Fixed wireless loop system that ranks non-assigned PN codes to reduce
interference
    1.
    发明授权
    Fixed wireless loop system that ranks non-assigned PN codes to reduce interference 失效
    固定无线环路系统,排列未分配的PN码以减少干扰

    公开(公告)号:US6023462A

    公开(公告)日:2000-02-08

    申请号:US988413

    申请日:1997-12-10

    摘要: Disclosed is a method for operating a fixed wireless system (FWS) having a radio base unit (RBU) that uses a code division multiple access (CDMA) airlink for communicating with a plurality of subscriber units (SUs) within a coverage area of the RBU. The method includes establishing, from a set of pseudonoise (PN) spreading codes, a subset of PN spreading codes that are currently assigned to SUs and a subset of PN spreading codes that are currently not assigned to SUs. The method further ranks the PN spreading codes from the subset of non-assigned PN spreading codes by an amount of interference experienced by the use of each non-assigned PN spreading code, and assigns to an SU requiring a PN spreading code a PN spreading code from the set of non-assigned PN spreading codes that is ranked as having a least amount of interference. The step of ranking the non-assigned PN spreading codes is preferably performed periodically, and includes the steps of assigning, in turn, individual ones of the PN spreading codes from the set of non-assigned PN spreading codes to a correlator of the RBU, and determining an amount of noise output from the correlator resulting from the use of the PN spreading code.

    摘要翻译: 公开了一种用于操作具有无线电基站单元(RBU)的固定无线系统(FWS)的方法,该无线电基站单元(RBU)使用码分多址(CDMA)空中链路来与RBU的覆盖区域内的多个用户单元(SU)进行通信 。 该方法包括从一组伪噪声(PN)扩展码建立当前分配给SU的PN扩展码的子集和当前未分配给SU的PN扩展码的子集。 该方法将PN扩展码从未分配的PN扩展码的子集排列为使用每个未分配的PN扩展码所经历的干扰量,并且分配给需要PN扩展码的PN扩频码 从被排列为具有最小干扰量的未分配PN扩展码的集合。 对未分配的PN扩展码进行排序的步骤优选地周期性地进行,并且包括以下步骤:将PN扩展码中的各个PN扩展码从所述一组未分配的PN扩展码分配给所述RBU的相关器, 以及确定从使用PN扩展码产生的相关器输出的噪声量。

    Fixed wireless loop system having adaptive system capacity based on
estimated signal to noise ratio
    2.
    发明授权
    Fixed wireless loop system having adaptive system capacity based on estimated signal to noise ratio 失效
    基于估计信噪比的具有自适应系统容量的固定无线环路系统

    公开(公告)号:US6061339A

    公开(公告)日:2000-05-09

    申请号:US988074

    申请日:1997-12-10

    IPC分类号: H04B17/00 H04B7/216 H04Q7/00

    CPC分类号: H04B17/336

    摘要: A method is disclosed for operating a fixed wireless system having a radio base unit (RBU) that uses a code division multiple access (CDMA) airlink for communicating with a plurality of subscriber units (SUs). The method includes steps of (a) estimating a signal to noise ratio (SNR) of the FWS; (b) comparing the estimated SNR to a threshold SNR value; and (c) one of allowing service to another SU or not allowing service to another SU based on the result of the step of comparing. The step of estimating preferably uses a normalized SNR, and further employs the use of a null PN code detection technique. More particularly, the step of estimating determines a normalized signal to noise ratio given by Eb/No=20 log (SUT/MUT)-xdB, wherein SUT represents a single user test measurement, wherein MUT represents a multiple user test measurement, and wherein xdB is an adjustment factor. Other types of CDMA systems may also use this technique.

    摘要翻译: 公开了一种用于操作具有无线电基站单元(RBU)的固定无线系统的方法,其使用码分多址(CDMA)空中链路来与多个用户单元(SU)进行通信。 该方法包括以下步骤:(a)估计FWS的信噪比(SNR); (b)将估计的SNR与阈值SNR值进行比较; 以及(c)基于比较步骤的结果,允许对另一个SU的服务或不允许服务于另一个SU的一个。 估计的步骤优选地使用归一化的SNR,并且还采用空PN码检测技术的使用。 更具体地,估计步骤确定由Eb / No = 20log(SUT / MUT)-xdB给出的归一化信噪比,其中SUT表示单用户测试测量,其中MUT表示多用户测试测量,并且其中 xdB是一个调整因子。 其他类型的CDMA系统也可以使用这种技术。

    Synchronizer and method therefor and communications system incorporating same
    4.
    发明授权
    Synchronizer and method therefor and communications system incorporating same 失效
    同步器及其方法及其结合的通信系统

    公开(公告)号:US06332008B1

    公开(公告)日:2001-12-18

    申请号:US09170018

    申请日:1998-10-13

    IPC分类号: H04L700

    CPC分类号: H04B1/7085

    摘要: Users or subscribers of a spread spectrum synchronous communications system provide signals to the central station or base unit of that system, and receive signals therefrom. Proper synchronization among those users (and their signals) is needed to ensure proper operation of the system. To ensure proper synchronization among those users, the signal produced by each user is checked for presence and amount of any offset error. This is accomplished by using three despreaders for the signal for each user. For one such user, each such despreader for that user receives the spreading code for that user. However, the spreading code as received by any one such despreader is time-delayed with respect to the spreading code as received by the other two despreaders. Each such despreader receives the spreading code with a different amount of delay imposed on that spreading code. The outputs of the three despreaders are digitally combined (e.g. compared), or compared, to produce the offset estimate for that user. To reduce noise effects, the offset estimate is averaged over a predetermined time duration; alternatively, such averaging can be performed on the outputs of the despreaders, or at some intermediate processing step. The offset estimate is sent to the user, to be used to correct synchronization of that user. Offset estimates that are too small to be useful are squelched and are not so sent to the user, to reduce channel usage and thereby save bandwidth.

    摘要翻译: 扩频同步通信系统的用户或用户向该系统的中心站或基站提供信号,并从其接收信号。 需要这些用户(及其信号)之间的正确同步,以确保系统的正常运行。 为了确保这些用户之间的正确同步,检查每个用户产生的信号是否存在和任何偏移量错误的量。 这是通过使用三个解扩器为每个用户的信号来实现的。 对于一个这样的用户,用于该用户的每个这样的解扩器接收该用户的扩展码。 然而,由任何一个这样的去扩展器接收的扩展码相对于由其他两个解扩器接收到的扩展码是时间延迟的。 每个这样的解扩器以不同的延迟量来接收扩展码。 三个解扩器的输出被数字组合(例如比较)或比较,以产生该用户的偏移估计。 为了减少噪声影响,偏移估计在预定的持续时间内被平均化; 或者,可以对解扩器的输出执行这样的平均,或者在一些中间处理步骤。 偏移估计被发送给用户,用于纠正该用户的同步。 偏移估计太小而无法用于压缩,不会发送给用户,以减少通道使用率,从而节省带宽。

    Synchronizer and method therefor and communications system incorporating
same
    5.
    发明授权
    Synchronizer and method therefor and communications system incorporating same 失效
    同步器及其方法及其结合的通信系统

    公开(公告)号:US5867525A

    公开(公告)日:1999-02-02

    申请号:US872398

    申请日:1997-06-10

    CPC分类号: H04B1/7085

    摘要: Users or subscribers of a spread spectrum synchronous communications system provide signals to the central station or base unit of that system, and receive signals therefrom. Proper synchronization among those users (and their signals) is needed to ensure proper operation of the system. To ensure proper synchronization among those users, the signal produced by each user is checked for presence and amount of any offset error. This is accomplished by using three despreaders for the signal for each user. For one such user, each such despreader for that user receives the spreading code for that user. However, the spreading code as received by any one such despreader is time-delayed with respect to the spreading code as received by the other two despreaders. Each such despreader receives the spreading code with a different amount of delay imposed on that spreading code. The outputs of the three despreaders are digitally combined (e.g. compared), or compared, to produce the offset estimate for that user. To reduce noise effects, the offset estimate is averaged over a predetermined time duration; alternatively, such averaging can be performed on the outputs of the despreaders, or at some intermediate processing step. The offset estimate is sent to the user, to be used to correct synchronization of that user. Offset estimates that are too small to be useful are squelched and are not so sent to the user, to reduce channel usage and thereby save bandwidth.

    摘要翻译: 扩频同步通信系统的用户或用户向该系统的中心站或基站提供信号,并从其接收信号。 需要这些用户(及其信号)之间的正确同步,以确保系统的正常运行。 为了确保这些用户之间的正确同步,检查每个用户产生的信号是否存在和任何偏移量错误的量。 这是通过使用三个解扩器为每个用户的信号来实现的。 对于一个这样的用户,用于该用户的每个这样的解扩器接收该用户的扩展码。 然而,由任何一个这样的去扩展器接收的扩展码相对于由其他两个解扩器接收到的扩展码是时间延迟的。 每个这样的解扩器以不同的延迟量来接收扩展码。 三个解扩器的输出被数字组合(例如比较)或比较,以产生该用户的偏移估计。 为了减少噪声影响,偏移估计在预定的持续时间内被平均化; 或者,可以对解扩器的输出执行这样的平均,或者在一些中间处理步骤。 偏移估计被发送给用户,用于纠正该用户的同步。 偏移估计太小而无法用于压缩,不会发送给用户,以减少通道使用率,从而节省带宽。

    Data scrambling system and method and communications system
incorporating same
    7.
    发明授权
    Data scrambling system and method and communications system incorporating same 失效
    数据加扰系统及其相结合的方法和通信系统

    公开(公告)号:US5917852A

    公开(公告)日:1999-06-29

    申请号:US873538

    申请日:1997-06-11

    CPC分类号: H04B1/707

    摘要: Users or subscribers of a multi-user communications system, such as a spread spectrum communications system, provide signals to the central station or base unit of that system, and receive signals therefrom. Avoidance of interference among those users' signals is needed to ensure proper operation of the system. To do so, the data of each user is individually scrambled to randomize the data that different users are transmitting, in order to improve tracking performance at a receiver. The data of each user is scrambled independently, in a manner unique to that user in the system, in order to improve tracking performance and detection performance of a receiver. This scrambling makes the multi-user interference zero mean, and makes it possible to integrate out or average out the multi-user interference. The pattern or sequence used for this scrambling, and the pattern or sequence used for spreading here, are preferably identical except in frequency.

    摘要翻译: 诸如扩频通信系统的多用户通信系统的用户或用户向该系统的中心站或基站提供信号,并从其接收信号。 需要避免用户信号之间的干扰,以确保系统的正常运行。 为了这样做,每个用户的数据被单独加扰以随机化不同用户正在发送的数据,以便提高接收机的跟踪性能。 为了提高接收机的跟踪性能和检测性能,每个用户的数据以系统中该用户唯一的方式独立地加扰。 这种扰乱使得多用户干扰为零是平均的,并且使得可以整合或平衡多用户干扰。 用于该扰频的模式或序列以及用于在此扩展的模式或序列优选地在频率以外是相同的。