Patent Publication Number: US-2016233940-A1

Title: Wireless device, method, and computer readable media for spatial reuse in a high efficiency wireless local-area network

Description:
PRIORITY CLAIM 
     This application claims the benefit of priority under 35 USC 119(e) to U.S. Provisional Patent Application Ser. No. 62/113,040, filed Feb. 6, 2015, which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments pertain to wireless communications in a wireless local-area network (WLAN). Some embodiments relate to spatial reuse for device-to-device (D2D) communication. Some embodiments relate to Institute of Electrical and Electronic Engineers (IEEE) 802.11 and some embodiments relate to IEEE 802.11 ax. Some embodiments relate to a transmitter using uplink or downlink OFDMA and/or MU-MIMO signaling information to enable another transmitter to spatially reuse the wireless medium. Some embodiments relate to a transmitter determining a spatial reuse opportunity and adjusting parameters to enable spatial reuse. 
     BACKGROUND 
     Users of wireless networks often demand more bandwidth and faster response times. However, the available bandwidth may be limited. One issue in wireless local area networks (WLANs) is that the wireless devices may be close to each other and operating with different master stations or access points (APs). As wireless communication has become more and more popular there are more and more devices operating close to one another. 
     Thus, there are general needs for systems and methods for efficiently using the wireless medium, and in particularly, using the wireless medium when wireless devices may be close to one another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a WLAN in accordance with some embodiments; 
         FIG. 2  illustrates a method of determining interference in accordance with some embodiments; 
         FIG. 3  illustrates a method of determining interference in accordance with some embodiments; 
         FIG. 4  illustrates a method for spatial reuse for device-to-device links in accordance with some embodiments; 
         FIG. 5  illustrates a frame for a wireless device to send a spatial reuse indication  506  in accordance with some embodiments; 
         FIG. 6  illustrates an exchange where a frame may include a spatial reuse indication in accordance with some embodiments; 
         FIG. 7  illustrates an exchange where a frame may include a spatial reuse indication in accordance with some embodiments; 
         FIG. 8  illustrates a spatial reuse indication that comprises a margin field in accordance with some embodiments; 
         FIG. 9  illustrates a margin field that includes additional interference subfield, current interference level subfield, and TX power subfield; 
         FIG. 10  illustrates a margin field that includes tolerable interference level subfield and TX power  1004  subfield; 
         FIG. 11  illustrates a margin field that includes a tolerable interference level plus TX power subfield; 
         FIG. 12  illustrates the margin as an additional interference above an average interference level; 
         FIG. 13  illustrates the margin as a tolerable interference level above a base threshold; 
         FIG. 14  illustrates a TX wireless device with three RX wireless devices linked to the TX wireless device in accordance with some embodiments; 
         FIG. 15  illustrates a method of spatial reuse in accordance with some embodiments; 
         FIG. 16  illustrates a method for uplink spatial reuse in accordance with some embodiments; 
         FIG. 17  illustrates an example where a receiver may identify the D2D links in accordance with some embodiments; 
         FIG. 18  illustrates a method for uplink spatial reuse in accordance with some embodiments; 
         FIG. 19  illustrates two links in accordance with some embodiments; 
         FIG. 20  illustrates the two links illustrated in  FIG. 19  with signal strengths in accordance with some embodiments; 
         FIG. 21  illustrates a HEW device in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims. 
       FIG. 1  illustrates a WLAN  100  in accordance with some embodiments. The WLAN may comprise a basis service set (BSS)  100  that may include a master station  102 , which may be an AP, a plurality of high-efficiency wireless (HEW) (e.g., IEEE 802.1 lax) STAs  104  and a plurality of legacy (e.g., IEEE 802.11n/ac) devices  106 . 
     The master station  102  may be an AP using the IEEE 802.11 to transmit and receive. The master station  102  may be a base station. The master station  102  may use other communications protocols as well as the IEEE 802.11 protocol. The IEEE 802.11 protocol may be IEEE 802.11ax. The IEEE 802.11 protocol may include using OFDMA, time division multiple access (TDMA), and/or code division multiple access (CDMA). The IEEE 802.11 protocol may include a multiple access technique. For example, the IEEE 802.11 protocol may include space-division multiple access (SDMA) and/or MU-MIMO. 
     The legacy devices  106  may operate in accordance with one or more of IEEE 802.11 a/g/ag/n/ac, IEEE 802.11-2012, or another legacy wireless communication standard. The legacy devices  106  may be STAs or IEEE STAs. 
     The HEW STAs  104  may be wireless transmit and receive devices such as cellular telephone, handheld wireless device, wireless glasses, wireless watch, wireless personal device, tablet, or another device that may be transmitting and receiving using the IEEE 802.11 protocol such as IEEE 802.11ax or another wireless protocol. In some embodiments, the HEW STAs  104  may be termed high efficiency (HE) stations. 
     The BSS  100  may operate on a primary channel and one or more secondary channels or sub-channels. The BSS  100  may include one or more master stations  102 . In accordance with some embodiments, the master station  102  may communicate with one or more of the HEW devices  104  on one or more of the secondary channels or sub-channels or the primary channel. In accordance with some embodiments, the master station  102  communicates with the legacy devices  106  on the primary channel. In accordance with some embodiments, the master station  102  may be configured to communicate concurrently with one or more of the HEW STAs  104  on one or more of the secondary channels and a legacy device  106  utilizing only the primary channel and not utilizing any of the secondary channels. 
     The master station  102  may communicate with legacy devices  106  in accordance with legacy IEEE 802.11 communication techniques. In example embodiments, the master station  102  may also be configured to communicate with HEW STAs  104  in accordance with legacy IEEE 802.11 communication techniques. Legacy IEEE 802.11 communication techniques may refer to any IEEE 802.11 communication technique prior to IEEE 802.11 ax. 
     In some embodiments, a HEW frame may be configurable to have the same bandwidth as a sub-channel, and the bandwidth may be one of 20 MHz, 40 MHz, or 80 MHz, 160 MHz, 320 MHz contiguous bandwidths or an 80+80 MHz (160 MHz) non-contiguous bandwidth. In some embodiments, bandwidths of 1 MHz, 1.25 MHz, 2.0 MHz, 2.5 MHz, 5 MHz and 10 MHz, or a combination thereof or another bandwidth that is less or equal to the available bandwidth, may also be used. A HEW frame may be configured for transmitting a number of spatial streams, which may be in accordance with MU-MIMO. 
     In other embodiments, the master station  102 , HEW STA  104 , and/or legacy device  106  may also implement different technologies such as code division multiple access (CDMA)  2000 , CDMA 2000 1×, CDMA 2000 Evolution-Data Optimized (EV-DO), Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Long Term Evolution (LTE), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), BlueTooth®, or other technologies. 
     Some embodiments relate to HEW communications. In accordance with some IEEE 802.11 ax embodiments, a master station  102  may operate as a master station which may be arranged to contend for a wireless medium (e.g., during a contention period) to receive exclusive control of the medium for an HEW control period. In some embodiments, the HEW control period may be termed a transmission opportunity (TXOP). The master station  102  may transmit a HEW master-sync transmission, which may be a trigger frame or HEW control and schedule transmission, at the beginning of the HEW control period. The master station  102  may transmit a time duration of the TXOP and sub-channel information. During the HEW control period, HEW STAs  104  may communicate with the master station  102  in accordance with a non-contention based multiple access technique such as OFDMA or MU-MIMO. This is unlike conventional WLAN communications in which devices communicate in accordance with a contention-based communication technique, rather than a multiple access technique. During the HEW control period, the master station  102  may communicate with HEW stations  104  using one or more HEW frames. During the HEW control period, the HEW STAs  104  may operate on a sub-channel smaller than the operating range of the master station  102 . During the HEW control period, legacy stations refrain from communicating. In accordance with some embodiments, during the master-sync transmission the HEW STAs  104  may contend for the wireless medium with the legacy devices  106  being excluded from contending for the wireless medium during the master-sync transmission. 
     In some embodiments, the multiple-access technique used during the HEW control period may be a scheduled OFDMA technique, although this is not a requirement. In some embodiments, the multiple access technique may be a time-division multiple access (TDMA) technique or a frequency division multiple access (FDMA) technique. In some embodiments, the multiple access technique may be a space-division multiple access (SDMA) technique. 
     The master station  102  may also communicate with legacy stations  106  and/or HEW stations  104  in accordance with legacy IEEE 802.11 communication techniques. In some embodiments, the master station  102  may also be configurable to communicate with HEW stations  104  outside the HEW control period in accordance with legacy IEEE 802.11 communication techniques, although this is not a requirement. 
     In example embodiments, the HEW device and/or the master station  102  are configured to perform the methods and functions described in conjunction with  FIGS. 1-21  and disclosed herein such as generating, transmitting, receiving, and operating in accordance with signaling for a spatial reuse. 
       FIG. 2  illustrates a method of determining interference in accordance with some embodiments. Illustrated in  FIG. 2  are wireless devices  202 , links  204 , and interference  206 . The wireless devices  202 . 1  (RX),  202 . 2  (TX),  202 . 3  (RX),  202 . 4  (RX), and  202 . 5  (TX), may be an AP  102 , HEW device  104 , and/or a legacy device  106 . RX is an abbreviation for receiver, and TX is an abbreviation for transmitter. Link  204  may be D2D links. 
     Wireless device  202 . 2  may be a transmitting wireless device that is linked with wireless devices  202 . 1 ,  202 . 2 , and  202 . 3 . Link  204 . 1  is between wireless device  202 . 2  and wireless device  202 . 1 . Link  204 . 2  is between wireless device  202 . 2  and wireless device  202 . 4 . Link  204 . 3  is between wireless device  202 . 2  and wireless device  202 . 3 . 
     Interference  206 . 1 ,  206 . 2 ,  206 . 3 , and  206 . 4  are the interferences that wireless device  202 . 5  would cause to the wireless device  202 . 1 ,  202 . 2 ,  202 . 3 , and  202 . 4 , respectively, if wireless device  202 . 5  transmits. For example, if wireless device  202 . 5  transmits then interference  206 . 3  is the interference the transmission will cause to wireless device  202 . 3 . 
     In some embodiments the wireless devices  202 , which may be an AP  102  and/or HEW device  104 , are configured to approximate the interferences  206 . 4 ,  206 . 1 , and  206 . 3  with the interference  206 . 2 . In some embodiments the wireless devices  202  may approximate the interference  206  to a device linked  204  to another device by the interference  206  to the wireless device  202  it is linked to. For example, wireless device  202 . 5  may be configured to approximate the interference  206 . 1  that wireless device  202 . 5  will cause to wireless device  202 . 1  by the interference  206 . 2  that wireless device  202 . 5  will cause to wireless device  202 . 2 . 
     In some embodiments the wireless devices  202 , which may be an AP  102  and/or HEW device  104 , are configured to assume that all transmissions are OFDMA/MU-MIMO transmissions in both the uplink (UL) and downlink (DL) to simplify the interference measurements. 
       FIG. 3  illustrates a method of determining interference in accordance with some embodiments. Illustrated in  FIG. 3  are wireless devices  202 , links  204 , and interference  206 . The wireless devices  202 . 6  (RX),  202 . 7  (RX),  202 . 8  (RX) are new compared with  FIG. 2 . Wireless devices  202 . 6 ,  202 . 7 ,  202 . 8  are linked  202 . 4 ,  202 . 5 ,  202 . 6 , respectively, with wireless device  202 . 5 . 
     Wireless device  202 . 5  may measure interference  206 . 7 . Wireless device  202 . 5  may approximate the interference  206 . 2  ( FIG. 2 ) caused by wireless device  202 . 5  to wireless device  202 . 2  by interference  206 . 7 . The approximation of interference  206 . 2  by interference  206 . 7  may be determined more accurately if wireless device  202 . 5  knows the power that wireless device  202 . 2  used to transmit interference  206 . 7 . Wireless device  202 . 5  may then approximate the interference  206  to wireless device  202 . 3 ,  202 . 2 ,  202 . 4  that are linked  204  to wireless device  202 . 2  by the approximation of interference  206 . 2  by interference  206 . 7 . Wireless device  202 . 5  may approximate interference  206 . 2  by interference  206 . 7  and margin signaling from wireless device  202 . 2 . In some embodiments wireless device  202 . 5  may approximate interference  206 . 2  by interference  206 . 7  and reduction value of power control. 
       FIG. 4  illustrates a method  400  for spatial reuse for device-to-device links in accordance with some embodiments.  FIG. 4  will be described in conjunction with  FIGS. 5-15 .  FIGS. 6 and 7  illustrate margins  602 ,  702  in accordance with some embodiments. 
     The method begins at operation  402  with identify D2D links. D2D links are identified so that another link can potentially spatially reuse the same or an overlapping sub-channel or channel. The transmitter (TX) such as wireless device  202 . 2  ( FIGS. 2 and 3 ) may determine whether or not link  204 . 2  is a D2D link with wireless device  202 . 4 . 
     If the signal strength is high such as −36 dBm to −44 dBm for 1 meter to 3 meter distance, then the signal strength may be determined to be high. For example, the link  204 . 2  may be a D2D link. In some embodiments, a threshold value for signal strength is determined, and if the signal strength is higher than the threshold value, then the wireless device  202  may identify the link  204  as a D2D link. 
     In some embodiments, the wireless device  202  such as  202 . 4  measures the received signal strength and compares it with the threshold. If the signal strength is higher than the threshold, then the wireless device  202  may send this information to the wireless device  202  that transmitted the signal. For example, wireless device  202 . 4  may receive a transmission over link 1   204 . 2  from wireless device  202 . 2 . Wireless device  202 . 4  may measure the signal strength of the transmission and compare the signal strength with a threshold value. The wireless device  202 . 4  may then send a packet to the wireless device  202 . 2  that indicates that link  204 . 2  is a D2D link. For example, the wireless device  202 . 4  may indicate the link  204 . 2  is a D2D link with one bit in a field that may be unused in a frame such as an acknowledgement frame, a block acknowledgement frame, a clear-to-send frame, a control frame, or a management frame. 
     In some embodiments, the wireless device  202 . 2  may receive information regarding the signal strength of a transmission sent to another wireless device  202  such as  202 . 4  using link  204 . 2 . For example, the wireless device  202 . 4  may send the wireless device  202 . 2  a link measurement report regarding transmission over link  204 . 2  The wireless device  202 . 2  may have a threshold for the link margin, and if the link margin is greater than the threshold determine that the link  204 . 2  is a D2D link. 
     In some embodiments, a TX wireless device such as wireless device  202 . 2  may determine whether the link  204 . 2  is a D2D link based on the signal strength of feedback from a RX wireless device such as wireless device  202 . 4 . To determine the signal strength, the wireless device  202 . 2  needs the transmitting power used by the wireless device  202 . 4 . The wireless device  202 . 2  may receive the transmitting power used by the wireless device  202 . 4  from a report from the wireless device  202 . 4  such as a transmitter power control (TPC) report element in an action frame. In some embodiments the wireless device  202 . 2  or wireless device  202 . 4  may identify more than one link  204  as a D2D link. 
     The method  400  may continue at operation  404  with signal a spatial reuse indication in accordance with some embodiments. Operation  404  will be described in conjunction with  FIGS. 5-7 . 
       FIG. 5  illustrates a frame  500  for a wireless device  202  to send a spatial reuse indication  506  in accordance with some embodiments. Illustrated in  FIG. 5  is packet  500 . Time  512  is along the horizontal axis. The TX 1   510  is a wireless device  202  that transmits packet  500 . TX 2  identifies spatial reuse opportunity  508 . The packet  500  includes a first portion  502  that may be a preamble or MAC header  502  and remainder of packet  504 . The first portion  502  may include the spatial reuse indication  506 . The spatial reuse indication  506  may be part of a HE-SIG and/or a MAC header  502 . The spatial reuse indication  506  may be part of a HE-SIG-A, HE-SIG-B, and/or HE-SIG-C. The spatial reuse indication  506  may be a one bit signal that there is a spatial reuse opportunity. In some embodiments the spatial reuse indication  506  may be in a physical layer portion of the packet  500 . In some embodiments the spatial reuse indication  506  may use a margin field to indicate that a spatial reuse opportunity is available. For example, in some embodiments, the wireless device  202 . 2  may indicate a spatial opportunity is available if a margin field is greater than zero. The TX 2  may be a wireless device  202 . AT time  508  TX 2  may identify the spatial reuse opportunity after receiving the spatial reuse indication  506 . 
     An example of operation  404  is a TX wireless device such as wireless device  202 . 2  signaling a spatial reuse indication  506  ( FIG. 5 ) in a first portion of a packet that is received by wireless device  202 . 5 . The wireless device  202  may also signal information for spatial reuse in a separate frame exchange as described in  FIGS. 6 and 7 . 
       FIG. 6  illustrates an exchange  600  where a frame  602  may include a spatial reuse indication  506  in accordance with some embodiments. Illustrated in  FIG. 6  is time  610  along a horizontal axis and frames  702 ,  704 , and  706 . Frames  602  and  604  are transmitted by TX 1  and frame  604  is transmitted by RX 1 . TX 1  and RX 1  are wireless devices  202 . TX 1  may send a spatial reuse indication  506  in frame  602 . For example, wireless device  202 . 2  or  202 . 4  may exchange a frame with wireless device  202 . 5  that includes the spatial reuse indication  506 . The TX 2  may be a wireless device  202 . At time  608  TX 2  may identify the spatial reuse opportunity after receiving the spatial reuse indication  506 . 
       FIG. 7  illustrates an exchange  700  where a frame  704  may include a spatial reuse indication  506  in accordance with some embodiments. Illustrated in  FIG. 7  is time  710  along a horizontal axis and frames  702 ,  704 , and  706 . Frames  702  and  704  are transmitted by TX 1  and frame  704  is transmitted by RX 1 . TX 1  and RX 1  are wireless devices  202 . The wireless device  202  may signal information for spatial reuse in a separate frame exchange. For example, wireless device  202 . 4  may exchange a frame with wireless device  202 . 2  that includes the spatial reuse indication  506 . The TX 2  may be a wireless device  202 . At time  608  TX 2  may identify the spatial reuse opportunity after receiving the spatial reuse indication  506 . 
       FIG. 8  illustrates a spatial reuse indication  506  that comprises a margin  507  field in accordance with some embodiments.  FIG. 8  will be described in conjunction with  FIGS. 9-14 .  FIGS. 9-11  illustrate margin  900 ,  1000 ,  1100  fields, respectively, in accordance with some embodiments. 
       FIG. 9  illustrates a margin  900  field that includes additional interference  902  subfield, current interference level  904  subfield, and TX power  906  subfield. The additional interference  902  may be additional interference  1202  as described in conjunction with  FIG. 12 . The current interference level  904  may be a current or average interference level  1206  as described in conjunction with  FIG. 12 . The TX power  906  subfield may be the TX power  906  of the transmitter of the margin  900  field. 
       FIG. 10  illustrates a margin  1000  field that includes tolerable interference level  1002  subfield and TX power  1004  subfield. The tolerable interference level  1002  subfield may be a tolerable interference level  1302  as described in conjunction with  FIG. 13 . The TX power  1004  may be the TX power of the transmitter of the margin  1000  field. 
       FIG. 11  illustrates a margin  1100  field that includes a tolerable interference level plus TX power  1102  subfield. The tolerable interference level may be a tolerable interference level  1302  as described in conjunction with  FIG. 13 . The TX power may be the transmit power of the transmitter of the margin  1100  field. 
       FIG. 12  illustrates the margin  1202  as an additional interference above an average interference level  1206 . Illustrated in  FIG. 12  are M  1202 , tolerable interference level  1204 , average interference level  1206 , and base threshold  1206 . M  1202  is the margin. The average interference level  1206  may be an average amount of interference the TX has been experiencing. The average interference level  1206  may be determined based on feedback from the RX such as wireless device  202 . 6  ( FIGS. 2 and 3 ). The tolerable interference level  1204  may be an amount of interference the TX determines the TX can tolerate. In some embodiments, the tolerable interference level may be based on a MCS level. For example, the tolerable interference level  1204  may be an interference level that if reached or surpassed would mean the TX would switch to a lower MCS level. M  1202  may be the margin or amount of additional interference the TX may receive before reaching the tolerable interference level  1204 . 
       FIG. 13  illustrates the margin  1302  as a tolerable interference level  1304  above a base threshold  1306 . The base threshold  1306  may be a known threshold value. The tolerable interference level  1304  may be determined by the TX such as wireless device  202 . 5  ( FIG. 3 ) based on the TX&#39;s characteristics and/or recent communications of the TX. The tolerable interference level  1304  may be a known tolerable interference level  1304  for a particularly MCS the TX is using or intends to use. The margin (M)  1302  may indicate an additional interference that can be tolerated by the TX above the base threshold  1306 . 
     In some embodiments, the value of margin (M)  507 ,  900 ,  1000 ,  1100 ,  1202 , and  1302  may be signaled with 5 bits to indicate a value from 0 to 31 dB with 1 dB increments. In some embodiments, the value of M  507 ,  900 ,  1000 ,  1100 ,  1202 , and  1302  may be signaled with 4 bits to indicate a value from 0 to 30 dB with 2 dB increments. In some embodiments, some bits may indicate a base and some bits may indicate a multiplier such as M=base * multiplier. For example, 3 bits may be used to indicate a base from 0 to 7 and 2 bits may be used to indicate a multiplier where the multiplier may be one plus the binary number represented by the multiplier bits. In some embodiments, if a bit is used to indicate whether or not a D2D spatial reuse opportunity is available, the bits for the value of M  507 ,  900 ,  1000 ,  1100 ,  1202 , and  1302  may be ignored or absent if the bit indicates there is not a D2D spatial reuse opportunity. 
     The TX power  906 ,  1004  may be represented as a predefined unit. For example, 10 may indicate 10 mW. The TX power  906 ,  1004  may be represented based on a predefined unit and base. For example, 10 may indicate (10+base) mW, where the base may be a number such as 20. The TX power  906 ,  1004  may be represented based on a predefined unit and a relative value. For example, 10 may mean 10 dB compared to 1 mW, which would give 10 mW. In some embodiments, the TX power  906 ,  1004  may be determined by the master station  102 . In some embodiments, the transmit power may be determined by the wireless protocol such as IEEE 802.11ax. 
       FIG. 14  illustrates a TX wireless device  1402 . 1  with three RX wireless devices  1403  linked to the TX wireless device  1402 . 1  in accordance with some embodiments. RX wireless devices  1403  may be wireless devices  202  that are receiving transmission from TX wireless device  1402 . 5 . TX wireless device  1402 . 1  may be a wireless device  202  linked to RX wireless devices  1403 . The links  1404 . 1 ,  1404 . 2 , and  1404 . 3  may be links  204  as described in conjunction with  FIGS. 2 and 3 . TX  1402 . 2  may be a wireless device  202  that will spatially reuse at least some of the bandwidth used by TX wireless device  1402 . 1  and RX wireless devices  1403 . 4 . 
     In some embodiments TX wireless device  1402 . 1  may signal one margin  507 ,  900 ,  1000 ,  1100 ,  1202 , and  1302  for multiple links  1404  such as links  1404 . 1 ,  1404 . 2 , and  1404 . 3 . The wireless device  202  such as TX wireless device  1402 . 1  may signal the minimum margin  507 ,  900 ,  1000 ,  1100 ,  1202 , and  1302  among all the RX wireless devices  1403  linked  1404  to the TX wireless device  1402 . 
     For example, if M J  is the margin  507 ,  900 ,  1000 ,  1100 ,  1202 ,  1302  for link  1404  J, then the wireless device  202  may determine the M J  for each link  1404  J to the TX wireless device  1402 . 1 , and select the J with the minimum margin  507 ,  900 ,  1000 ,  1100 ,  1202 ,  1302  and transmit A as the margin  507 ,  900 ,  1000 ,  1100 ,  1202 ,  1302 . 
     For margin  900 , the TX wireless device  1402 . 1  may determine tolerated interference levels of all links (TI)=minimum (M J +I J ), where J is considered for all the links  1404  from 1 to the number of links  1404 , A is the margin for link J, and I J  may be the interference of link J. In  FIG. 12 , M is M  1202  and I is average interference level  1206 . The TX wireless device  1402 . 1  would then set additional interference  902  to A (M  1202 ) and current interference level  904  to I J  (average interference level  1206 .) 
     For margin  1000 , the TX wireless device  1402 . 1  will set tolerable interference level  1002  to the minimum of M J  where M J  is M  1302 . For margin  1100 , the TX wireless device  1402 . 1  will set tolerable interference level  1002  to the minimum of A where A is M  1302  plus the TX power of TX wireless device  1402 . 1 . 
     The method  400  may continue at operation  406  with spatially reuse a sub-channel. Operation  406  is described in conjunction with  FIG. 15 .  FIG. 15  illustrates a method of spatial reuse in accordance with some embodiments. 
     Illustrated in  FIG. 15  is time  1502  along a horizontal axis and the transmitter along the vertical axis. The transmitter TX  1402 . 1  transmits on a sub-channel a first portion of the packet  1504  which may include a spatial reuse indication  506 . In some embodiments the spatial reuse indication  506  may have been transmitted in a previous packet as described in conjunction with  FIGS. 6 and 7 . TX  1402 . 1  may transmit data  1506  which may be a packet such as data or another type of packet. 
     TX  1402 . 2  may receive the preamble  1504  and may identify a spatial reuse opportunity  1510  based on the preamble  1404 , or as described in conjunction with  FIGS. 6 and 7  from a previous packet. The TX 2   1402 . 2  may not be able to identify the spatial reuse opportunity  506  until time  1509 . At time  1509  the TX  1402 . 2  may have received the preamble  1504  and determined that a spatial reuse opportunity  1510  exits. The spatial reuse opportunity  506  may be a duration that is based on the time to transmit packet  1506  and may be the same sub-channel or a portion of the sub-channel in use by TX  1402 . 1 . 
     TX  1402 . 2  may then backoff  1512  in accordance with IEEE 802.11 communications protocol. In some embodiments, TX  1402 . 2  may adjust the size of the backoff  1112  or may not backoff  1112 . TX 2   802 . 2  may adjust the transmission power or CCA parameters, which may be based on information in the spatial reuse indication  506  such as margin  507 ,  900 ,  1000 ,  1100 . For example, for a margin  1000  ( FIG. 10 ), TX  1402 . 2  may set the transmission power to interference  206 . 7  ( FIG. 2 )+the current transmission power−tolerable interference  1002 −TX power  1004 . As another example, for a margin  1100  ( FIG. 11 ), TX  1402 . 2  may set the transmission power to the transmission power to interference  206 . 7 +the current transmission power−tolerable interference level+TX power  1102 . 
     TX  1402 . 2  may then transmit data  1515  during the spatial reuse  1514 . Data  1515  may be a packet. Spatial reuse  1514  may extend past spatial reuse opportunity  1510  in accordance with some embodiments. Data  1515  may end before the end of the spatial reuse opportunity  1510 . TX  1402 . 2  may only utilize the spatial reuse opportunity  1510  links  1404  are D2D links. 
     TX  1402 . 2  may ignore a medium busy condition if it uses another mechanism to determine if there are additional gains and TX  1402 . 2  does not affect existing transmissions. TX  1402 . 2  may adjust the window size for backoff  1412  prior to performing a backoff  1412 . The window size may be based on the spatial reuse indication  506 . The window size may be only for the spatial reuse opportunity  1510  and TX  1402 . 2  may revert to the previous window size after the spatial reuse opportunity  1510 . In some embodiments, TX  1402 . 2  may not reset the window size after the data  1515  transmission to insure that other devices have a fair opportunity to use the sub-channel or wireless medium. 
     In some embodiments, a receiver of data  1515  may perform adjustments to CCA and/or the power transmission level for the spatial reuse opportunity  1510  based on control frames received from TX  1402 . 2 . In some embodiments, a receiver of the data  1515  may ignore the network allocation vector (NAV) and respond to control frames from TX  1402 . 2  such as a CTS for spatial reuse. 
       FIG. 16  illustrates a method  1600  for uplink spatial reuse in accordance with some embodiments.  FIG. 16  will be described in conjunction with  FIGS. 17 and 18 . Method  1600  may be for spatial reuse of a bandwidth during an uplink OFDMA/MU-MIMO period or transmission opportunity that may be initiated by a trigger frame  1805  for D2D links. For example, the UL transmissions  1815  may present a spatial reuse opportunity  1810 . 
     The method begins at operation  1602  with identify multiple user D2D links. D2D links are identified so that another link can potentially spatially reuse the same or an overlapping sub-channel or channel. The D2D links may be identified as described in conjunction with  FIG. 4 . In some embodiments, the receiver may identify the D2D opportunities rather than the transmitter which may save the feedback signaling form the receiver.  FIG. 17  illustrates an example where a receiver may identify the D2D links in accordance with some embodiments. RX wireless device  1702 . 4  and TX wireless devices  1702 . 1 ,  1702 . 2 , and  1702 . 3  may be wireless devices  202 . TX  1702 . 4  may be a master station  102  that may have transmitted trigger frame  1805  to the TX wireless devices  1702 . 1 ,  1702 . 2 , and  1702 . 3 , and the TX wireless devices  1702 . 1 ,  1702 . 2 ,  1702 . 3  may be transmitting UL transmissions  1815  to the master station  102 . The links  1704 . 1 ,  1704 . 2 ,  1704 . 3  may be D2D links. The RX wireless device  1702 . 4  may determine that the links  1704 . 1 ,  1704 . 2 ,  1704 . 3  are D2D links based on received signals such as previous UL transmissions  1815  or other transmissions such as association transmissions from the TX wireless devices  1702 . 1 ,  1702 . 2 ,  1702 . 3 . 
     The method  1600  may continue at operation  1604  with signal a spatial reuse indication  506  in accordance with some embodiments. The wireless device  202  may signal the spatial reuse indication  506  as described in conjunction with  FIG. 4 . In some embodiments the wireless device  202  such as RX wireless device  1702 . 4  may signal the spatial reuse indication in a trigger frame  1805 . For example, the trigger frame  1805  may comprise PHY/MAC signaling for the spatial reuse indication  506 . The trigger frame  1805  may use a MAC portion if a legacy preamble is used. The trigger frame  1805  may signal a MCS selection and transmission power for uplink stations, so that the master station  102  may be able to choose the right margin for spatial reuse signaling. 
     The method  1600  may continue at operation  1606  with spatially reuse a sub-channel. Operation  1606  is described in conjunction with  FIGS. 17 and 18 . 
       FIG. 18  illustrates a method  1800  for uplink spatial reuse in accordance with some embodiments. TX wireless device  1804 . 2 , TX wireless device  1804 . 3 , and TX wireless device  1804 . 1  may be wireless devices  202 . TX wireless device  1804 . 1  may be RX wireless device  1702 . 4  ( FIG. 17 ). TX wireless device  1804 . 2  is not illustrated in  FIG. 17 . TX wireless device  1804 . 3  may be TX wireless devices  1702 . 1 ,  1702 . 2 ,  1702 . 3 . The trigger frame  1805  may be a trigger frame  1805  that indicates resources for the TX wireless devices  1804 . 3  to use to transmit in the uplink to the TX wireless device  1804 . 1 . The UL transmissions  1815  may be the TX wireless devices  1804 . 3  transmitting data to the TX wireless device  1804 . 1  in response to the trigger frame  1805 . The data  1817  may TX wireless device  1804 . 2  transmitting data  1817  in a spatial reuse  1814  in a spatial reuse opportunity  1810 . Backoff  1812  may be a time period where TX wireless device  1804 . 2  contends for the wireless medium. 
     TX wireless device  1804 . 2  may determine that a spatial reuse opportunity  1810  exists based on the trigger frame  1805 . For example, at time  1809  the TX wireless device  1804 . 2  may have received the spatial reuse indication  506  from a HE PHY header. The TX wireless device  1804 . 2  may have to receive the entire trigger frame  1805  to receive the spatial reuse indication  506  in a MAC portion of the trigger frame  1805 . 
     The trigger frame  1805  as part of the resource allocation includes a duration for the transmission opportunity. The TX wireless device  1804 . 2  may then determine the duration of the spatial reuse opportunity  1810  from the trigger frame  1805 . The TX wireless device  1804 . 2  may also determine the start time of the spatial reuse opportunity  1810  from the trigger frame  105 . 
     The TX wireless device  1804 . 2  may transmit data  1817  during the spatial reuse opportunity  1810 . In some embodiments the TX wireless device  1804 . 2  may extend the time to transmit data  1817  past the spatial reuse opportunity  1810 . In some embodiments the TX wireless device  1804 . 2  may not backoff  1812  and may transmit data  1817  at the start of the spatial reuse opportunity  1810 . In some embodiments the TX wireless device  1804 . 2  may measure the interference  1818  and determine whether to transmit or not based on the interference. 
     In some embodiments spatial reuse opportunity  1810  may be for a MU-MIMO uplink. In some embodiments spatial reuse opportunity  1810  may be for a MU-MIMO downlink. In some embodiments spatial reuse opportunity  1810  may be for an OFDMA downlink. 
       FIG. 19  illustrates two links  1906  in accordance with some embodiments. TX 1   1902 . 1 , TX 2   1902 . 2 , RX 1   1904 . 1 , and RX 2   1904 . 2  may be wireless devices  202 . Link 1   1906 . 1  and link 2   1906 . 2  may be links  206  between TX 1   1902 . 1 , TX 2   1902 . 2 , and RX 1   1904 . 1 , RX 2   1904 . 2 , respectively. Link 1   1906 . 1  and link 2   1906 . 2  may be D2D links.  FIGS. 12 and 13  illustrate margins  1202 ,  1302  in accordance with some embodiments. 
       FIG. 20  illustrates the two links  1906  illustrated in  FIG. 19  with signal strengths in accordance with some embodiments. S 11  is the signal strength from TX 1   1902 . 1  to TX 2   1902 . 2 . S 12  is the signal strength from TX 1   1902 . 1  to RX 2   1904 . 2 . S 21  is the signal strength from TX 2   1902 . 2  to TX 1   1902 . 1 . S 22  is the signal strength from TX 2   1902 . 2  to RX 1   1904 . 1 . As described in conjunction with  FIG. 17  TX 1   1902 . 1  may determine the link 1   1906 . 1   
     When TX 2   1902 . 2  receives the preamble  1504  or trigger frame  1805  from TX 1   1902 . 1 , the signal strength is S 11 . If the power difference between TX 1   1902 . 1  and TX 2   1902 . 2  is D=P 1 −P 2 , then the signal strength S 21  is S 11 -D, where P 1  is the transmission power of TX 1   1902 . 1  and P 2  is the transmission power of TX 2   1902 . 2 . In some embodiments, since link 1   1906 . 1  is a D2D link, TX 2   1902 . 2  may assume that TX 1   1902 . 1  and RX 1   1904 . 1  are close. RX 1   804 . 1  may then assume that signal values S 21  and S 22  have values that are close to one another. TX 2   1902 . 2  can then infer its signal strength S 21  or interference to RX 1   1904 . 1  based on the received signal strength S 11 . In some embodiments, TX 2   1902 . 2  may approximate signal strength S 22  as equal to signal strength S 11  if link 2   1906 . 2  is a D2D link. 
     TX 2   1902 . 2  may adjust its power transmission for the spatial reuse  1514 ,  1814  in some embodiments as follows. TX 2   1902 . 2  receives M  507  in the spatial reuse indication  506 . TX 2   1902 . 2  may estimate signal strength S 21  as S 11 -D, where D is the power difference between TX 1   1902 . 1  and TX 2   1902 . 2 . TX 2   1902 . 2  may estimate the additional interference above M of RX 1   1904 . 1  as A=S 21 −M=S 11 −D−M=S 11 −(P 1 −P 2 )−M. TX 2   1902 . 2  may reduce power to some value larger than A+K, if A+K&gt;0, where K can be a constant. TX 2   1902 . 2  may select a MCS based on the final transmission power and the average interference reported by RX 2   1904 . 2 . TX 2   1902 . 2  may reduce the transmission power only for the spatial reuse  1514 ,  1814 . 
     TX 2   1902 . 2  may adjust its power transmission for the spatial reuse  1514 ,  1814  in some embodiments as follows. TX 2   1902 . 2  may use a known threshold L for HEW stations  104  or wireless device  202 . L may be determined by a communication protocol and may be predefined. TX 2   1902 . 2  may receive M  507  in the spatial reuse indication  1514 ,  1814 . M  507  may be equal to tolerable interference-(L−P 1 ) rather than M being equal to tolerable interference. TX 2   1902 . 2  may estimate S 21 =S 11 −(L−P 2 ) rather than S 21 =S 11 −D. TX 2   1902 . 2  may estimate the additional interference above the tolerable interference of RX 1   1904 . 1  as A=S 21 −M=S 11 −(L−P 2 )−tolerable interference+(L−P 1 )=S 11 −(P 1 −P 2 )−tolerable interference. TX 2   1902 . 2  may reduce power to some value larger than A+K, if A+K&gt;0, where K can be a constant. TX 2   1902 . 2  may select a MCS based on the final transmission power and the average interference reported by RX 2   1904 . 2 . TX 2   1902 . 2  may reduce the transmission power only for the spatial reuse  1514 ,  1814 . 
     In some embodiments, TX 2   1902 . 2  may adjust the CCA as follows. TX 2   1902 . 2  may determine the additional interference that RX 1   1904 . 1  can tolerate by using M  507  transmitted by TX 1   1902 . 1  and based on link 1   1906 . 1  being a D2D link. TX 2   1902 . 2  may only use the spatial reuse opportunity  1514 ,  1814  if link 2   1906 . 2  is also a D2D link. TX 2   1902 . 2  may increase CCA by M-D, where D is the transmission power difference between TX 1   1902 . 1  and TX 2   1902 . 2 . TX 2   1902 . 2  may select a MCS based on the final transmission power and the average interference reported by RX 2   1904 . 2 . In some embodiments, TX 2   1902 . 2  may increase CCA only for the spatial reuse  1514 ,  1814 . 
       FIG. 21  illustrates a HEW device in accordance with some embodiments. HEW device  2100  may be an HEW compliant device that may be arranged to communicate with one or more other HEW devices, such as HEW STAs  104  ( FIG. 1 ) or master station  102  ( FIG. 1 ) as well as communicate with legacy devices  106  ( FIG. 1 ). HEW STAs  104  and legacy devices  106  may also be referred to as HEW devices and legacy STAs, respectively. HEW device  2100  may be suitable for operating as master station  102  ( FIG. 1 ) or a HEW STA  104  ( FIG. 1 ). In accordance with embodiments, HEW device  2100  may include, among other things, a transmit/receive element  2101  (for example an antenna), a transceiver  2102 , physical (PHY) circuitry  2104 , and media access control (MAC) circuitry  2106 . PHY circuitry  2104  and MAC circuitry  2106  may be HEW compliant layers and may also be compliant with one or more legacy IEEE 802.11 standards. MAC circuitry  2106  may be arranged to configure packets such as a physical layer convergence procedure (PLCP) protocol data unit (PPDUs) and arranged to transmit and receive PPDUs, among other things. HEW device  2100  may also include circuitry  2108  and memory  2110  configured to perform the various operations described herein. The circuitry  2108  may be coupled to the transceiver  2102 , which may be coupled to the transmit/receive element  2101 . While  FIG. 21  depicts the circuitry  2108  and the transceiver  2102  as separate components, the circuitry  2108  and the transceiver  2102  may be integrated together in an electronic package or chip. 
     In some embodiments, the MAC circuitry  2106  may be arranged to contend for a wireless medium during a contention period to receive control of the medium for the HEW control period and configure an HEW PPDU. In some embodiments, the MAC circuitry  2106  may be arranged to contend for the wireless medium based on channel contention settings, a transmitting power level, and a CCA level. 
     The PHY circuitry  2104  may be arranged to transmit the HEW PPDU. The PHY circuitry  2104  may include circuitry for modulation/demodulation, upconversion/downconversion, filtering, amplification, etc. In some embodiments, the circuitry  2108  may include one or more processors. The circuitry  2108  may be configured to perform functions based on instructions being stored in a RAM or ROM, or based on special purpose circuitry. The circuitry  2108  may be termed processing circuitry in accordance with some embodiments. The circuitry  2108  may include a processor such as a general purpose processor or special purpose processor. The circuitry  2108  may implement one or more functions associated with transmit/receive elements  2101 , the transceiver  2102 , the PHY circuitry  2104 , the MAC circuitry  2106 , and/or the memory  2110 . 
     In some embodiments, the circuitry  2108  may be configured to perform one or more of the functions and/or methods described herein and/or in conjunction with  FIGS. 1-21  such as, for example, such as generating, transmitting, receiving, and operating in accordance with signaling for a spatial reuse. Additionally, the master station  102  and/or HEW device  104  may be configured to encode additional format or configuration information in the MCS field and/or using tail bits. 
     In some embodiments, the transmit/receive elements  1201  may be two or more antennas that may be coupled to the PHY circuitry  1204  and arranged for sending and receiving signals including transmission of the HEW packets. The transceiver  1202  may transmit and receive data such as HEW PPDU and packets that include an indication that the HEW device  1200  should adapt the channel contention settings according to settings included in the packet. The memory  1210  may store information for configuring the other circuitry to perform operations for configuring and transmitting HEW packets and performing the various operations to perform one or more of the functions and/or methods described herein and/or in conjunction with  FIGS. 1-21  such as, for example, such as generating, transmitting, receiving, and operating in accordance with signaling for a spatial reuse. Additionally, the master station  102  and/or HEW device  104  may be configured to encode additional format or configuration information in the MCS field and/or using tail bits. 
     In some embodiments, the HEW device  2100  may be configured to communicate using OFDM communication signals over a multicarrier communication channel. In some embodiments, HEW device  2100  may be configured to communicate in accordance with one or more specific communication standards, such as the Institute of Electrical and Electronics Engineers (IEEE) standards including IEEE 802.11-2012, 802.11n-2009, 802.11ac-2013, 802.11ax, or anther standard such as one or more of the standards disclosed in conjunction with  FIG. 1 . DensiFi, standards and/or proposed specifications for WLANs, or other standards as described in conjunction with  FIG. 1 , although the scope of the invention is not limited in this respect as they may also be suitable to transmit and/or receive communications in accordance with other techniques and standards. In some embodiments, the HEW device  2100  may use 4× symbol duration of 802.11n or 802.11ac. 
     In some embodiments, an HEW device  2100  may be part of a portable wireless communication device, such as a personal digital assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a smartphone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), an access point, a base station, a transmit/receive device for a wireless standard such as 802.11 or 802.16, or other device that may receive and/or transmit information wirelessly. In some embodiments, the mobile device may include one or more of a keyboard, a display, a non-volatile memory port, multiple antennas, a graphics processor, an application processor, speakers, and other mobile device elements. The display may be an LCD screen including a touch screen. 
     The transmit/receive element  2101  may comprise one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (MIMO) embodiments, the antennas may be effectively separated to take advantage of spatial diversity and the different channel characteristics that may result. 
     Although the HEW device  2100  is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs), and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements may refer to one or more processes operating on one or more processing elements. 
     The following examples pertain to further embodiments. Example 1 is an apparatus of a high-efficiency (HE) wireless local area network (HEW) station, including circuitry configured to: determine if a plurality of links with a plurality of wireless stations are device-to-device links that indicate that there is a spatial reuse opportunity; and transmit a packet that comprises a spatial reuse indication that there is the spatial reuse opportunity, if the spatial reuse opportunity is indicated. 
     In Example 2, the subject matter of Example 1 can optionally include where the packet is one from the following group: a management frame, a data frame, and a trigger frame. 
     In Example 3, the subject matter of Examples 1 or 2 can optionally include where the spatial reuse opportunity is at least one from the following group: an uplink orthogonal frequency division multiple access (OFDMA) with the plurality of wireless stations, a downlink OFDMA with the plurality of wireless stations, and a downlink multiple users multiple-input multiple-output (MU-MIMO). 
     In Example 4, the subject matter of any of Examples 1-3 can optionally include where the circuitry is further configured to: transmit a trigger frame to the plurality of wireless stations; in response to the trigger frame, receive data from each of the plurality of wireless stations in accordance with uplink orthogonal frequency division multiple access (OFDMA); and determine the plurality of links with the plurality of wireless stations are the D2D links that indicate the spatial reuse opportunity based on the signals transmitted in response to the trigger frame from the plurality of wireless stations. 
     In Example 5, the subject matter of any of Examples 1-4 can optionally include where the spatial reuse indication includes a margin that indicates at least one of the following group: an additional interference that can be tolerated by the HEW station, current interference level, and a transmit power of the HEW station; a tolerable interference level and the transmit power of the HEW station; and, a tolerable interference level plus the transmit power of the HEW station. 
     In Example 6, the subject matter of any of Examples 1-5 can optionally include where the circuitry is further configured to: determine a link with a lowest margin of the plurality of links, and wherein the spatial reuse indication includes the lowest margin. 
     In Example 7, the subject matter of Example 6 can optionally include where the lowest margin indicates at least one of the following group: an additional interference that can be tolerated by a corresponding wireless station of the link, a current interference level of the link, and a transmit power of the corresponding wireless station of the plurality of wireless stations; a tolerable interference level and the transmit power of the corresponding wireless station of the plurality of wireless stations; and, a tolerable interference level plus the transmit power of the corresponding wireless station of the plurality of wireless stations. 
     In Example 8, the subject matter of any of Examples 1-7 can optionally include where the spatial reuse indication includes a margin that indicates at least one of the following group: additional interference, current interference level, transmit power, and tolerable interference level. 
     In Example 9, the subject matter of any of Examples 1-9 can optionally include where the HEW station is a master station, and wherein the signals are received in response to a trigger frame transmitted by the HEW station. 
     In Example 10, the subject matter of any of Examples 1-9 can optionally include where the circuitry is further configured to: receive an indication from one or more of the plurality of wireless stations that the corresponding link of the plurality of links is a device-to-device link; and determine the plurality of links with the plurality of wireless stations are device-to-device links based on the indication from the one or more of the plurality of wireless stations. 
     In Example 11, the subject matter of any of Examples 1-10 can optionally include where the circuitry is further configured to transmit in accordance with at least one from the following group: orthogonal frequency division multiple access (OFDMA) and multiple-user multiple input and output (MU-MIMO). 
     In Example 12, the subject matter of any of Examples 1-11 can optionally include where the spatial reuse indication is to be transmitted in at least one from the following group: a HE signal (SIG) preamble and media access control (MAC) of the packet. 
     In Example 13, the subject matter of any of Examples 1-12 can optionally include where the plurality of wireless stations are each one from the following group: a legacy device, a second HEW station, and a master station. 
     In Example 14, the subject matter of any of Examples 1-13 can optionally include where the circuitry further includes processing circuitry and transceiver circuitry. 
     In Example 15, the subject matter of Example 14 can optionally include memory and a transceiver coupled to the circuitry; and, one or more antennas coupled to the transceiver. 
     Example 16 is a method performed by a high-efficiency (HE) wireless local area network (WLAN) (HEW) device. The method including determining if a plurality of links with a plurality of wireless stations are device-to-device links that indicate that there is a spatial reuse opportunity; and transmitting a packet that comprises a spatial reuse indication that there is the spatial reuse opportunity, if the spatial reuse opportunity is indicated. 
     In Example 17, the subject matter of Example 16 can optionally include where the spatial reuse opportunity is at least one from the following group: an uplink orthogonal frequency division multiple access (OFDMA) with the plurality of wireless stations, a downlink OFDMA with the plurality of wireless stations, and a downlink multiple users multiple-input multiple-output (MU-MIMO). 
     In Example 18, the subject matter of Examples 16 and 17 can optionally include where the method further comprises: transmitting a trigger frame to the plurality of wireless stations; receiving data from each of the plurality of wireless stations in accordance with uplink orthogonal frequency division multiple access (OFDMA) in response to the trigger frame; and determining the plurality of links with the plurality of wireless stations are the D2D links that indicate the spatial reuse opportunity based on the signals transmitted in response to the trigger frame from the plurality of wireless stations. 
     In Example 19, the subject matter of any of Examples 16-18 can optionally include where the spatial reuse indication includes a margin that indicates at least one of the following group: an additional interference that can be tolerated by the HEW station, current interference level, and a transmit power of the HEW station; a tolerable interference level and the transmit power of the HEW station; and, a tolerable interference level plus the transmit power of the HEW station. 
     Example 20 is an apparatus of a high-efficiency (HE) wireless local area network (HEW) station. The apparatus including circuitry configured to: receive a packet from a second HEW station, wherein the packet includes an indication that there is a spatial opportunity; adjust at least one of the following group: a transmit power and a clear channel assessment; and transmit one or more packets to each of a plurality of wireless devices within the spatial opportunity in accordance with device-to-device communication in accordance with orthogonal frequency division multiple access (OFDMA). 
     In Example 21, the subject matter of Example 20 can optionally include where the indication includes an indication of how much additional interference can be tolerated within the spatial opportunity, and wherein the circuitry is further configured to reduce the transmit power of the HEW STA based on the indication of how much additional interference can be tolerated within the spatial opportunity. 
     In Example 22, the subject matter of Examples 20 and 21 can optionally include where the indication includes an indication of how much additional interference can be tolerated within the spatial opportunity, and where the circuitry is further configured to increase a signal detect level of the clear channel assessment based on the indication of how much additional interference can tolerate within the spatial opportunity, and where the circuitry is further configured to perform a mid-packet detect to determine if a wireless medium is busy. 
     In Example 23, the subject matter of any of Examples 20-22 can optionally include memory and a transceiver coupled to the circuitry; and one or more antennas coupled to the transceiver. 
     Example 24 is a non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of a high-efficiency (HE) wireless local-area network (WLAN) (HEW) master station, the operations to configure the one or more processors to cause the HEW master station to: determine if a plurality of links with a plurality of wireless stations are device-to-device links that indicate that there is a spatial reuse opportunity; and transmit a packet that comprises a spatial reuse indication that there is the spatial reuse opportunity, if the spatial reuse opportunity is indicated. 
     In Example 25, the subject matter of Example 24 can optionally include where the one or more processors are further configured to cause the HEW master station to: determine a link with a lowest margin of the plurality of links, and wherein the spatial reuse indication includes the lowest margin, and wherein the lowest margin indicates at least one of the following group: an additional interference that can be tolerated by a corresponding wireless station of the link, a current interference level of the link, and a transmit power of the corresponding wireless station of the plurality of wireless stations; a tolerable interference level and the transmit power of the corresponding wireless station of the plurality of wireless stations; and, a tolerable interference level plus the transmit power of the corresponding wireless station of the plurality of wireless stations. 
     The Abstract is provided to comply with 37 C.F.R. Section 1.72(b) requiring an abstract that will allow the reader to ascertain the nature and gist of the technical disclosure. It is submitted with the understanding that it will not be used to limit or interpret the scope or meaning of the claims. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.