摘要:
The system (500), apparatus (400), and method of the present invention provide three architectures for logically organizing multiple channels: a parallel multi-channel superframe (PMS) (100), a sequential multi-channel superframe (SMS) (200), and a non-overlapping multi-channel superframe (NMS) (300). Each of these architectures arises from different trade-offs and is applicable to any multi-channel MAC protocol that is based on the concept of a superframe, e.g., IEEE 802.11 superframe.
摘要:
In order that media access slots MAS are allocated based on minimum latency requirements of, for example, not less than 4 ms, or on a medium utilization efficiency or power consumption requirement for a minimum reservation block length, both high-efficiency and low-latency schemes (or category) need to coexist within a superframe with fair support given to both. The maximization of contiguous available MAS between low-latency and high-efficiency schemes ensures that power saving and overhead risk are minimized without compromising the support for low-latency applications.
摘要:
A plurality of methods, computer program product, and apparatus that use a lower 32 bit field of a 64-bit 802.11 TSF timer, so as to encode the reference time instant without the ambiguity as to whether there the reference time is referring to a future time or a past time. According to an aspect of the present invention, the fact that the low order 32 bits of the TSF timer wraps over in about 71 minutes is exploited to remove any ambiguity in the reference times contained in the Schedule Element frame. One method employs an algorithm base on distance between two reference points to determine whether the timer has wrapped around a time period, and another method uses a delay interval or a timeout to determine whether or not the TSF timer is wrapped or unwrapped. Another method includes determining whether an absolute value of X−O is less than, or greater than or equal to maximum value M/2.
摘要:
A clock synchronization method and apparatus is disclosed for use in a communication system including a plurality of wireless nodes communicatively coupled via a wireless network, each of the plurality of wireless nodes having a local time base, and one of the plurality of wireless nodes being designated as a master node having a master time base which serves as a master clock against which the local time bases are synchronized. The clock synchronization method includes the steps of periodically transmitting synchronization frames to the plurality of non-master nodes so as to adjust the slave clocks associated with the respective non-master nodes. The synchronization frames are distributed from the master node at near-periodic intervals and includes a cycle time value that corresponds to the end of the previously transmitted synchronization frame. The slave clocks (i.e., non-master nodes) receiving the synchronization frame determine the cycle time value at the point of reception of the synchronization frame and adjusts their clocks by calculating a difference value between the received cycle time and a previously saved local cycle time value.
摘要:
The current MBOA UWB MAC protocol requires a device that detects alien devices to include a BP Switch IE in its beacon so that its neighbors may learn the presence of the alien devices and follow that device to relocate their beacons in a coordinated fashion. However, during the transition period of beacon relocation, that device may decide to halt the relocation process as required by the standard and such decisions also have to be received by its neighbors. In such a case, a BP switch IE will be generated by that device which includes a BPST offset equal to a length of a superframe.
摘要:
An apparatus and method is disclosed for announcing to a wireless station in a wireless network that a Quality of Service (QoS) service schedule is pending for the wireless station. The apparatus of the invention comprises a hybrid coordinator that is capable of creating and sending to the wireless station an announcement of a pending Quality of Service (QoS) service schedule. The wireless station delays entering a power save mode of operation until the wireless station receives the QoS service schedule or until a selected timeout period expires.
摘要:
Wireless stations (108-1-108-N) contending for exclusive access for a predetermined period of time (S232) to transmit on a communication medium (112) are regulated by a common external controller (104) using a single timing parameter (S204). Attempts at transmission access are preceded by respective delays that are expired simultaneously and at a common rate by the stations at times when the stations sense the medium to be idle (S224). The delays are pseudo-randomly selected to avoid collisions among stations in their respective access attempts (S208). Default, initial values of the respective delays (S204) applied to the stations, when multiplied by the respective expected number of transmission attempts by the stations over the long term over periods of time when no transmission attempt is unsuccessful, yield respective products equal to a constant value common to all stations (S312). The default values therefore serve as a knob by which the controller regulates air time opportunity.
摘要:
This invention discloses a set of internal signaling (i.e., management primitives) to support a clock-synchronization protocol for wirelessly synchronizing clock registers of wired or wireless nodes via a wireless local area network (i.e., 802.11 network). The clock synchronization is performed between two higher-layer protocol entities residing within two different wireless stations (STAs).
摘要:
Wireless networks and their method of implementation include a first network and one or more networks. The first network assigns designated time slots to each of the one or more networks during which at least one device of at least one of the networks may communicate with at least one other device of its respective network.
摘要:
A local-area network is provided where a plurality of OFDM stations and DSSS/CCK-only stations coexist. A beacon signal having a contention-free-period (CFP) is transmitted from an access point to the plurality of stations. The OFDM-modulated data is transmitted to the plurality of stations before the CFP ends, and after the CFP period ends, the DSSS/CCK-modulated data is transmitted, thereby preventing collisions between the stations.