Wireless VoIP

Wireless VoIP is Voice Over Internet Protocol (VoIP) running over a Wireless Local Area Network (WLAN), which are typically the 802.11 standard compliant. The callers can make and receive calls over WLAN using VoIP enabled handset, within the WLAN access point.

Skype bought a revolution in voice based solution through internet. Wireless VoIP got a good support from Skype, which introduced special handset to link callers to the Skype service via Wi-Fi connections. The users can log into the WLAN Access point with their user ID and passwords. Once they are logged in, they can access internet as well as place and receive calls. This avoids the need to have a computer or Laptop to log into the regular network which is connected to Internet.

While the users can leverage the Wireless VoIP using handsets, Internet Service providers (ISPs) will need to offer better services to their customers. ISPs can now offer Wireless VoIP services using the products/services of xG Technology or other similar companies.

These users may use a phone that supports Wireless VoIP to make calls. These phones communicate with the local access point/antenna. The call would then be relayed to the ISP handling the VoIP. The ISP facilitates the calls to other IP phones or the traditional phones.

Wireless VoIP is very useful in industries like health care and retail. The problem with Wireless VoIP is that, implementing and maintaining could be time consuming and expensive. Another problem is the risk of eavesdropping.

VoIP has already affected the revues of the fixed land line telephone network. Wireless VoIP could pose a threat to the mobile network operators. Wireless technologies like 3G, Bluetooth, WLAN and broadband wireless access can change the dynamics of voice revenues of mobile network operators. One advantage for mobile operators now is that the voice quality is better than that of VoIP and at cheaper cost.

However wireless voice applications in a limited area can leverage Wireless VoIP, as the mobile operators may find it difficult to provide a customized solution. WLAN may soon replace Bluetooth, which has limited range.

One problem with wireless VoIP is the coverage area. While WiFi, the most popular wireless solution, can support broad-coverage network, the WiFi access points can cater to a short range.

Wireless VoIP typically relies on active communications mechanisms. Due to the constant pinging, both the receiver and transmitter leave a dedicated communication channel open, leading to a very large load on the access points. Hence the system needs an automatic means of load balancing that hands signals off from an access point that is loaded more to a less busy access points.

A good wireless VoIP system shall handle collisions very quickly. VoIP signals are unpredictable in nature. When the access points get overloaded or too many signals are received at the access point, the delay in signals may compromise the voice quality.

Wireless VoIP device remains active both in a call and out of a call in order to properly handle the signal. Hence the battery life is reduced and the manufacturers of Wireless VoIP devices are working on technologies to preserve power during VoIP communication.

Voice over IP in future on WLAN on a single Chip

Many communication services using WLAN (Wireless Local Area Network) are being introduced. Wireless local data networks are now finding their way into residential, commercial, industrial and public areas. In earlier days, it was practically impossible to log into Internet from your Laptop in a hotel or Airport. Now all major air ports offer wireless hotspots and you can log into the Internet, if your laptop supports wireless access. Similarly Hotels, Shopping malls, coffee shops offer Wireless LAN.

It is very easy to add client access once the basic infrastructure of WLAN is in place. WLAN provides flexible network configuration and access with a low cost. WLAN is now on the increase in campuses and conferences. WLAN caters well incase of data communications such as e-mail, web browsing and internet. As new Voice over IP applications are being launched at regular intervals, voice over WLAN is becoming popular.

A typical VoWLAN (Voice over WLAN) system may be as below:

Voice over WLAN needs to address various discrete components like Microprocessor, LCD controller, peripherals, Keypad, WLAN MAC, Memories, RF etc. It also need to address user interface logic, audio interface etc.

All the above elements, if handled separately, it costs money. Hence the manufacturers and researchers are planning to integrate as many functions as possible into a single Chip.

Models and Suppliers

Motorola has launched its T31 Series VoIP handset for Windows Live Messenger service. This VoIP phone consists of a base station and a handset, where the base station connects the PC for enabling calls over Windows Live Messenger service and to a phone jack for placing standard PSTN calls.

This can display online contacts and phonebook. This facilitates caller ID with visual call waiting features. The advantage is its ability to contact users online quickly using the PC Connect button. Once can access low cost long distance Internet calling to standard landline phone numbers from T31 handset. Alarm clock, speakerphone in the handset, Mute and Hold facility, Voice mail are some other features.

Uniden and Philips are the other two vendors who offer a cordless solution for Windows Live Messenger. Microsoft claims that there are more than 240 Million registered users on Live Messenger.

Wireless VoIP - Future Changes

Many VoIP devices that provide excellent voice quality are available for you. They may offer some features very specific to the vendor and vendor’s VoIP equipment. You need to evaluate your requirement and the suitable product for you.

Demands and requirements of the users keep changing with time. Hence, pick up a phone/equipment that is scalable.

Changes in Wireless

Though most of the WLAN products follow 802.11b or WiFi, ever increasing demand of bandwidth by VoIP applications and/or wires video etc, new high bandwidth standards are needed to satisfy the future growth. Access Point proximity dictates the exact effective data transfer rate. Newer standards are expected to meet the demands of the bandwidth hungry applications.

ISM band seem to be crowded and poses a possibility of interference problems in case f Bluetooth, RFID tags, cordless phones, microwave ovens etc. 802.11a based wireless voice devices are not readily available on the market.

If one has 1Mbps bandwidth, it is good enough to have a good quality wireless voice quality. Some vendors who are mostly 802.11b compliant have announced support of 802.11a or 802.11g for a wireless VoIP application. However, in future when they do actually become compliant, they need to address the battery life.

Other standards to be addressed are Quality of Service or voice prioritization (QoS) by 802.11e and Security to address authentication and encryption by 802.11i. It is important to see how enhanced encryption can be utilized on existing hardware.

It is important to understand the impact of the new standards with regard to the required voice quality of the wireless voice application. One need to address the latency burden also. The existing mobile devices may need to be replaced, if the new encryption standards are to be implemented.

VoIP PROTOCOL

As VoIP technology is changing rapidly, the vendors have their own VoIP protocols, that suit them well. This is due to the fact the global/international standards are not mature for implementation across the world.

Session Initiation Protocol (SIP) is emerging stronger, but does not seem to meet the requirements of many corporate customers and is still in the process of evolving to a richer set of features. However, we need to see the standards sooner to avoid interconnectivity issues arising later, as user shall not get stuck down with vendor specific VoIP and wireless equipments.