Ieee wireless standards pdf

Approved PAR. Working Group Christy Bahn. IEEE P This amendment defines modifications to both the IEEE It enables absolute and relative position estimation with higher-accuracy executing on the same PHY-type. Further, it reduces existing wireless medium utilization and power consumption, is scalable to dense deployments, and includes security features.

It also incorporates Amendments 1 through 8 including a corrigendum. This amendment specifies enhancements to the IEEE It enables higher layer functionalities to provide overall end-to-end solutions. The main goals of this amendment are aiding network discovery and selection, enabling information transfer from external networks, enabling emergency services, and interfacing subscription service provider networks SSPNs to IEEE This amendment defines enhancements to the IEEE This amendment provides direct-link setup enhancements to the IEEE The direct-link setup is made independent of the AP by tunneling the protocol messages inside data frames.

This amendment describes protocols for IEEE The purpose of this amendment is to improve the IEEE It also incorporates Amendments 1 to 10 published in to A mechanism for prioritization of management frames is provided and a protocol to communicate management frame prioritization policy is specified in this amendment.

Enhancements to the IEEE Independent operating mode. Figure 2 Infrastructure Mode However, in the independent mode or ad hoc mode, the STAs can directly communicate with each other. Two new MAC techniques were introduced in They are known as Traffic Classes TC. It is quite similar to DCF. Block Acknowledgement The block acknowledgement mechanism was also introduced in But ACKs caused high overhead and waiting time delay.

To overcome this, IEEE Even though it speeds up the process but the primary disadvantage of retransmitting the entire block again on failure to receive an ACK signal still persists. So the amount of bandwidth consumed is twice the actual rate of transmission. DLP is a technique which allows two STAs to directly communicate with each other without using an Access Point, avoiding excess of bandwidth.

This eliminates the timing problem in PCF. Now if a QAP can handle the transmission subject to all the QoS parameters passed to it, it accepts it otherwise it rejects the request, which can again be retried with a relatively lower QoS parameter. In [12] it was proposed that the polling mechanism could be replaced with a request based scheduler. One of the well known contention based protocol of the IEEE The protocol allows multiple users to use the same radio frequency spectrum by establishing rules in which a transmitter provides reasonable opportunities to other transmitters when both of them simultaneously try to access the same channel.

It consists of separate procedures for initiating new transmissions, determining the state of the channel and for managing retransmissions in the event of a busy channel. This will provide an opportunity to the WLAN to choose a channel which is less noisy and the least likely to cause any interference.

In addition, ECSA also provides other functionalities besides dynamic channel selection like for instance, the licensed operator can send ECSA commands to any stations operating under their control, either registered or unregistered [39].

However, IEEE But after IEEE In addition, the DSE provides benefits like enabling a dependent STA to connect to its nearest AP for a short period of time and use the internet to complete the channel permission process with the enabling station. This facility reduces the likelihood of a dependent STA to cause interference while attempting to connect to a far off enabling station. The personal privacy and security of end users are ensured while, at the same time, licensees will have the information necessary to resolve disputes.

This is achieved as the devices based on IEEE The enabling stations also transmit their unique identifier indicating their location. The FCC database will also contain the location of the enabling station that will identify the licensee.

The dependent STAs provide the location of the station that enabled it plus a unique string supplied by the enabling station. This ensures that to resolve disputes the responsible party, the licensee, can be contacted.

This method alleviates the problems associated with having the dependent STA broadcasting its location. However this method would increase the cost and complexity of devices. The mobile user profiles were originally not defined in the IEEE However, the cellular IP Architecture provides a solution for seamless transition between different LAN networks [24].

Here, several WLANs are connected to the internet and are interconnected among them using a gateway, which keeps records of all the moving paths. A bridge is simpler and efficient than an IP router. In , the It adds a sub clause under 2. As of now, this standard is a part of IEEE Issues related to regulatory differences in various countries are covered and also defined operation parameters at the 5MHz frequency band, but that only for North America, Europe and Japan.

This support also included the addition of a country information element to beacons, probe requests as well as to probe responses. This country information element greatly simplified creation of As discussed earlier, IEEE In addition, IEEE These enhancements should provide the quality which is necessary for services such as IP telephony and video streaming [ 14].

In addition to providing communication among WLAN stations in its area, an AP can also function as a bridge that connects any two Thus, IEEE So to handle such situations, IEEE These were: 1. On the hand, TPC is used to keep the signal level below a certain preset level if there is a satellite signal in the nearby channels. Moreover, TPC can also be used to improve the link condition by switching over the working frequency to a more suitable channel which is clearer and also reduce power consumption [19].

The security and authentication mechanisms at the MAC layer were defined in this standard. The Wi-Fi Alliance refers to their interoperable implementation of the full The They are: 1.

The 4-Way Handshake 2. The Group Key Handshake. These utilize the authentication services and port access control described in the IEEE The RSN is a security network that only allows for the creation of robust security network associations RSNAs , a type of association used by a pair of STAs if the procedure to establish authentication or association between them includes the 4-Way Handshake.

It provided Wireless LAN operation in the 4. The standard enabled the management of the air interface between several APs, including the following: 1. To improve roaming decisions, an AP can provide a site report to a mobile device when the AP determines that the mobile device is going away from it.

The site report lists APs from best to worst that a mobile device can use in changing over to another AP [24]. Each mobile device provides a noise histogram that displays all non The access point collects the statistics on how long a channel is in active use during a given time. This data enable the AP to regulate access to a given channel. APs can query mobile devices to collect statistics, such as retries, packets transmitted, and packets received.

This gives the AP a more complete view of the network performance. Moreover, no task group was named IEEE The revisions as well as clarifications and modifications are produced periodically. First conceived in the year , the IEEE These enhancements include items such as changes to signal encoding schemes, multiple antennas, smart antennas, and changes to MAC protocols [].

The standard uses MIMO [26] and various new modulation and coding mechanisms to increase the data rates. The standard uses a fixed channel bandwidth of 20MHz, which is useful for backward compatibility with older standards. Data rates up to Mbps are achieved only with the maximum of four spatial streams using one 40 MHz-wide channel [25].

Frame Aggregation 2. There is severe under utilization when the MAC frames are small. The frame aggregation technique enabled STAs to aggregate small frames into larger ones.

To maximize efficiency, the maximum frame size is increased thereby allowing longer frames [27]. It defines enhancements to It includes data exchange between high-speed passenger vehicles and ambulances and the roadside infrastructure in the licensed ITS band of 5. In this protocol, the vehicles send information about their traffic parameters like speed, distance from other vehicles etc.

In this way each vehicle in the corresponding neighbourhood knows about the traffic status and acts accordingly. This standard provided fast roaming, even for vehicles in motion. It reduced the roaming delay between two basic service sets BSS to less than 50 ms. The standard also refined the mobile client transition process between APs by redefining the security key negotiation protocol, which permit negotiations and requests for wireless resources.

It defines how wireless devices can interconnect to create a WLAN mesh network, which may be used for static topologies as well as for ad-hoc networks [36]. Initially in , the It became a Task Group in In the following year i. After a series of eliminations and mergers, the proposals dwindled to two the "SEE-Mesh" and "Wi-Mesh" proposals , which became a joint proposal in fig.

Network device which is based on the IEEE Mesh STAs form mesh links with each other, over which mesh paths can be established using a routing protocol fig.

But it still allows vendors to operate using alternate protocols. They can also collocate with Also, mesh STAs can collocate with an In both the cases, There are no defined roles in a mesh — no clients and servers, no initiators and also no responders.

Security protocols used in a mesh must, therefore, be true peer- to-peer protocols where either side can initiate to the other or both sides can initiate simultaneously.

A key establishment protocol called "Simultaneous Authentication of Equals" SAE defines a secure password-based authentication technique. SAE is based on Diffie—Hellman key exchange using finite cyclic groups which can be a primary cyclic group or an elliptic curve.

The problem on using Diffie—Hellman key exchange is that it does not have an authentication mechanism. Hence to solve the authentication problem, the resulting key is influenced by a pre-shared key as well as the MAC addresses of both peers [34]. SAE exchange takes place only when both the peers discover each other. On successful completion of SAE, each peer knows that the other party possesses the mesh password and, as a by-product of SAE exchange, the two peers establish a cryptographically strong key.

The key is then used with the "Authenticated Mesh Peering Exchange" AMPE to establish a secure peering and derive a session key to protect mesh traffic, including routing traffic [35]. However as on date, the standard has been cancelled from the IEEE project.

This was achieved through network discovery and selection and QoS map distribution. The network discovery and selection may be provided in the following ways: 1. The discovery of suitable networks through the advertisement of access network type, roaming consortium and venue information. Nowadays, with mobile users whose devices can move between 3G and Wi-Fi networks at a low level using Actually, IEEE With the usage of external network authorization, the AP also provides service to the previously unknown STAs.

It introduces protected management frames with the help of mechanisms that enable data origin authenticity, data integrity and replay protection. To allow for this, the standard also adds three new concepts: 1. DLS allows two stations to communicate directly with each other without the requirement of an AP.

This standard basically provides direct-link setup enhancements to the IEEE The direct-link setup is made independent of the AP by tunnelling the protocol messages inside data frames. It specification adds a "fast session transfer" feature, enabling the wireless devices to seamlessly make transition between the legacy 2. To operate with optimal performance and range criteria, the IEEE Many users in a dense deployment can all maintain top-speed performance, without interfering with each other or having to share bandwidth as with the legacy frequency bands [].

The likely enhancements to A protocol to communicate management frame prioritization policy is specified in this standard. This standard is expected to be published by the end of It is expected to provide a multi-station WLAN throughput of at least 1 Gbps and a single link throughput of at least Mbps [45]. This is achieved by extending the air interface concepts which are embraced by It will use cognitive radio technology to identify white spaces it can use.

However, this cognitive technology will be based on an authorized geolocation database. This database will provide information on which frequency, at what time and under what conditions networks may operate. It will also enable devices based on the IEEE In addition it will provide improve coverage range which will allow new applications such as wide area based sensor networks, sensor backhaul systems and potential Wi-Fi off-loading functions to emerge [48]. This standard is currently under development and is predicted to be finalized by The amendment is also intended to maintain backward compatibility with This standard is scheduled to be finalized by the end of This creates opportunities to deliver new services, as the IEEE This information about services is to be made available prior to association by stations operating on IEEE This standard is scheduled to be published by Security One of the prime concerns in wireless networking is security.

As WLANs operate over the shared medium, eavesdropping by unauthorized people and critical information may be accessed with the use of malicious technologies.

Although WPA and WPA2 are much more secure and provides good protection still it is not secure enough to be contend with. More complex encryption algorithms need to be implemented without decreasing the MAC layer throughput.

There was significant improvement in the data rates provided by the IEEE However, the 40 MHz channel required to support such data rates are not available in many countries. The more recent IEEE But this data rate is even still quite low as compared to the 10 GHz capacity of the wireline network standard Increasing the PHY layer data rate alone cannot solve the throughput problem; but the MAC layer also needs to be changed.

Two amendments IEEE Unlike IEEE HiperLAN A HiperLAN network chooses its own channel by using a DFS mechanism, which changes the operating frequency of the network when the current frequency is occupied by another network. Table 2 summarizes the various modulation techniques of the PHY layer.

The range of operation of HiperLAN is 30m indoors to m outdoors.