Abstract: Apparatus, and associated method, converts real-time multimedia information generated pursuant to an RTP protocol into a form amenable for transmission upon a radio channel, such as a radio channel defined in a cellular communication system. When converted, the informational content of the multimedia information is transmitted in a manner that achieves spectral efficiency and low, constant delay. Once transmitted over the radio channel, the multimedia information is converted back into form corresponding to the RTP protocol before being sent to the receiving station.

Abstract: A multiple mode data communication system and method provides the flexibility to schedule wireless unit transmissions and/or allow the wireless unit to transmit autonomously. In certain embodiments, the wireless units can transmit autonomously and/or use scheduling depending on the data rate, the length of the data packet or the type of data. For example, the wireless units can transmit autonomously at lower data rates and use scheduling at higher data rates. Thus, the multiple mode system enables wireless unit transmissions to be scheduled and/or be transmit autonomously, and wireless units can simultaneously operate in different scheduling and/or autonomous modes.

Abstract: A cable modem communicates the timing of the arrival of certain packets (such as TCP ACK packets) to a cable modem termination system. This timing feature is useful in methods for increasing the throughput in the downstream direction by eliminating TCP ACKs backing up at a cable modem. In particular, a cable modem termination system implementing an unsolicited bandwidth grant service in which unsolicited grants of bandwidth are sent by the cable modem termination system to the cable modem. The grants of bandwidth are timed to arrive at the cable modem simultaneous with or shortly after the arrival of the TCP ACK from an end station connected to the cable modem. Several methods of calculating or predicting when the unsolicited grants should be sent to the cable modem are described. The method is also applicable to other types of packets, such as voice packets from a end station implementing a Voice over Internet Protocol (VoIP) application.

Abstract: A port on a network device engages in auto-negotiation on a network link during a first operational state to select a transmission mode, either half duplex or full duplex. If half duplex operation is selected, the port commences half duplex operation in a second operational state. During the second operational state, the link is monitored for an error condition indicating that another network device attached to the link may not be operating in a half duplex mode. This error condition includes the occurrence of excessive collisions or late collisions. When the error condition is detected, the port commences full duplex operation in a third operational state, based on the presumption that device at the other end of the link may be configured for fixed full duplex operation. If proper operation ensues, the port remains configured for full duplex transmission.

Abstract: A Resource Reservation System includes a Token Generation Unit (TGU) which generates and circulates among nodes of a communications system a Slotted Token (SLT) message having sub-fields to carry identification number for each input port in a node and the resource available for each input port. On receiving the message the Resource Control Unit (RCU) in each node can write port identification number, available resource in appropriate sub-fields of the SLT message, and reserve resources in other nodes by adjusting information in the sub-field associated with the other nodes.

Abstract: An ATM network, in which the downward data rate, from the network to the users, is greater than the upward data rate, from the users to the network. Multiplexers are provided for establishing connections, constituting virtual channels, between users and the network; the virtual channels are grouped into virtual paths. In each multiplexer close to the user, the bandwidth allocated to each downward virtual path is variable under the control of a call control means provided upstream in a switching node, and the upward virtual channels have a fixed bandwidth. Preferably, in the downward direction, each virtual channel is assigned a permanent or semi permanent quality of service.

Abstract: A method for sharing internal excess bandwidth between output and input termination modules of a switching network including a switch core fabric (FC) via which a plurality of input termination modules (ITM1 to ITMn) communicate with a plurality of output termination modules (OTM1 to OTMm) through at least a point-to-point transmission channels considered as corresponding each to a virtual ingress-to-egress pipe (VIEP). Sharing of internal excess bandwidth is obtained by successive steps including a minimum bandwidth request calculation step, each request being transmitted to an output termination module for obtaining a minimum bandwidth grant in return. The minimum bandwidth request and grant related to an input termination module linked by an ingress-to-egress pipe to an output termination module are both calculated for a determined number K of relative administrative weights corresponding each to a different quality of service, with a different request and a corresponding grant for every weight.

Abstract: A method is provided for transmitting data packets from a source device in a wireless network. The source device receives a channel time allocation identifying the source device as assigned to transmit and a destination device as assigned to listen during the channel time allocation. If the source device has any primary data to send to the destination device, it will do so during the channel time allocation. If time remains in the channel time allocation once the primary data (if any) has been sent to the destination device, the source device will determine whether it has any secondary data to send to a secondary device. If so, the source device will determine whether the secondary device will be listening during the channel time allocation. If the secondary device will be listening, the source device then sends the secondary data to the secondary device during the channel time allocation.

Abstract: For transmitting delay-critical data in a digital, time division form in an additional channel of a cable television system, the slots of the channel are further divided into smaller mini slots, for the indication of which the same cyclic indication is used as with which the superframes controlling the use of the channel indicate the original slots. A method based on mini slots is compatible with DAVIC 1.0 and 1.1 specifications.

Abstract: In a system, method, and apparatus according to an embodiment of the invention, traffic on a basic access channel and a reserved access channel is managed to maximize use of the basic access channel while minimizing delays.

Abstract: A method for control of packet data transmissions in a TDMA wireless network to provide for additional choices in the allocation of communication channels. The fixed relationship in the timing of the downlink allocation signalling and subsequent uplink transmission is altered for certain classes of mobile station to avoid physical constraints. Examples of variations in USF signalling in GPRS are given.

Abstract: It is the object of this invention to provide a method of increasing the data throughput of a multi-hop wireless link. A method is provided which mitigates self-interference, without precluding the use of omni-directional transceivers. Distributed protocols for channel allocations in a multi-hop wireless communication system are described. These protocols result in channel allocations that increase the capacity utilization of the network and render the system robust to localized interferers and jammers.

Abstract: A method and system for transferring a plurality of messages in an Ethernet industrial control environment. The messages are tagged with identifiers of varying levels of priority. The system has a serial network bus. Clock synchronization messages generated by a master device are tagged with a higher priority identifier, while other message types are tagged with a lesser priority identifier. Data having the highest priority identifier is placed onto the bus before placing data with a lesser priority identifier onto the bus.

Abstract: All upstream messages that are desired to be sent from one of a plurality of settop terminals sharing a common upstream channel are segmented into data packets through an adaptation layer before sending into the upstream channel by a settop terminal, using the present invention using a hybrid of contention and reservation methodologies. If the upstream message is lengthy, a user settop terminal can request and gain exclusive control over the upstream channel and transmit the message using a reservation and self-acknowledging mechanism. In accordance with the present invention, a combination reservation mechanism and calculation method to optimize random backoff time for upstream transmission is added to conventional contention based Media Access Control methods and this embodiment to substantially enhance performance.

Abstract: A method for control of packet data transmissions in a TDMA wireless network to provide for additional choices in the allocation of communication channels. Measurement and recovery periods are re-assigned to avoid conflicts in operating conditions. The re-assignments for the GPRS system may be reduced to a simple formula.

Abstract: A network device monitors a signal transmitted to a wireless or optical link and a signal received from the link for detecting a bit-by-bit coincidence between them. In response to the detection of the coincidence, the network device determines that the received signal is a copy of the transmitted signal. The network device further monitors its transition states for detecting a predetermined state which would persist indefinitely during a link failure. When the predetermined state and the copy of the transmitted signal are simultaneously detected, the network device discontinues its predetermined state and enters a normal state.

Abstract: A method of providing network access across a shared communications medium between competing users includes the steps of monitoring network access usage by each user for a past time interval and, based on the monitored network access usage, allocating network access for each user during a future time interval. Features include forecasting network access that will be utilized or requested by users in a future time interval, and prioritizing the users for allocating network access to the users.

Abstract: To allow many users to efficiently use the functions of a processing server that performs predetermined processing, via a network and also to prevent interference by illegal users. In a content supply system 100, in order to use a streaming server 102 to perform a live distribution, a user PC 106 to be used makes a reservation for a time zone, etc. to a server reservation control center 101. When the reservation is accepted, the user PC 106 sends a reconfirmation (reconfirmation of the reservation) to the server reservation control center 101 by six hours before the distribution start time according to the reservation. If the reconfirmation is not made by six hours before, the server reservation control center 101 cancels the reservation. On the other hand, if the reconfirmation is made by six hours before, the server reservation control center 101 confirms the reservation and carries out billing processing.

Abstract: A method and apparatus for reserving bandwidth in a network includes a series of elements. A demand matrix is calculated, for bandwidth requirements based upon communication needs among a plurality of nodes on the network. An integer number of time slots is provided, aligned around the network. Bandwidth is reserved for node-to-node communication based upon the demand matrix. The reserving of bandwidth reserves bandwidth between two nodes based upon time-slot alignment. Transmission is scheduled between the two nodes by reservation of wavelengths and time slots.

Abstract: A method and an apparatus for user-based provisioning of distribution channels in a communications network allows an end user to select and initiate digital distribution channel allocation to accommodate their needs instead of submitting a service order to the telephone company each time a change in channel allocation is desired. In one implementation, a user-accessed provisioning terminal at a Distant Terminal (DT) receives a subscriber's distribution channel allocation selection after the user is authorized. The user's allocation selection is transmitted to a Remote terminal (RT) via a control channel, such as the Facility Data Line of an ESF-type T1 line or a dedicated data link that directly connects the DT and an RT. When the RT receives a provisioning message from a DT, the RT confirms that the provisioning selection is acceptable and automatically rearranges its time-slot interchange (TSI) connections according to the provisioning change initiated by the user.

Abstract: To address the need for a communication infrastructure and method to speed uplink data setup, the present invention provides for the assignment of uplink packet data resources by basestation transceiver systems (BTSs) without the need to communicate with any packet control unit (PCUs) first. The present invention accomplishes this by reserving packet data resources before they are needed or requested and providing them to BTSs for assignment. Thus, BTS-PCU communication occurs in the period before an uplink connection is needed and after uplink data is established, effectively eliminating the BTS-PCU delay from uplink data setup. Moreover, the present invention provides for the transmission of transmit allowance messages before an uplink request is made by the communication unit, further reducing uplink data setup time.

Abstract: A multiple access communication protocol that includes an uplink and a downlink channel is disclosed. The uplink channel has a plurality of frames, such that each frame has a first selectable number of minislots and a second selectable number of slots. A reservation request of a first type is sent into a first selected minislot of a selected frame of the uplink channel when information of a first type is to be sent. The reservation request of the first type requests an assignment for at least one slot for transmitting information of the first type in at least one frame that is subsequent to the selected frame. A reservation request of a second type is sent into a second selected minislot of the selected frame when the second selected minislot is available in the selected frame and when information of a second type is to be sent.

Abstract: A method and system for transferring one or more sequentially ordered data files to a plurality of secondary systems that respond after receipt of each file. A clear-to-send (CTS) flag is maintained for each of the secondary systems. A sequence broker reads a clear-to-send flag and, if the CTS flag is asserted, issues a transfer command to a transmit module to transmit a next data file to the secondary system. The sequence broker reads a status file associated with a secondary system and determines which data file, if any, is to be transferred. The sequence broker receives invoking commands from a clear-to-send broker and/or an invoking module for invoking the transfer process.

Abstract: A method and apparatus for requesting and allocating bandwidth in a broadband wireless communication system. The inventive method and apparatus includes a combination of techniques that allow a plurality of CPEs to communicate their bandwidth request messages to respective base stations. One technique includes a “polling” method whereby a base station polls CPEs individually or in groups and allocates bandwidth specifically for the purpose of allowing the CPEs to respond with bandwidth requests. The polling of the CPEs by the base station may be in response to a CPE setting a “poll-me bit” or, alternatively, it may be periodic. Another technique comprises “piggybacking” bandwidth requests on bandwidth already allocated to a CPE. In accordance with this technique, currently active CPEs request bandwidth using previously unused portions of uplink bandwidth that is already allocated to the CPE.

Abstract: A wireless communication network includes a plurality of mobile nodes each including a transceiver, a phased array antenna connected to the transceiver, and a controller connected to the transceiver. The controller schedules time slots for each time frame to establish a communication link with each neighboring mobile node. An initiating mobile node transmits a request for time slots to the receiving mobile node, which transmits a reply to the initiating mobile node. The initiating mobile node transmits a confirmation to the receiving mobile node, and the receiving mobile node transmits the reply again if the confirmation is not received. Alternatively, the receiving mobile node may transmit an acknowledgment to the initiating mobile node, and the initiating mobile node transmits the confirmation again if the acknowledgment is not received.

Abstract: The present invention concerns a method for terminals to have access to a common resource of a network. It is characterised in that the said network defines the access conditions of a plurality of access classes and transmits the said conditions to all the terminals liable to have access to the said resource and in that a terminal wishing to have access to the said resource determines the access class to which it belongs according to its access state and gains access to the said resource according to the access conditions of the said access class thus determined.

Abstract: When packet sending and receiving apparatus 21 sets a connection, timing control apparatus 22 generates a timing information Tf as the packet is dispersed equivalently. Timing control apparatus 22 notices the timing information Tf to packet sending and receiving apparatus 21 and base station 3. Packet sending and receiving apparatus 21 carries out a packet generating processing in accordance with a frame offset value which is indicated by the timing information Tf. Therefore, the packets in which a packet transmission timing is averaged in a packet transmission period arrives to packet multiplex apparatus 23. Consequently, it is possible to decrease a waiting time of the packet multiplex transmission. Therefore, it is possible to use efficiency a transmission link L1, while being satisfied the required service quality.

Abstract: A method is provided for transmitting data packets over a bi-directional contention and reservation based network. The network includes an operably linked system controller for receiving upstream channel packets and originating downstream channel packets. At least one operably linked remote terminal is included for receiving the downstream channel packets and originating the upstream channel packets. The system controller provides periodically allocated grants to the at least one remote terminal in the downstream channel for scheduling data packet transfers in the upstream channel. The periodically allocated grants have a fixed bandwidth size. The system controller also provides dynamically allocated grants to the at least one remote terminal in the downstream channel upon request of the at least one remote terminal for scheduling data packet transfers in the upstream channel. The dynamically allocated grants are of a requested bandwidth size.

Abstract: A method and an apparatus for transmitting data in a linear-type or ring-type network structured by a plurality of nodes and both-way transmission lines each connecting between adjacent nodes includes that each node operates as a left TE, a right TE, or an IE. The left and right TEs prepare token packets each including a transmission right and packet trailers each including data packet storage area. The left TE transmits the packet trailers on a right direction line of the both-way transmission line.

Abstract: An approach for allocating system capacity of a communication switching system for exchange of traffic is disclosed. The system includes multiple terminals that request allocations of system capacity. The capacity is partitioned into a provisioned portion and an unprovisioned portion, in which a portion of the terminals constitutes a pool having a plurality of sub-pools. According to one embodiment, a control computer communicates with the plurality of terminals and allocates the provisioned portion of the capacity to the plurality of sub-pools of the terminals. The provisioned portion of the capacity is arranged into sub-partitions, wherein one of the sub-partitions is not associated with the sub-pools of terminals. Remaining sub-partitions are associated with the sub-pools of terminals.

Abstract: Disclosed are systems, methods, computer program products and computer data signals for broadcasting a beacon packet to one or more client stations and for processing a beacon packet. The beacon packet includes a preamble, a header and a data portion. In one broadcasting method, it is determined if there is any data buffered for any of the client stations. If there is data buffered, a traffic indicator flag located before the data portion of the beacon packet is set to a first logic value. If there is not any data buffered, the traffic indicator flag is set to a second logic value. The beacon packet is broadcast to the client stations.

Abstract: A communication unit (110) that wants to transmit a data packet to another communication unit (105) must acquire access to a common communication channel (not shown) before transmitting a data packet (440). For data packets of realtime applications, quality of service (QOS) parameters for the data packet are used to define transmission parameters to communicate the data packet (440). These parameters include Taccess (420) and Tdelay (430). In addition, compliance with predetermined requirements of size relationship between request-to-send (RTS) and clear-to-send (CTS) packets are imposed.

Abstract: Requests are processed to transmit data packets upstream from a cable modem to a cable headend in a manner that minimizes the use of CPU operations and/or memory capacity. Data packets to be transmitted upstream are stored at the cable modem. The data packets each have a given transmission data byte length value. Burst profiles are received successively at the cable modem. Each time a new bust profile is received, a set of physical data length values corresponding to respective transmission data byte length values is calculated from the parameters of the received burst profile. The calculated set of physical data length values is stored in memory so the individual values can be retrieved from the transmission data byte length values again and again, rather than being re-calculated each time a conversion is made from transmission data byte length values to physical data length values. The same set of physical data length values is used until a new burst profile is received by the cable modem.

Abstract: A wireless communication network includes a plurality of mobile nodes each including a transceiver, a phased array antenna connected to the transceiver, and a controller connected to the transceiver. The controller schedules a respective semi-permanent time slot for each time frame to establish a communication link with each neighboring mobile node and leaves at least one available time slot in each time frame. Each time frame has up to N semi-permanent time slots and at least 2N?1 available time slots. The controller also schedules the at least one available time slot to also serve the communication link with a neighboring mobile node based upon link communications demand. The phased array antenna is aimed by the controller towards each neighboring mobile node during communication therewith.

Abstract: A dual mode mobile unit is arranged to communicate in either a first or second data communications standard, such as combined Bluetooth and 802.11 operation. An interface unit converts received Bluetooth or 802.11 format signals into 802.11 frame format data signals to be provided to a digital signal processor which is programmed to process signals in either standard. The dual mode mobile unit can operate in the 802.11 standard to reserve a time interval for Bluetooth activity during which other 802.11 units will avoid-transmissions to avoid interference.

Abstract: A communication system for communicating on a network that includes communication devices performs communications in a connected mode or a non-connected mode. For at least one of the communication devices, to effect a transmission in the connected mode, the system performs an information operation during which an item of information representing a passband necessary for the transmission in the connected mode is broadcast on the network. The system performs a passband allocation operation to allocate the passband for connected-mode transmissions, based on the item of information. A second allocation operation is performed to allocate, for non-connected-mode transmissions, all or part of the passband not allocated for the connected-mode transmissions. The system adjusts the allocated passband to avoid congestion on the network.

Abstract: For achieving elimination of unfairness between ports, reserved output port information transferred between respective modules is input to switch out of the module to vary destination of output. The module and the switch operate in synchronism with the frame for which the connection grant process of a plurality of time slot is performed to vary connection topology so that all connection topology appear. By variation of connection topology, variation combination of adjacent port appear to shuffle preference for the input port which is otherwise held fixed for resolving unfairness relating to reservation chance of the input port.

Abstract: Methods for reserving call units of bandwidth and for using the reserved call units to manage call requests are disclosed. Reservations are requested by a first host device (e.g., zone controller) for a path of a packet network communication system. The reservations are granted or denied by the network based on the availability of the requested bandwidth. Once a reservation has been obtained, the number of call units of bandwidth associated with the reservation may be reduced or increased by the network based, for example, on link failures, repairs, etc. Call requests are granted or denied by the zone controller based on the path(s) needed for the call, the number of reserved call units associated with the path(s) and the amount of call units required to support the call. If there are sufficient reserved call units to support the call, the call may proceed by sending, from a second host device (e.g., repeater), a message that is distributed over the number of units of bandwidth needed for the call.

Abstract: A communication system comprising three communication resources: a contention-type access block, a non-contention access block and a second non-contention access block called a reserved block. Each time that a remote unit has a block of data to transfer to a hub station, it sends the block of data over the contention-type access block. It also sends a corresponding notification message over the reserved block. If the hub station receives the notification message but not the block of data, it sends a response message to the remote unit which designates a resource within the non-contention access block. The remote unit then sends the block of data to the hub station over the designated resource.

Abstract: A method of determining the position of the split between uplink and downlink bandwidth, in a point of multipoint radio access system with time division duplex scheme comprising a certain number of user terminals and a base station has been disclosed, wherein there are at least two quality of service classes, a first class for guaranteed services (RT) and a second class for not-guaranteed/best effort services (BE). The MAC layer evaluates and controls a further movement of the split—as that initially determined by a Call Admission Control (CAC)—according to the behaviour of uplink and downlink not-guaranteed/best effort queues observed during a certain observation period.

Abstract: A technique to identify a response cell in a ranging grant procedure is disclosed herein. The format of the response cell reduces the probability of erroneous response cell detection. The response cell is a conventional ATM cell whose payload includes multiple cell delineation bytes (CDBs).

Abstract: Disclosed is a channel allocation method on performing a data communication in a wide band wireless multi-media communication system, which allocates selectively reserved time slots or contention time slots, according to the quantity of data to be sent. In the method, contention time slots are used for sending data if the quantity of data to be sent is smaller than a critical value, or reserved time slots are used if the data quantity is greater than the critical value.

Abstract: A subscriber-line-terminating apparatus for dynamically allocating band portions to a plurality of terminal apparatuses includes an in-buffer-information-amount receiving unit for receiving an in-buffer-information amount from each of the terminal apparatuses; an insufficient-band-computing unit for computing an insufficient band portion required by each of the terminal apparatuses; an in-buffer-information-amount-proportional-band-allocating unit for allocating a band portion corresponding to the in-buffer-information amount to each of the terminal apparatuses and a past-use-band-allocating unit for allocating a past-use band part to each of the terminal apparatuses as a past-use band portion based on a first past-use band variable of the terminal apparatus.

Abstract: Scheduling techniques for communication applications using receiver directed broadcast schemes are disclosed. The invention includes techniques for the implicit reservation of receive slots and techniques for the optimization of receiver directed broadcast schedules. The implicit reservation scheme includes the mechanics of implicit reservation. Implicitly reserved slots can be reclaimed by their owners. Further, simultaneous implicit reservations can be identified and resolved. Procedures are also provided for determining the number of channels and slots required to optimize a receiver directed broadcast schedule for a neighborhood of a given number of nodes.

Abstract: In a power splitting passive optical network, TDM/TDMA communication is employed for downstream/upstream transmission over a fiber. A framed structure is used for the downstream transmission from an optical line card (OLC) at the network end to a plurality of optical network units (ONUs), which are each connected to end user equipment. A framed structure is also employed for upstream burst transmission from the plural ONUs to the OLC. In the upstream direction each ONU transmits at most one burst per frame that includes a header and a payload containing a variable number of bytes that is adjustable on a continuum. The length of each payload in a burst transmitted upstream by an ONU is determined as a function of the bandwidth requirements of the end user equipment connected to that ONU as well as the bandwidth requirements of the end user equipment at the other ONUs.

Abstract: An adaptive slot allocation system (50) is connectable to a data transmission system that transmits data from a transmitter (10) to a plurality of receivers over a common channel in successive time slots, each time slot being allocatable to one particular receiver for transmitting data thereto, there being for each receiver during each time slot, a given acceptable transmission rate (ATR), derived from a corresponding measured signal-to-noise ratio (SNR) reported by the receiver. All subscriber units the transmission queue currently holds data to it will be referred as belonging to a queue group. The adaptive slot allocation system (50) includes a queue group identifier (53), operative to identify all receivers belonging to the queue group and a rate factors calculator (54), operative to determine for each receiver of the queue group a rate factor.

Abstract: Generalized Processor Sharing (GPS) is a scheduling discipline which provides minimum service guarantees as well as fair resource sharing. The performance of GPS is governed by the scheduling weights associated with individual connections. The system discloses methods for GPS scheduling that handle an arbitrary number of connection classes and reservation-based weights and admission control techniques to achieve fairness among connection classes. The methods allow statistical multiplexing gains in the presence of multiple traffic and Quality of Service (QoS) classes of connections that share a common trunk. Also disclosed are several novel techniques to compute and adapt the weights.

Abstract: A method and apparatus for early arbitration in a full duplex bus system. Early arbitration in a distributed arbitration serial bus system permits the resolution of requests for a next fairness interval during a current fairness interval such that the grant of the highest priority request in the next fairness interval may immediately follow a last packet of a last subaction in a current fairness interval. In this way, the bandwidth previously wasted propagating an arbitration reset token and waiting for arbitration requests can be substantially eliminated.

Abstract: A multiple access communication protocol includes an uplink channel and a downlink channel is disclosed. The uplink channel has a plurality of frames, such that each frame has a first selectable number of minislots and a second selectable number of slots. A reservation request of a first type is sent into a first selected minislot of a selected frame of the uplink channel when information of a first type is to be sent. The reservation request of the first type requests an assignment for at least one slot for transmitting information of the first type in at least one frame that is subsequent to the selected frame. A reservation request of the second type is sent into a second selected minislot of the selected frame when the second selected minislot is available in the selected frame and when information of a second type is to be sent.

Abstract: The present invention relates to a method for resolving a collision in a communication system using medium access control based on contention. The method of the present invention enables management and control of a contention window size of each mini slot and thus all the terminals may have an equal opportunity to access each mini slot. Moreover, when two or more terminals have simultaneously attempted to access any one mini slot and thus collision has occurred in the mini slot, the method of the present invention restricts the access of the mini slot to the terminal or terminals that had experienced collision, and then permits an access attempt of another terminal after all the terminals which had experienced collision succeed in accessing a mini slot.