[Interview] Mobile Communication Speed Reaching Limit, Qualcomm CEO Says

Sept 5, 2008 18:15 Hiroki Yomogita, Nikkei Electronics

LTE, WiMAX, HSPA Evolution, etc ... new technologies are now being introduced in the world of mobile communication. Depending on system configuration, it might be possible to realize a high-speed mobile data transmission of up to 100Mbps, more than 10 times faster than the current speed.

How does Qualcomm Inc, which deals with chipsets for mobile communication devices, think about those new technologies? We interviewed CEO Paul E Jacobs on the future of mobile communication.

- LTE, WiMAX and other technologies that employ OFDMA to enhance transmission speeds are currently drawing attention in the world of mobile communication. How does Qualcomm consider this situation?

Jacobs: First of all, the improvement of wireless links that enhance user throughputs is reaching its limit. If you compare the wireless link of HSPA+ (HSPA Evolution) with that of LTE, their difference in frequency utilization efficiency is only about 10%. It is small enough to be offset by noise.

There are more measures to improve the performance for each user other than the improvement of wireless links. For a higher speed performance, the mainstream method is to use a broader bandwidth and transmit more bits of data. But, there is another method: densely deploying base stations to shorten the distance between base stations and mobile terminals. Femtocell, which is often discussed in these days, is an example of this concept.

However, if femtocell base stations use a frequency equivalent to that of macrocell base stations, mutual interferences occur, probably reducing the network capacity. Therefore, we made notebook PC-sized base stations and placed them in hotels, homes and office buildings to research on how the two types of base stations interfere with each other and affect their networks. And we confirmed some interferences.

To reduce those interferences, femtocell and macrocell base stations have to exchange information to avoid interferences.

In the future, users will be able to set up store-bought femtocell base stations wherever they want, like access points for wireless LAN. To prepare for that future, we have to ensure that femtocell base stations properly interact with macrocell base stations. According to the results of our research, this effort will possibly result in eight times higher throughput per user.

In retrospect, an eight-times improvement is equivalent to that brought by the cell phone's shift from analog to digital. This is really an exciting fact. We are very interested in the fact that we can produce this much effect.

However, please remember that this cannot be achieved only by the improvement of wireless links. We need to improve the performance of the system. We believe that, among the next generation mobile communication technologies, management techniques for base stations will become very important.

Specifically, they include the techniques to reduce interferences, manage the transmission output of each user terminal and accurately control how to access to base stations and which base stations to be accessed.

- Do you mean it is more important to manage the entire system rather than wireless link technologies such as OFDMA?

(Continue to the next page)

24 Hours | 7 Days