公开(公告)号：US20030012167A1

公开(公告)日：2003-01-16

申请号：US10187158

申请日：2002-06-28

Applicant: AT&T Corp.

Inventor： Mathilde Benveniste

IPC: H04Q007/24

CPC classification number: H04W74/0816 ,  H04L47/14 ,  H04L47/2425 ,  H04W24/02 ,  H04W40/22 ,  H04W74/006 ,  H04W84/12 ,  H04W84/18

Abstract: A method and system reduce interference between overlapping first and second wireless LAN cells in a medium. Each cell includes a respective plurality of member stations and there is at least one overlapped station occupying both cells. An inter-cell contention-free period value is assigned to a first access point station in the first cell, associated with an accessing order in the medium for member stations in the first and second cells. The access point transmits a beacon packet containing the inter-cell contention-free period value, which is intercepted at the overlapped station. The overlapped station forwards the inter-cell contention-free period value to member stations in the second cell. A second access point in the second cell can then delay transmissions by member stations in the second cell until after the inter-cell contention-free period expires. The beacon packet sent by the first access point station also includes an intra-cell contention-free period value, which causes the member stations in the first cell to delay accessing the medium until polled by the first access point. After the expiration of the intra-cell contention-free period, member stations in the first cell may contend for the medium based on the quality of service (QoS) data they are to transmit, using the Tiered Contention Multiple Access (TCMA) protocol.

Abstract translation: 一种方法和系统减少介质中重叠的第一和第二无线LAN小区之间的干扰。 每个小区包括相应的多个成员站，并且存在占据两个小区的至少一个重叠站。 小区无争用周期值被分配给与第一和第二小区中的成员站的介质中的访问顺序相关联的第一小区中的第一接入点站。 接入点发送包含在重叠站被拦截的小区间无争用周期值的信标分组。 重叠站将小区间无争用周期值转发到第二小区中的成员站。 第二小区中的第二接入点然后可以延迟第二小区中的成员站的传输，直到小区间无竞争时间期满。 由第一接入点站发送的信标分组还包括小区内无争用周期值，其使第一小区中的成员站延迟访问介质，直到由第一接入点轮询。 在小区内无竞争时段期满之后，第一小区中的成员站可以使用分层争用多路访问（TCMA）协议，根据其要发送的业务质量（QoS）数据来竞争媒体。

公开(公告)号：US20030156553A1

公开(公告)日：2003-08-21

申请号：US10256299

申请日：2002-09-27

Applicant: AT&T Corp.

Inventor： Mathilde Benveniste

IPC: H04B007/185

CPC classification number: H04W74/04 ,  H04W56/00 ,  H04W74/06 ,  H04W74/08 ,  H04W84/12

Abstract: A method and system reduce interference between overlapping first and second wireless LAN cells contending for the same medium. Each cell includes a respective plurality of member stations. An inter-cell contention-free period value is assigned to a first access point station in the first cell, associated with an accessing order in the medium for member stations in the first and second cells. The access point in the first cell transmits an initial shield packet to deter other stations from contending for the medium. The access point then transmits a beacon packet containing the inter-cell contention-free period value to member stations in the second cell. A second access point in the second cell can then delay transmissions by member stations in the second cell until after the inter-cell contention-free period expires. The beacon packet sent by the first access point station also includes an intra-cell contention-free period value, which causes the member stations in the first cell to delay accessing the medium until polled by the first access point. After the expiration of the intra-cell contention-free period, member stations in the first cell may contend for the medium based on the quality of service (QoS) data they are to transmit, using the Tiered Contention Multiple Access (TCMA) protocol.

Abstract translation: 一种方法和系统减少了重叠的相同介质的第一和第二无线LAN单元之间的干扰。 每个小区包括相应的多个成员站。 小区无争用周期值被分配给与第一和第二小区中的成员站的介质中的访问顺序相关联的第一小区中的第一接入点站。 第一小区中的接入点发送初始屏蔽分组，以阻止其他站竞争媒体。 接入点然后将包含小区间无争用周期值的信标包发送到第二小区中的成员站。 第二小区中的第二接入点然后可以延迟第二小区中的成员站的传输，直到小区间无竞争时间期满。 由第一接入点站发送的信标分组还包括小区内无争用周期值，其使第一小区中的成员站延迟访问介质，直到由第一接入点轮询。 在小区内无竞争时段期满之后，第一小区中的成员站可以使用分层争用多路访问（TCMA）协议，根据其要发送的业务质量（QoS）数据来竞争媒体。

公开(公告)号：US20030174690A1

公开(公告)日：2003-09-18

申请号：US10256384

申请日：2002-09-27

Applicant: AT&T Corp.

Inventor： Mathilde Benveniste

IPC: H04J003/06

CPC classification number: H04W74/02 ,  H04W56/00 ,  H04W74/0808 ,  H04W84/12

Abstract: Overlapped wireless LAN cells in a medium have an equal chance at establishing a session on the medium. A first member station in the first cell transmits a timing packet containing a timestamp value, which is received at a second member station in the second cell. This synchronizes member stations in the first and second cells to interrupt transmissions at a global channel release instant corresponding to the timestamp value. The member stations in the first and second cells then have the opportunity to contend for access to the medium following the global channel release instant, using a slotted CSMA/CA access method. Each of the member stations in the first and second cells has a superframe clock that is synchronized based on the timestamp value, thereby establishing a periodic global channel release instant during each of a plurality of periodic superframes. The member stations can then periodically interrupt transmissions at the periodic global channel release instant to contend for the medium. The periodic global channel release instant occurs at intervals that are sufficiently close to meet delay and jitter restrictions for time-critical voice and video applications.

Abstract translation: 介质中重叠的无线LAN单元在介质上建立会话时具有相同的机会。 第一小区中的第一成员站发送包含在第二小区中的第二成员站处接收的时间戳值的定时分组。 这使得第一和第二小区中的成员站同步以对应于时间戳值的全局信道释放时刻的中断传输。 第一和第二个小区中的成员站随后可以使用时隙CSMA / CA访问方法在全球信道释放时刻之后争取访问媒体。 第一和第二小区中的每个成员站具有基于时间戳值同步的超帧时钟，从而在多个周期性超帧中的每个期间建立周期性全局信道释放时刻。 成员站然后可以周期性地中断在周期性全球信道释放时刻的传输以争取媒体。 周期性全局信道释放瞬间以足够接近的时间间隔发生，以满足时间关键语音和视频应用的延迟和抖动限制。

公开(公告)号：US20030174665A1

公开(公告)日：2003-09-18

申请号：US10256516

申请日：2002-09-27

Applicant: AT&T Corp.

Inventor： Mathilde Benveniste

IPC: H04B007/185

CPC classification number: H04W74/02 ,  H04W56/00 ,  H04W74/0808 ,  H04W84/12

Abstract: An access method for periodic contention-free sessions (PCFS) reduces interference between overlapping first and second wireless LAN cells contending for the same medium. Each cell includes a respective plurality of member stations and an access point (AP) station. The access method for periodic contention-free sessions (PCFS) includes a fixed cycle time that reduces conflicts with PCFS from other cells. The PCFS from several cells are repeated in cycles of cycle period (CP), which is the contention-free period (CFP) of an access point times a factor that is a function of the number of overlapping cells. Periodic contention-free sessions (PCFSs) are generated, one from each overlapping cell. PCFS transmission attempts occur at the fixed specified time spacing following the start of the previous cycle. Each active AP sets a timer at CP and a PCFS is initiated when the timer expires. The timer is then reset to CP and this starts a new cycle. Contention transmissions are attempted by stations based on their assigned priority. If a channel is busy at the designated start time for transmitting a PCFS, the PCFS is shortened by the time lost. Interleaving PCFSs and CFSs reduces conflicts with CFSs from other cells. To lessen the contention between APs of different cells, each station's Network Allocation Vector (NAV) and Inter-BSS Network Allocation Vector (IBNAV) is updated by an increased value of the next CFS length, the increment being the inter-BSS contention period (IBCP). APs will attempt to access the channel during the IBCP only for transmitting a PCFS, while they will wait for the NAV and IBNAV expirations before attempting to transmit a CFS. Interleaving PCFSs and CFSs also enables maintaining quality of service (QoS).

Abstract translation: 用于周期性无争用会话（PCFS）的访问方法减少了在相同介质上竞争的重叠的第一和第二无线LAN单元之间的干扰。 每个小区包括相应的多个成员站和接入点（AP）站。 定期无竞争会话（PCFS）的访问方法包括一个固定的周期时间，可以减少与其他单元的PCFS冲突。 来自几个小区的PCFS以循环周期（CP）的周期重复，循环周期（CP）是接入点的无争用周期（CFP）乘以作为重叠小区数的函数的因子。 生成定期无竞争会话（PCFS），每个重叠的单元格之一。 在上一个周期开始之后，固定的指定时间间隔发生PCFS传输尝试。 每个活动AP在CP处设置定时器，并且当定时器到期时启动PCFS。 然后定时器复位到CP，并启动一个新的周期。 根据其分配的优先级，站点尝试竞争传输。 如果信道在指定的启动时间忙于发送PCFS，则PCFS将被丢失的时间缩短。 交叉PCFS和CFS减少与其他单元格的CFS的冲突。 为了减少不同小区的AP之间的争用，每个站的网络分配向量（NAV）和BSS间网络分配向量（IBNAV）通过增加下一个CFS长度的值来更新，该增量是BSS间争用周期（ IBCP）。 AP将尝试在IBCP期间访问该信道，仅用于发送PCFS，同时在尝试发送CFS之前等待NAV和IBNAV到期。 交互式PCFS和CFS还可以保持服务质量（QoS）。

公开(公告)号：US20030174664A1

公开(公告)日：2003-09-18

申请号：US10256309

申请日：2002-09-27

Applicant: AT&T Corp.

Inventor： Mathilde Benveniste

IPC: H04B007/185

CPC classification number: H04W24/04 ,  H04W56/00 ,  H04W74/02 ,  H04W74/0808 ,  H04W84/12

Abstract: An access point transmits a preemptive peg packet when it has no data to transmit in order to maintain the contiguity of its transmission timing position with respect to the timing position of other contention-free sessions (CFS) transmitted by other access points in an existing, periodic sequence. The cyclic prioritized multiple access (CPMA) method establishes the transmission timing position of contention-free sessions (CFS) between overlapping first and second wireless LAN cells contending for the same medium. Each cell includes a respective plurality of member stations. If an access point has no traffic, it will transmit a short, preemptive pegging packet and reset its backoff timer. In this manner, no gaps longer than the distributed coordination function (DCF) Interframe Space (DIFS) are left idle. This prevents other stations from using DCF contention to seize the channel, until all access points have completed one contention-free session (CFS) per periodic cycle.

Abstract translation: 接入点当其没有数据要发送时，发送预抢占分组，以便保持其传输定时位置相对于其他接入点在现有的其他接入点中发送的其他无争用会话（CFS）的定时位置的邻接性， 周期性序列。 循环优先多重访问（CPMA）方法建立在相同媒体竞争的重叠的第一和第二无线LAN小区之间的无争用会话（CFS）的传输定时位置。 每个小区包括相应的多个成员站。 如果接入点没有流量，它将传输一个短暂的抢占分组，并重置其退避定时器。 以这种方式，没有比分布式协调功能（DCF）帧间间隔（DIFS）长的间隙空闲。 这样可以防止其他站点使用DCF争用占用信道，直到所有接入点每周期周期完成一个无争用会话（CFS）。

公开(公告)号：US20030012166A1

公开(公告)日：2003-01-16

申请号：US10187132

申请日：2002-06-28

Applicant: AT&T Corp.

Inventor： Mathilde Benveniste

IPC: H04Q007/24

CPC classification number: H04W72/082 ,  H04W56/00 ,  H04W72/1231 ,  H04W74/02 ,  H04W74/06 ,  H04W84/12

Abstract: A method and system reduce interference between overlapping first and second wireless LAN cells in a medium. Each cell includes a respective plurality of member stations and there is at least one overlapped station occupying both cells. An inter-cell contention-free period value is assigned to a first access point station in the first cell, associated with an accessing order in the medium for member stations in the first and second cells. The access point transmits a beacon packet containing the inter-cell contention-free period value, which is intercepted at the overlapped station. The overlapped station forwards the inter-cell contention-free period value to member stations in the second cell. A second access point in the second cell can then delay transmissions by member stations in the second cell until after the inter-cell contention-free period expires. The beacon packet sent by the first access point station also includes an intra-cell contention-free period value, which causes the member stations in the first cell to delay accessing the medium until polled by the first access point. After the expiration of the intra-cell contention-free period, member stations in the first cell may contend for the medium based on the quality of service (QoS) data they are to transmit, using the Tiered Contention Multiple Access (TCMA) protocol.

公开(公告)号：US20040095911A1

公开(公告)日：2004-05-20

申请号：US10256305

申请日：2002-09-27

Applicant: AT&T Corp.

Inventor： Mathilde Benveniste ,  AT?amp;T CORP.

IPC: H04Q007/24

CPC classification number: H04W74/02 ,  H04L47/14 ,  H04L47/2416 ,  H04W16/14 ,  H04W56/00 ,  H04W74/0816 ,  H04W84/12

Abstract: A cyclic prioritized multiple access (CPMA) method is disclosed which includes Fixed Deterministic Post-Backoff. Fixed deterministic post-backoff reduces conflicts between access points of overlapping cells. Contention-free sessions (CFSs) can be generated, one from each overlapping cell. Each active access point engages in a fixed deterministic post-backoff. A fixed deterministic backoff delay (Bkoff times a fixed number of idle time slots) is used by all access points, with the value of Bkoff being greater than the number of overlapping cells. The Bkoff should be large enough to enable the traffic that needs to be accommodated by the channel. Each access point has a backoff timer that is counted down using the shortest interframe space possible, typically the Priority Interframe Space (PIFS). A contention-free session (CFS) is initiated when the backoff timer expires, and it is then reset to the value of Bkoff to start a new cycle. A cycle is measured in terms of idle time slots instead of a fixed time interval. Contention-based transmissions can be attempted by an access point or other stations in the cell using their assigned priority while the access point is counting down its backoff timer. A new access point can get started and resolve possible collisions by a small random backoff. Subsequent contention-free sessions (CFSs) will not conflict, given an existing sequence of non-conflicting CFSs, since the follower access point's backoff delay exceeds that of the leader's by at least one times the fixed number of idle time slots. In this manner, contention-free sessions can be conducted without interference in the first and second cells.

Abstract translation: 公开了一种循环优先多重访问（CPMA）方法，其包括固定的确定性后退。 固定的确定性后回退减少了重叠单元的接入点之间的冲突。 可以生成无竞争会话（CFS），每个重叠的单元格之一。 每个活动接入点都采用固定的确定性后补偿。 所有接入点使用固定的确定性退避延迟（Bkoff乘以固定数量的空闲时隙），其中Bkoff的值大于重叠小区的数量。 Bkoff应该足够大，以使通道需要容纳的流量。 每个接入点都有一个退避定时器，可以使用尽可能短的帧间间隔（通常为优先级帧间间隔（PIFS））进行倒计时。 当退避定时器到期时，启动无竞争会话（CFS），然后将其重新设置为Bkoff的值以开始新的周期。 以空闲时隙而不是固定的时间间隔来测量周期。 基于竞争的传输可以由小区中的接入点或其他站使用其分配的优先级来尝试，而接入点对其退避定时器进行倒计时。 一个新的接入点可以开始，并通过小的随机退避来解决可能的冲突。 考虑到现有的非冲突CFS序列，随后的无争用会话（CFS）将不会发生冲突，因为跟随者接入点的退避延迟超过了领导者的固定数量的空闲时隙的至少一倍。 以这种方式，可以在没有干扰的情况下进行无竞争会话在第一和第二小区中。

公开(公告)号：US20030181204A1

公开(公告)日：2003-09-25

申请号：US10256471

申请日：2002-09-27

Applicant: AT&T Corp.

Inventor： Mathilde Benveniste

IPC: H04Q007/20

CPC classification number: H04W74/02 ,  H04W56/00 ,  H04W74/0808 ,  H04W84/12

Abstract: A staggered startup method and system for a cyclic prioritized multiple access (CPMA) system reduce interference between overlapping first and second wireless LAN cells contending for the same medium. Each cell includes a respective plurality of member stations. A first member station in the first cell coordinates a periodic sequence of first contention-free sessions. Each contention-free session includes multiple bursts with other member stations in the first cell. The first member station retains control of the medium by using interframe spaces sufficiently short between the bursts so that the multiple bursts appear to contending stations to be a single instance of activity in the medium during a session until an end of a session. A second member station in the second cell listens to the activity in the medium and detects an end to one of the first contention-free sessions indicated by an interval longer than a PIFS idle interval following an end to the activity in the medium. The second member station then sets a post-backoff delay to periodically transmit a minimal interval after the first contention-free sessions of the first member station. The second member station coordinates in the second cell a periodic sequence of second contention-free sessions. In this manner, contention-free sessions are interleaved on a periodic basis in the first and second cells.

Abstract translation: 用于循环优先多址（CPMA）系统的交错启动方法和系统降低了竞争相同介质的重叠的第一和第二无线LAN小区之间的干扰。 每个小区包括相应的多个成员站。 第一个小区中的第一个成员站协调第一个无竞争会话的周期性序列。 每个无争用会话包括与第一个小区中的其他成员站的多个突发。 第一成员站通过使用在突发之间足够短的帧间空间来保持对介质的控制，使得多个突发似乎将竞争站看作是在会话期间的介质中的单个活动实例，直到会话结束。 第二小区中的第二成员站监听介质中的活动，并且检测到在介质中的活动结束之后由比PIFS空闲间隔更长的间隔指示的第一无竞争会话之一的结束。 然后，第二成员站设置回退后延迟，以在第一成员站的第一无争用会话之后周期性地发送最小间隔。 第二成员站在第二小区中协调第二无竞争会话的周期性序列。 以这种方式，无竞争会话在第一和第二小区中被周期性地交织。