Abstract:
An embodiment of the present invention provides a method, comprising dynamically reserving free channel time blocks for directional transmissions in a wireless personal area network (WPAN) by a transceiver communicating with a Coordinator and the Coordinator allocating a part or a whole of unreserved channel time blocks for a directional link during a handshake with the transceiver.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority to U.S. Provisional Patent Application Ser. No. 61/035,480, filed Mar. 11, 2008, by Li et al. entitled, “60 GHZ WPAN MAC AND PHY FEATURES”. 
     
    
     BACKGROUND 
       [0002]    The availability of 7 GHz of unlicensed spectrum in the 60 GHz band offers the potential for multi-Gigabit indoor wireless personal area networking (WPAN). Applications that require large bandwidth include uncompressed High Definition (HD) video streaming, fast file download from an airport kiosk (Sync &amp; Go) and wireless display and docking, to name just a few. These applications cannot be supported over existing home networking solutions (IEEE 802.11 a/b/g/n and WiMedia UWB) because the required data rates far exceed the capabilities of these networks. 
         [0003]    Thus, a strong need exists for improvements and new development in wireless personal area networks that operate in the 60 GHz band. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which: 
           [0005]      FIG. 1  provides an example of a super-frame schedule of an embodiment of the invention; 
           [0006]      FIG. 2  provides a dynamic bandwidth reservation example an embodiment of the invention; and 
           [0007]      FIG. 3  illustrates a dynamic bandwidth reservation flow according to an embodiment of the present invention. 
       
    
    
       [0008]    It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding or analogous elements. 
       DETAILED DESCRIPTION 
       [0009]    In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the preset invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention. 
         [0010]    In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, units and/or circuits have not been described in detail so as not to obscure the invention. 
         [0011]    Although embodiments of the invention are not limited in this regard, discussions utilizing terms such as, for example, “processing,” “computing,” “calculating,” “determining,” “establishing”“analyzing”, “checking”, or the like, may refer to operation(s) and/or process(es) of a computer, a computing platform, a computing system, or other electronic computing device, that manipulate and/or transform data represented as physical (e.g., electronic) quantities within the computer&#39;s registers and/or memories into other data similarly represented as physical quantities within the computer&#39;s registers and/or memories or other information storage medium that may store instructions to perform operations and/or processes. 
         [0012]    Although embodiments of the invention are not limited in this regard, the terms “plurality” and “a plurality” as used herein may include, for example, “multiple” or “two or more”. The terms “plurality” or “a plurality” may be used throughout the specification to describe two or more components, devices, elements, units, parameters, or the like. For example, “a plurality of stations” may include two or more stations. 
         [0013]    A millimeter (mm) wave communication link imposes more challenges in terms of link budget than those at lower frequencies (e.g. 2.4 GHz and 5 GHz bands) because of its inherent isolation due to both oxygen absorption, which attenuates the signal over long range, and its short wavelength, which provides high attenuation through obstructions such as walls and ceilings. In many cases, it is preferable to employ directional antennas for high-speed point-to-point data transmission. Devices performing directional transmissions can achieve higher range (mitigation for the link budget issue), as well as better aggregated throughput and spatial reuse, whereas certain pairs of devices separated in space can communicate simultaneously. A directional antenna pattern covering a wide range of angles to give omni-directional coverage may be employed to aid in neighbor discovery and beam-steering decisions. Furthermore, the antennae supported by devices can be of several types: Non-Trainable Antenna, Sectorized Antenna or Phased Array Antenna. 
         [0014]    In a traditional 60 GHz WPAN, the channel time is scheduled using Time Division Multiple Access (TDMA) technology that does not support parallel transmissions. As seen in  FIG. 1 , generally shown as  100 , channel time reservations are usually performed for each super-frame  110 ,  120  and  130  (the basic timing division for TDMA) by the Coordinator and communicated in the beacon frame  150 . If a channel time block is reserved  160  for a specific pair of devices then the sender performs high-rate directional transmission. At the same time, if the channel time block is unreserved  170 , it can be accessed using the CSMA (Carrier Sense Multiple Access) mechanism. Unfortunately, the CSMA mechanism necessitates using omni-directional transmissions that are rather inefficient and provide very low throughput. The existing medium access control (MAC) protocols allow reserving channel time blocks only starting from the next super-frame after the new schedule has been announced in the beacon  150 . That incurs large delays for bursty data traffic, which adversely affects the application performance. On the other hand, reserving spare channel time for such traffic leads to poor channel utilization. An embodiment of the present invention provides a mechanism for dynamic reservation of free channel time blocks for directional transmission, which reduces the latency and increases the throughput of bursty data traffic. 
         [0015]    As shown in  FIG. 2  at  200 , an embodiment of the present invention provides a novel mechanism for dynamic reservation of free channel time blocks for directional transmission. Superframes are shown at  210 ,  220  and  230  with superframe  220  called out at  240  and including beacon  250 , reserved block  260 , handshake  270  and dynamically reserved block  280 . During handshaking  270  with the sender, the Coordinator allocates a part or the whole unreserved channel time block for a directional link. The bandwidth allocation request specifying the reservation period is sent by the sender using omni-directional or directional transmission pointed toward the Coordinator. The Coordinator responds to the sender using (quasi) omni-directional transmission that must be received by the other devices with the bandwidth grant message that specifies the allocated reservation period, which can be less than or equal to that in the bandwidth allocation request. In embodiment of the present invention, but not limited in this respect, the Coordinator may also allow certain non-interfering links to utilize the allocated channel time block as specified in the bandwidth grant message. 
         [0016]    Looking now at  FIG. 3  at  300 , the message flow of the proposed mechanism is provided including receiver  310 , sender  320  and coordinator  330 . At  340  bandwidth request  340  is sent from sender  320  to coordinator  330  with a BW grant from coordinator to sender at  350 . At  360  sender transmits (directional) data  360  to receiver  310 . Further, in an embodiment of the present invention, the sender may itself act as the Coordinator and may need to just announce the grant. 
         [0017]    As illustrated herein, embodiments of the present invention increase the throughput and decrease the latency for bursty data traffic. Further, the present invention maintains high channel utilization in presence of bursty data traffic and provides efficient channel sharing with constant and variable bit rate connections. It may also provide techniques for efficient spatial reuse and increases the capacity and the overall throughput of a WPAN. 
         [0018]    While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents may occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.