First of all thanks for your suggestion,
I am using gnuradio 3.7 & started installation of ieee 802.11 from
https://github.com/bastibl/gr-ieee802-11 During installation of log4cpp & IT++ for sudo port install log4cpp I was getting sudo:port:command not found. After successful installation of gr_ieee802.11, when I was running example ofdm_loopback.grc, it is not showing entire blocks & giving error
<<< Welcome to GNU Radio Companion 3.7.1-52 >>>
Loading: "/home/naveen/gr-ieee802-11/examples/ofdm_loopback.grc"
>>> Error: Block key "blocks_ctrlport_monitor_performance" not found in Platform - grc(GNU Radio Companion)
>>> Error: Block key "ieee802_11_ofdm_parse_mac" not found in Platform - grc(GNU Radio Companion)
>>> Error: Block key "ofdm_phy_hier" not found in Platform - grc(GNU Radio Companion)
>>> Error: Block key "ieee802_11_ofdm_mac" not found in Platform - grc(GNU Radio Companion)
>>> Error: Block key "foo_packet_pad" not found in Platform - grc(GNU Radio Companion)
>>> Error: Block key "foo_wireshark_connector" not found in Platform - grc(GNU Radio Companion)
>>> Error: Connection between foo_wireshark_connector_0(0) and blocks_file_sink_0(0) could not be made.
source block id "foo_wireshark_connector_0" not in block ids
>>> Error: Connection between foo_packet_pad_0(0) and blocks_multiply_xx_0(0) could not be made.
source block id "foo_packet_pad_0" not in block ids
>>> Error: Connection between ofdm_phy_hier_1(0) and foo_packet_pad_0(0) could not be made.
source block id "ofdm_phy_hier_1" not in block ids
>>> Error: Connection between blocks_add_xx_0(0) and ofdm_phy_hier_1(0) could not be made.
sink block id "ofdm_phy_hier_1" not in block ids
>>> Error: Connection between ofdm_phy_hier_1(mac_out) and ieee802_11_ofdm_parse_mac_0(in) could not be made.
source block id "ofdm_phy_hier_1" not in block ids
>>> Error: Connection between blocks_message_strobe_0(strobe) and ieee802_11_ofdm_mac_0(app in) could not be made.
sink block id "ieee802_11_ofdm_mac_0" not in block ids
>>> Error: Connection between ofdm_phy_hier_1(mac_out) and ieee802_11_ofdm_mac_0(phy in) could not be made.
source block id "ofdm_phy_hier_1" not in block ids
>>> Error: Connection between ieee802_11_ofdm_mac_0(phy out) and ofdm_phy_hier_1(mac_in) could not be made.
source block id "ieee802_11_ofdm_mac_0" not in block ids
>>> Error: Connection between ieee802_11_ofdm_mac_0(phy out) and foo_wireshark_connector_0(in) could not be made.
source block id "ieee802_11_ofdm_mac_0" not in block ids
>>> Done
Showing: "/home/naveen/gr-ieee802-11/examples/ofdm_loopback.grc"