KR20000015682A - Wireless atm communication system - Google Patents

Abstract

PURPOSE: A communication system is provided to transmit a data while effectively satisfy various service requirements in each terminal of high speed wireless communication system. CONSTITUTION: The system comprises an access point, at least one wireless terminal, and a media access controlling (MAC) means for controlling ATM (Asynchronous transfer mode) data transmitting operation between the access point and the wireless terminal through a wireless link which uses a wireless ATM MAC protocol. A transmitting frame used in the wireless ATM MAC protocol is formed into the order of a frame header, an up-link field for transmitting an up-link from the access point to the wireless terminal and a down-link field for transmitting a down-link from the wireless terminal to the access point. The boundary between the up-link field and the down-link field is variable. Thereby, a frame overhead of the transmitting frame is minimized by an effective bust structure, and a scheduling time of the access point is sufficiently secured.

Description

Wireless ATM Communication System

The present invention relates to a wireless communication system, and more particularly, to a medium access control (MAC) protocol and a medium access control (MAC) frame structure in a wireless asynchronous transmission mode (ATM) system.

The Media Access Control (MAC) protocol in the wireless asynchronous transfer mode (hereinafter referred to as ATM) is a wireless communication method for the statistical multiplexing function pursued by ATM for independently distributed mobile terminals. It serves to expand through the media. The MAC protocol must satisfy the service requirements such as bandwidth requirements, transmission delay time, and cell loss, which are dynamically changed according to various service characteristics, and provide an access environment that can efficiently and efficiently use resources for distributed mobile terminals. Must be provided.

To understand this, slot allocation in a transmission frame guarantees the quality of service (QoS) of each traffic with a minimum bandwidth, and must be designed in consideration of the simplicity of the slot allocation procedure. The slot allocation algorithm considered is needed. Constant Bit Rate (hereinafter referred to as CBR) traffic, which can predict the period of traffic generation, does not require a separate complicated dynamic slot allocation algorithm by applying periodic polling or fixed slot allocation. On the other hand, for variable bit rate (hereinafter referred to as VBR) traffic, optimal slot allocation must be performed in consideration of instantaneous fluctuations in the traffic generation rate and QoS requirements to maximize the statistical multiplexing gain in the wireless section. Therefore, a dynamic parameter (hereinafter referred to as DP) should be transmitted to reflect the instantaneous traffic change of the terminal. The DP details necessary for scheduling should be simplified as much as possible to maximize the transmission efficiency in the radio access section, and the DP transmission scheme that can reflect the time-varying slot requirements in a timely manner should also be considered. The factor that may cause DP storage delay may be caused when a packet is transmitted in a competitive manner through a slot designated in the uplink when the DP is piggybacked due to contention delay time and in-band signaling. The slot assignment of the uplink is not made to a specific terminal and thus can be largely classified as a case of losing a chance of DP transmission. On the other hand, non-real time VBR (Nrt-VBR), Available Bit Rate (ABR), or Unspecified Bit Rate (UBR) traffic, where the requirements for latency are not stringent, can be used in a competitive or non-competitive manner for the remaining slots after slot allocation. Can share

In addition, the MAC protocol should maximize bandwidth efficiency by considering an efficient slot map method for minimizing frame overhead and a burst structure for transmitting multiple slots allocated to one terminal in one continuous unit.

In general, the conventional transport frame has the following problems. After the frame header of the transport frame, the frame is configured in the order of Downlink and Uplink. An AP may determine slot allocation of another frame only after receiving a slot allocation request in uplink. At this time, since the slot allocation decision should be put in the frame header immediately after the uplink, the calculation time is very small.

In addition, by performing all determinations related to slot allocation in the AP, a problem arises in that the AP is heavily loaded. Especially for CBR traffic, data is generated at a fixed bit rate. Not assigning this traffic to fixed slots increases hardware complexity and delay variance.

It piggybacks the DP on the data part and if there is no data to send, it sends the DP in a competitive manner. Sending a DP in a competitive manner has difficulty in guaranteeing service QoS.

An object of the present invention is to provide a wireless ATM communication system using a transmission frame capable of transmitting data while efficiently satisfying various service requirements of each terminal in a high-speed wireless transmission system.

FIG. 1 illustrates a transmission frame composed of downlink and uplink after a frame header.

2 shows a transmission frame configured in the order of uplink and downlink after the frame header.

3 shows a frame structure in the C-FD ³ R MAC protocol according to the present invention.

4 is a diagram for explaining dynamic slot adjustment for CBR traffic in a SYNC period.

5 shows a structure of an uplink burst header.

FIG. 6 is a diagram for explaining an example of deterministic scheduling based on remaining time.

7 is a view for explaining the relationship between the inter-arrival interval of the VC and the CTD.

8 illustrates a functional block of an access point (AP) for processing and generating a transport frame, including a medium access control means.

9 illustrates functional blocks of a wireless terminal (WT) for processing and generating transport frames, including media access control means.

Wireless ATM system according to the present invention for solving the above technical problem, the base station (AP); At least one wireless terminal; And medium access control means for controlling ATM data transmission between the base station and at least one wireless terminal through a wireless link using a predetermined wireless ATM MAC protocol. The frame has a frame structure consisting of a frame header, an uplink field for uplink transmission from the base station to the radio terminal, and a downlink field for downlink transmission from the radio terminal to the base station.

A boundary between the uplink field and the downlink field is variable, and the uplink field includes a contention field for transmitting a call setup and release signaling message; A sync field to which a slot of a fixed time band is allocated; And a reserved field for allocating a slot by request, wherein the downlink field includes a sync field for allocating a slot of a fixed time band; And a reserved field for allocating a slot by request.

In the uplink field, the synchronization field is located in front of the reservation field, and in the downlink field, the reservation field is preferably located in front of the synchronization field.

The sync field is for CBR traffic, the reserved field is for rt-VBR, nrt-VBR, ABR and UBR traffic, and the sync field and reserved field are bursts that are slots or aggregations of slots allocated to the wireless terminal. It is preferably made of.

The frame header includes a network ID, a base station ID, link synchronization information, a burst map indicating the number of terminals served in a reserved field, and a slot allocation result.

The link synchronization information includes uplink synchronization information and downlink synchronization information for synchronizing uplink and downlink synchronization when a call is released or added, and the uplink synchronization information and the downlink synchronization information indicate a reference position on a frame. It is preferably composed of a reference offset and a shift value representing the number of slots in the burst in which the call is released or added.

The burst map is composed of a terminal ID, an uplink map and a downlink map,

The uplink map and the downlink map preferably consist of an offset indicating a position in a frame and the number of slots allocated to a wireless terminal.

The burst includes at least a preamble and a burst header, and the burst header of the reserved field has a network ID, a base station ID, a wireless terminal ID, the number of slots allocated in the current frame, and rt-VBR traffic in the wireless terminal. It is preferable to include a dynamic parameter map (DP Map) indicating a dynamic parameter set of the virtual channels (VC) and a response map (ACK Map) for responding to receiving data transmitted in the downlink.

The DP map preferably includes the traffic class information for the VBR, the remaining time in the frame and the required number of slots, and the traffic class information and the number of cells in the buffer for the ABR and UBR.

The ACK map includes a mobile virtual channel identifier (MVCI) and response information (ACK Information), and slot or burst allocation in a reserved field is preferentially assigned to rt-VBR to improve QoS of rt-VBR. It is desirable to ensure.

Slot or burst allocation in the reserved field is determined by weighted round robin for nrt-VBR, ABR, and UBR traffic, and DP transmission is done by piggy-backing, and uplink to specific terminals. In case slot transmission is lost due to slot allocation failure, the slot allocation is performed using predicted residual time to deliver rt-VBR within the required time, and the burst piggy-backing the DP In case of a loss in a slot, slot allocation is preferably performed based on a previously received DP.

In the instantaneous traffic, in order to guarantee the QoS of the corresponding virtual channel (VC) when the radio terminal is allocated fewer slots than necessary slots, cell discarding or implicit UPC control is used, and uplink slot allocation scheduling is performed by a base station. And distributed scheduling respectively performed in the wireless terminal.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. The wireless communication system according to the present invention includes a base station corresponding to an access point (AP), at least one wireless terminal (WT), and at least one wireless terminal through a wireless link using a wireless ATM MAC protocol. Medium access control means for controlling the ATM data transmission between.

The basic transport frame structure used in the wireless ATM MAC protocol consists of fixed time division slots. The entire frame is divided into an uplink field and its boundary adopts an adaptive time division duplexing (ATDD) scheme. Each link field is basically divided into a synchronization field and a reservation field. The head of the frame is composed of a preamble and a frame header, followed by an uplink and a downlink. A scheduling time limit, which is an allowable time, for an uplink scheduler of an AP to allocate an uplink slot of a next transmission frame based on each DP information obtained through uplink of a current transmission frame. In consideration of the bounds), as shown in FIG. 1, when configured in the order of downlink and uplink after the frame header, the AP adds up to the guard time and the preamble slot time based on DP information obtained from the uplink of the current frame. After uplink scheduling is completed, slot allocation information may be notified in the next frame header. Of course, in the existing frame structure, the scheduling time-bound can be extended to some extent by arranging competition slots at the end of the frame, but considering the actual system, it is not a complete solution.

Therefore, as shown in FIG. 2, when the uplink and downlink are configured after the frame header, the scheduling time-bound becomes the number of msec which is the sum of the downlink interval, the guard time, and the preamble slot time. I can guarantee it enough. Therefore, the proposed transmission frame consists of preamble, frame header, uplink and downlink.

The uplink consists of a fixed length contention field for transmission of call establishment / release signaling messages, a synchronization field for CBR traffic, and a reservation field for rt-VBR, nrt-VBR, ABR, and UBR traffic. Similarly, the downlink is composed of a synchronization field and a reservation field except for a competition field.

As shown in FIG. 3, the frame header of the frame is a terminal that is serviced in not only Network ID and AP ID but also information for DTDM (Dynamic TDM) in uplink and downlink sync fields (Sync U / L information, Sync D / L information) # Of terminal in reserved field, and burst maps per terminal in the reserved field and the CRC.

Other information that may be selectively included may include the status information of the radio section (eg, the load state of the radio section), a call establishment / release message (broadcast) sent from the AP to the WT, and an ACK for the signaling message.

Information for DTDM in Uplink Synchronization Field Sync U / L information consists of a reference offset and a shift value (−) (in slot). This is used as shown in FIG. 4 for the dynamic TDM scheme for maintaining a sync field when adding a new call and releasing an existing call in a sync field. Based on the state of FIG. 4 (a), FIG. 4 (b) is a case where a new call is added, and when a new call is added, the uplink sync field is continuously extended backward. When the call using slots 11-16 is released as shown in FIG. 4 (c), the Sync U / L information (11, 5) value is broadcast through the frame header. After the 11th slot, the WTs allocated to the sync slot reduce their sync slot by 5 slots. Similarly, Sync D / L information has the same structure, but when the new call is added, it is extended forward and the variation is positive. This is because the downlink maintains synchronization with respect to the beginning of the frame with respect to the end of the frame.

Burst Maps exist as many as the number of terminals serviced in the reserved field. One burst map consists of a WT ID, a U / L map, and a D / L map. One U / L map or D / L map consists of an offset and a length in a frame.

3. Burst structure

The burst has a structure as shown in FIG. At the beginning of the burst is a 0.5 slot long preamble and a 0.5 slot long burst header. The burst header includes a Net ID, an AP ID, and a WT ID. The burst header includes a # of assigned slots, a DP map, an ACK map, and a CRC. The DP map is DP sets of VCs having the characteristics of rt-VBR traffic in the terminal, and each DP is composed of a residual frame time (in frame) and # of required slots.

The ACK map is a set of ACKs for data transmitted in downlink, and each ACK consists of MVCI and ACK information capable of distinguishing VC.

The data burst can be further divided into a sync burst in the sync field and a reserved burst in the reserved field. They have the same structure but the Sync burst is characterized by the absence of a DP map and ACK map in the burst header.

The slots constituting the burst are the same as the 64 byte wireless ATM cell as the basic transmission unit in the radio access plane.

4. Frame Period (Length)

The frame period should be smaller than the smallest CTD among the CTDmax of each service. This is a requirement to satisfy the CTD of all services.

In the MAC protocol, it is assumed that all CBR traffic is packed in an ATM cell by frame period and transmitted in synchronous mode. In the case of low CBR traffic, if the frame period is too short, the padding becomes large when packed into an ATM cell, thereby reducing resource efficiency. In this respect, the longer the frame period is, the better.

Frame cycle 1 msec 3 msec 5 msec 10 msec Bytes / cell 8 24 40 80

In addition, when the frame period is long, a relatively power saving effect can be obtained. For example, if a terminal using four slots on the uplink and downlink in a 200-slot period uses a frame of 100 slots in length and uses a frame of 200 slots in length, a 200-slot flami is used. If it is assumed that the frame header portion occupies four slots, the average sleep time of the terminal is 63 slots. On the other hand, if a frame having a length of 100 slots is used, assuming that the frame header part occupies two slots, the average sleep time of the terminal is 31 slots. Therefore, comparing the two cases, the power saving effect of the micro sleep mode can be seen that the longer the frame length is advantageous.

On the other hand, the proposed MAC protocol removes the constraint that the frame length should be short due to the nature of totally contention-free.

Therefore, it can be concluded that it is advantageous to make the transmission frame period as long as possible if only the upper bound is observed that the transmission frame period of the MAC protocol according to the present invention should be smaller than the smallest CTD among the CTDmax of each service.

5. Scheduling

Scheduling algorithms are very important in forming an unified bandwidth-on-demand platform for wireless ATM services. In particular, it is one of the key elements in the WATM MAC protocol that pursues statistical multiplexing for variable bit rate traffic.

1) Uplink Scheduling of AP

Terminals having VCs of CBR traffic satisfy CTD and CVD by maintaining a sync field by using a DTDM scheme when setting up a new call or releasing an existing call.

In the reserved field, VCs of rt-VBR traffic are allocated to the corresponding terminals as many slots as necessary in the next frame based on the DP map in the reserved burst header portion transmitted by each terminal in the uplink. That is, since the slots are allocated based on the required time and the remaining time in the DP transmitted by each VC to ensure the CTD and CVD for real-time traffic.

If the total number of slots required in the next frame by the VCs of rt-VBR traffic is less than the available slot number, a round-robin scheme is used for terminals having VCs of nrt-VBR, ABR, or UBR traffic. Slots are assigned in a weighted round-robin fashion with reference to static parameters. In the case of a weighted round-robin method, weight may be determined based on other priorities of traffic (eg, nrt-VBR-> ABR-> UBR) or information on data generation rate.

When the number of slots that can be allocated in the next frame for each terminal is determined as described above, each terminal is notified of the reserved burst having the length of the slot number through the next frame header.

2) Uplink Scheduling of WT

The uplink scheduler of the WT manages each VC. Since the VC with CBR traffic is assigned its own synchronization burst at the time of call setup, the uplink scheduler of the WT has little role. Whenever there is synchronization information in the frame header, the position of the synchronization burst should be changed.

A VC with rt-VBR traffic must manage the residual time (in slots) of the wireless ATM cell coming into the transmission buffer. Based on this, the uplink scheduler of the WT must determine how many slots should be allocated in the next frame. Figure 6 illustrates the operation principle of the uplink scheduler of the WT for the VC of the rt-VBR traffic. Referring to FIG. 6 (a), when the wireless ATM cells are transmitted through the current frame, the DP is determined based on the residual time (in slots) of the cells in the transmission buffer. If the frame period is assumed to be 20 slots, the residual time of the first cell in the transmission buffer is 29 (in slots), so it must be processed after the current frame (20 in slots). In addition, since the cells to be processed in the next frame are 4 (residual time: 29, 30, 35 and 39 in slots), DP (1, 4) is transmitted to the piggy-back. When four slots are allocated through the next frame header, these four cells are transmitted through the corresponding frame. At this time, the residual time of the first cell in the transmission buffer is 47 (in slots). do. In addition, since there are three cells to be processed in the next second frame (residual time: 47, 50, 52), DP (2,3) is transmitted to the piggy-back.

If the requested slot is reserved, the dynamic parameter expressed as a pair of the requested slot m, the number of frames n is DP [m, n], the frame length L _F , and a reference to the delay limit. The residual life time of the queued cell at the i th position of the Τ _R ⁽ⁱ⁾ In this case, n and m in DP [m, n] are represented by equations (1) and (2).

As shown in FIG. 6 (a), FIG. 6 (b) transmits DP (1,4) to allocate four slots in the next frame to transmit four cells. At this time, if the cells do not arrive in the transmission buffer and are empty, the required slot count is zero. In this case, since the vaporization to be allocated to the uplink slot is lost, the piggy-back method of DP cannot be maintained. Therefore, in this case, the predicted residual time (in frame) is determined based on the dynamic parameter (SP) of the corresponding VC, and the required slot number is sent as 1. Where R is the predicted residual time in the frame based on the static parameter SP of the VC.

6 (c) shows a case in which, as in FIG. 6 (a), DP (1,4) is transmitted, three slots are allocated instead of four slots in the next frame. At this time, the WT discards the fourth cell or performs other implicit UPC (Usage Parameter Control) control.

FIG. 6 (a) corresponds to a case where the arrival interval between cells of the corresponding VC is smaller than the corresponding CTD. In this case, the wireless ATM cells are always waiting in the transmission buffer.

Fig. 7 (a) illustrates this. If the data rate is 23kbps-1Mbps and CTD = 30msec, at least two cells are always waiting in the buffer, as shown in FIG. Up to 60 cells are waiting in the buffer.

7 (b) corresponds to a case where the arrival interval between cells of the corresponding VC is equal to or larger than the corresponding CTD. In this case, the transmission buffer is always empty when the cell is transmitted. Figure 7 (b) is a schematic of this. If the data rate is 16Kbps and CTD = 30msec, one cell is generated per 60msec. Therefore, the transmission buffer is always empty when the cell is transmitted.

When the rt-VBR traffic is largely included in FIG. 7 (a) and the difference between the maximum and minimum values of the data rate is very large and includes both FIGS. 7 (a) and (b), and belongs to FIG. 7 (b). Can be classified as a case. However, based on foreseeable services in wireless ATM systems, the first case is expected to be common and the third is rarely expected.

3) DP transmission method

The DP transmission scheme that can timely sort the time-varying slot requirements can be classified into a competition scheme and a piggy-backing in-band scheme. A factor that may cause DP transmission delay is that when a packet is transmitted in a competitive manner through a slot designated in the uplink, piggybacking is performed by different delay time and in-band signaling during contention. The slot allocation can be largely classified as a case of losing the opportunity of DP transmission.

In the MAC protocol according to the present invention, in order to timely reflect the rt-VBR traffic characteristics, which are changed instantaneously, the DP protocol is avoided by a competition method and transmitted in piggy-back in principle.

The problem that occurs when the DP is piggy-backed is that the uplink slot is not allocated to a specific UE and thus the loss of the opportunity for DP transmission and the burst of the piggy-backing DP are lost in the wireless section. It can be seen as a case.

In the former case, since the uplink slot allocation for a specific UE is guaranteed by introducing a residual time, the problem due to the loss of opportunity of DP transmission can be overcome. In the latter case, this problem can be overcome by slot assignment based on the previously received DP. That is, if the details of previously received DPs were (2,3), the AP uses (2,3) as the lost DP value. This may be best if the traffic is not instantaneous. However, if the instantaneous change is a large amount of traffic, more slots or fewer slots are allocated than the actual number of slots required. If more slots are allocated than the required number of slots, this is not a problem. However, if less slots are allocated, QoS of the VC should be guaranteed through cell discarding or implicit UPC control.

QoS characteristics Traffic classification Delay limit DP [n, m] Slot Reservation Policy m n Transmission mode preference Dynamic polling Delayed sensitivity CBR max_CTD / CVD N / A SYNC One Deterministic rt-VBR max_CTD / CDV Equation 2 Equation 1 RES 2 Delay nrt-VBR mean_CTD 3 Probabi-listic SD ABR N / A Nq 4 WRR UBR N / A Nq 5 WRR

In Table 2, Formula 2 is Equation 1 is to be. And L _F is the length of the frame, Is the actual or predicted residual life time of the cell queued at the i th position of the buffer with reference to the delay limit. N _q Is the number of cells waiting in the buffer, SD is Semi-Deterministic, and WRR (Weighted Round Robin) is weighted round robin.

Table 2 summarizes the types of DPs and slot reservation policies applied to different ATM traffic classes. Slot allocation for all types of ATM service classes is based on a dynamic polling scheme. The dynamic polling scheme provides the basis for the contention free MAC protocol. The CBR traffic class is served in true synchronous transmission mode by fixed slot assignment. In contrast, the rt-VBR class is served by determinisitic slot scheduling under a given max_CTD. Since CTD is intended to guarantee nrt-VBR in an average sense, it is scheduled in a semi-deterministic manner as the residual lifetime for traffic demands changes. Finally, ABR and UBR traffic classes are serviced under a weighted round robin policy at the lowest priority. That is, the remaining slots are allocated after the CBR, VBR, and VBR traffic classes are serviced. Due to the dynamic nature of the traffic requirements for the VBR, ABR, and UBR service classes, dynamic parameters are required, each of which is dependent on the traffic characteristics and QoS requirements. Rely on to transmit other forms of information. In particular, dynamic parameters are optimized to support deterministic scheduling for delay-sensitive traffic.

On the other hand, Figure 8 shows a functional block of the AP (Access Point) for processing and generating the transport frame, including a medium access control means, large cell conversion converting an ATM cell to a WATM cell, WATM cell to an ATM cell A transport frame generation unit for generating a sub-, scheduler, frame header and constituting a downlink burst, and a transport frame breaker for extracting DP and WATM cells from the burst of the transport frame from the WT. The scheduler receives the contents from the transmission queue, receives the DP extracted from the frame breaker, and generates burst map information.

FIG. 9 illustrates a functional block of a wireless terminal (WT) for processing and generating the transport frame, including a medium access control means, wherein a cell conversion unit for converting an ATM cell into a WATM cell and a WATM cell into an ATM cell; A burst generator for receiving DPs and burst positions from the scheduler, generating uplink bursts, and a transport frame decoder for extracting frame headers and WATM cells using burst positions received from the scheduler in the transmission frames received from the AP. Is done. The scheduler receives the contents from the transmission queue, receives the frame header extracted from the transport frame decoder, and generates burst positions, DPs.

According to the present invention, there is provided a transport frame structure and MAC protocol that can guarantee QoS according to various traffic characteristics. In the MAC protocol according to the present invention, a fixed length transmission frame may be divided into an uplink and downlink field, and its boundary may be changed. In addition, the transmission frame according to the present invention minimizes the frame overhead through an efficient burst structure and sufficiently guarantees the scheduling processing time of the AP.

The sync field guarantees CTD and CVD of CBR traffic. The reserved field serves rt-VBR, nrt-VBR, ABR, and UBR traffic. rt-VBR traffic is scheduled based on DP and SP (Static Parameter) and the remaining traffic is based on SP during call setup to ensure priority according to traffic characteristics and to introduce residual time (in frame) in DP. Ensure CTD and CVD of traffic. In addition, the MAC protocol according to the present invention operates in a totally contention-free manner by using a residual time (in frame) in the DP so that the DP can be transmitted by only a piggy-back method. However, a contention field is required only for transmitting a call setup / release signaling message in uplink.

In addition, in the MAC protocol according to the present invention, if the number of slots actually allocated is smaller than the number of slots required by the DP having the rt-VBR traffic characteristic, the corresponding WT performs implicit UPC, so that the characteristic service QoS of the corresponding VC even under heavy load. Can be reflected as much as possible.

Claims (17)

Base station (AP); At least one wireless terminal; And Medium access control means for controlling ATM data transmission between the base station and at least one wireless terminal through a wireless link using a predetermined wireless ATM MAC protocol, The transmission frame used in the wireless ATM MAC protocol is And a frame structure consisting of a frame header, an uplink field for uplink transmission from the base station to the radio terminal, and a downlink field for downlink transmission from the radio terminal to the base station. The wireless ATM communication system of claim 1, wherein a boundary between the uplink field and the downlink field is variable. The method of claim 2, wherein the uplink field is A contention field for transmitting call establishment and release signaling messages; A sync field to which a slot of a fixed time band is allocated; And It consists of a reserved field assigned slot by request. The downlink field is A sync field to which a slot of a fixed time band is allocated; And Wireless ATM system, characterized in that the reservation field is assigned to the slot by request. The method of claim 3, wherein the uplink field is The sync field is located in front of the reserved field, The downlink field is Wireless ATM system, characterized in that the reservation field is located in front of the synchronization field. The method of claim 4, wherein the sync field is For CBR traffic, The reservation field is Wireless ATM system characterized for rt-VBR, nrt-VBR, ABR and UBR traffic. The method of claim 3, wherein the sync field and the reservation field is And a burst, which is a slot or a collection of slots assigned to the wireless terminal. The method of claim 6, wherein the frame header is And a burst map indicating network ID, base station ID, link synchronization information, number of terminals serviced in the reserved field, and a slot allocation result. The method of claim 7, wherein the link synchronization information is When the call is released or added, it consists of uplink synchronization information and downlink synchronization information for synchronizing uplink and downlink synchronization, The uplink synchronization information and the downlink synchronization information And a reference offset indicative of a reference position on the frame and a shift value indicative of the number of slots in the burst in which the call is released or added. The method of claim 7, wherein the burst map Consisting of a terminal ID, an uplink map, and a downlink map, The uplink map and the downlink map are A wireless ATM system comprising an offset indicative of a position in a frame and the number of slots assigned to the wireless terminal. 7. The method of claim 6, wherein the burst At least include a preamble, a burst header, The burst header of the reserved field is a dynamic parameter representing a dynamic parameter set of virtual channels (VCs) having the characteristics of rt-VBR traffic in the wireless terminal, network ID, base station ID, wireless terminal ID, the number of slots allocated in the current frame. A wireless ATM system comprising a map (DP Map) and a response map (ACK Map) for responding to receiving data transmitted in the downlink. The method of claim 10, wherein the DP map For VBR, includes traffic class information, time remaining in the frame, and the number of slots requested. For ABR and UBR, a wireless ATM system comprising traffic class information and the number of cells in the buffer. The method of claim 10, wherein the ACK map A wireless ATM system comprising a Mobile Virtual Channel Identifier (MVCI) and ACK Information. 6. The method of claim 5, wherein the slot or burst allocation in the reserved field is Wireless ATM system which guarantees QoS of rt-VBR by assigning to rt-VBR first. The method of claim 13, Slot or burst assignments in reserved fields A wireless ATM system characterized by weighted round robin for nrt-VBR, ABR and UBR traffic. The method of claim 10, DP transmission is done by piggy-backing If the uplink slot is not allocated to a specific terminal and thus the DP transmission opportunity is lost, slot allocation is performed using a predicted residual time to deliver the rt-VBR within a predetermined request time. A wireless ATM system characterized by slot assignment based on previously received DPs when a burst piggy-backing is lost in the radio section. The method of claim 10, In the instantaneous traffic, when the wireless terminal is allocated fewer slots than the required number of slots, cell discarding or implicit UPC control is used to guarantee QoS of the corresponding virtual channel (VC). The method of claim 1, wherein slot allocation scheduling of uplink A wireless ATM system, characterized in that distributed scheduling is performed in the base station and the wireless terminal, respectively.