identical same line of business stream of user class priority, the SS of BS acquiescence two-forty modulation coding mode has higher priority.
BS is all its required minimum bandwidths of real-time class traffic assignments earlier, and remaining bandwidth B2 is according to priority distributed by real-time class business (need extra bandwidth, promptly maximum bandwidth and minimum bandwidth is poor) and non real-time class business.BS stipulates new priority according to the priority and the modulation coding mode of QoS configuration:
New priority=qos parameter priority * 32+ modulation coding mode weight
Qos parameter priority=0~7;
For guaranteed qos parameter priority influence, to its on duty last 32;
The modulation coding mode weight=
0=BPSK(CC?1/2)
1=QPSK(RS+CC/CC?1/2)
2=QPSK(RS+CC/CC?3/4)
3=16-QAM(RS+CC/CC?1/2)
4=16-QAM(RS+CC/CC?3/4)
5=64-QAM(RS+CC/CC?2/3)
6=64-QAM(RS+CC/CC?3/4)
7=QPSK(BTC?1/2)
8=QPSK(BTC?3/4)
9=16-QAM(BTC?3/5)
10=16-QAM(BTC?4/5)
11=64-QAM(BTC?2/3)
12=64-QAM(BTC?5/6)
13=QPSK(CTC?1/2)
14=QPSK(CTC?2/3)
15=QPSK(CTC?3/4)
16=16-QAM(CTC?1/2)
17=16-QAM(CTC?3/4)
18=64-QAM(CTC?2/3)
19=64-QAM(CTC?3/4)
By the professional and professional ordering of non real-time class of new priority to all real-time classes.According to statistics descending series a[N is arranged];
Bandwidth=the min of i traffic assignments (B2*a[i], the maximum bandwidth of QoS regulation)
Remaining bandwidth B3 distributes to the best effort class business, according to statistics descending series b[N is arranged]:
1. calculate new top grade=qos parameter priority * 32+ modulation coding mode weight, ordering
2.B=B3
3. be i best effort class traffic flow assignment bandwidth=B*b[i],
4. upgrade remaining bandwidth B, change 3, otherwise finish as B>0.
(annotate: N, i are natural number, a[N], b[N] be fractional fixed point)
Use the descending series parameter to come to be the different bandwidth of the traffic flow assignment of different priorities to the distribution of remaining bandwidth, the argument sequence that successively decreases is determined the self adaptation adjustment according to business statistics information.Use the descending series parameter to ensure to the different bandwidth of traffic flow assignment of different priorities, avoided complicated calculating, whole algorithm simply is easy to realize.
BS carries out bandwidth allocation algorithm with the physical frame cycle, if the data of certain bandwidth request next frame can hold from bandwidth request queue this bandwidth request of deletion, otherwise, revise the data volume of this bandwidth request.For real-time class business, if can not satisfy delay requirement by upstream bandwidth distribution and scheduling, SS will keep one of corresponding SDU data and preestablish the time (general greater than 3 times of the minimal time delays in the qos parameter), surpass this time-delay and then abandon these SDU data, revise the bandwidth request amount by accumulation type bandwidth request notice BS later on.That is to say, for real-time class business, if minimum bandwidth allocation can not satisfy delay requirement, just SS sets up longer timing whether to determine the discarded part divided data.This is because for real-time class business, when network is busy, may get minimum bandwidth, if bigger packet bandwidth on demand may not satisfy delay requirement, set up more long delay timer, avoid the accidental busy obliterated data of network, continue when busy at network simultaneously, the discarded part divided data is because it is meaningless to real-time class business to surpass the data of long delay more.
Referring to Fig. 3, the up SDU formation of SS uplink scheduling module management, receive that a SDU promptly sends a bandwidth request to bandwidth application module, bandwidth application module is according to the qos parameter requirement, check the reasonability of this request, send bandwidth application (being the strategy proposition bandwidth request of SS) to BS according to algorithm dictates by checking then.So just alleviate the burden of BS bandwidth allocation module, improved the efficient of its allocated bandwidth.
Uplink scheduling and allocated bandwidth are as follows:
SS receives a MAC SDU to be sent;
SS uplink scheduling module adds the uplink scheduling formation with MAC SDU to be sent, sends a bandwidth request to bandwidth application module;
SS bandwidth application module is checked the reasonability of this request according to the qos parameter requirement, then sends the bandwidth application to BS by checking;
The BS bandwidth allocation module adds bandwidth request queue with the bandwidth request of receiving;
The BS bandwidth allocation module is the period treatment bandwidth request queue with the frame;
The BS bandwidth allocation module generates upstream bandwidth assignment information (such as realizing by the bandwidth allocation methods of describing before and distributing bandwidth), sends to SS:
SS uplink scheduling module sends SDU scheduling after forming mac frame on the upstream bandwidth that distributes of each Business Stream.
Thereby subscriber station is not data to be arranged with regard to bandwidth on demand, proposes the bandwidth application but handle the back by analysis.
Descending scheduling and allocated bandwidth are as follows:
BS receives a MAC SDU to be sent;
BS descending scheduling module adds the descending scheduling formation with MAC SDU to be sent, sends a bandwidth request to bandwidth application module;
The BS bandwidth allocation module adds bandwidth request queue with the bandwidth request of receiving;
The BS bandwidth allocation module is the period treatment bandwidth request queue with the physical frame;
The BS bandwidth allocation module generates downlink bandwidth assignment information (realize and distribute bandwidth such as the bandwidth allocation methods by before);
BS descending scheduling module sends in scheduling on the downlink bandwidth that distributes the SDU of each Business Stream after forming mac frame.
Among the present invention,, alleviated the efficient that scheduling and bandwidth allocation algorithm are handled because artificial circuit class business does not participate in scheduling; Modulation coding mode participates in priority and calculates, and makes the subscriber station with higher modulation coding may obtain big bandwidth, can improve bandwidth availability ratio and network throughput; Subscriber station proposes the bandwidth application by the strategy of algorithm dictates, has alleviated the computation burden of BS bandwidth allocation module, has improved the efficient of its allocated bandwidth.The method that this class special operational maintaining channel is set up among the present invention, when giving the traffic flow assignment bandwidth of according to priority arranging, priority is high more, the bandwidth that may get is big more, it uses the descending series parameter to come to the different bandwidth of the traffic flow assignment of different priorities, avoid complicated calculating, guaranteed fairness simultaneously.